Well, I'm spending money that I shouldn't be spending over here haha. I just bought a muncie m20 for my car which I'm paying for slowly right now (I'm good friends with the guy I bought it off of). I was browsing craigslist and found a 400sbc from 1976 for sale "make offer", its a shortblock and it will need to be done over completely, but I offered $150 and he said its yours. I've always wanted to build a 406 with my top end, so now I need some advice, this is going to be a "down the road" project but I want to map some stuff out now.

I want to reuse my top end: Trick Flow 23 Degree cylinder heads, 195cc intake runners, 2.02/1.6, 62cc combustion chambers. Performer RPM intake with a 650 Speed Demon. Hooker 1 5/8 Headers will stay too.

I was thinking just a stock rebuild, bore it over .030 to get it to 406, I want something around 10.25 comp even though its a street car, I know this is doable with the aluminum heads, and have no problem running 93 octane. What do you guys think, what cam would be ideal? I'm running a 268 in my current combo and it has a nice pull, I know this cam in the 400 would be a hell of a performer but I know I can go bigger.

BTW the rear is next on the list, some 3.55's and a posi, so the cam must be accomodating to that.

A voodoo 276 hydraulic flat tappet is a nice cam for this motor. With yoru compression, heads, an rpm intake and drivetrain, youve got solid 12 second potential with that cam in there. Im actually gonna build a similar setup after the car itself is far enough along. Recently, I found a guy running a 406 that is almost scary how close his combo is to my proposed one. Its a 406 with I beleive 9.8:1 comp, AFR heads, voodoo 276 cam, 3.73 gears, rpm intake, 2500 converter. I saw the similariteis in the motor, so I inquired about timeslips, and his chevelle has clicked off some high 11's. That made me happy to hear cause as I said, Im going to be getting into a very similar build with a similar drivetrain in a similar year and weight chevelle....same cam as well with either the RR 200's or AFR 195's. So with some work and everything coming together right...there are 406 inchers with that cam seeing 11's. When I thought it up, I was expecting 12.20's at best with that motor. So, to hear that others have built very similar deals and found their way into the 11's is pretty re-assuring, and Id think that it could generally be a low 12 car without tons of effort(and maybe Id get lucky enough to run some 11's too). Youve got solid 12 second potential as well, as long as things are under control with the 4 speed!

That awesome, that was actually the first cam that came to mind ironically, whats the deal with the heads and steam holes, do I have to drill?

Man, now i wish I had the money to do it now, but like I said i'm going to have to wait atleast a year before I touch the engine, muncie first :D

406, a Compcam 280H, Protopline 200's,5.7 rods,and mid 12's easy (could be better if I could hook).

I run a similar combo:

408 sbc
afr 195's
rpm air gap
750dp
comp solid xs274s
9.7 to 1
5.7 rods
1.75 headers
3" dual exhaust x pipe
3.55 posi

I have yet to run it but it feels like a beast.

Do you have to drill the heads for steam holes??

The term "steam holes" is not really correct. The holes keep steam from forming in that part of the block by providing a path for air that can get trapped in that part of the block. Some consider that a weakness in the 400 block. I think the only weakness in the 400 block is they didn't make enough of them. Check out Greg's other 400 post.

Detonation, not horsepower, is the real destroyer of engines. With aluminum heads, 10.25:1, and proper timing, which means no cross-firing, your 400 should run forever. If it were my rebuild, and the intended use was just a good running REAL street motor, I would keep stock rods and try to keep piston weight the same to avoid a balance job. Spend that money on decking, deck plugs, and honing. IF the main bores looked round and straight, and they probably won't, I'd try to get by without align hone, too.

so no drilling required, i figured a .030 over and a line hone would be ideal, new bearings throughout, reuse the crank and rods to save money, new pistons, voodoo 276 and my current top end.

Can't wait, but its going to be about a year before I can start into this, this summer is the tranny, than the rear.

so no drilling required, i figured a .030 over and a line hone would be ideal, new bearings throughout, reuse the crank and rods to save money, new pistons, voodoo 276 and my current top end.

Can't wait, but its going to be about a year before I can start into this, this summer is the tranny, than the rear.


You got to drill the holes to run on the street.

With those heads, brodix reccomends not drilling them. They reccomend a particular head gasket to use instead. Mike Lewis(AKA wolfplace) informed me of this before when I asked him the same thing long time ago. Ask Mike or brodix about it to make sure you end up with the correct gasket for your application.

save your block only bore it 20 if it will clear and it will be around a few more years.you can get 400 head gaskets with or without the steam holes.myself if the car was a street car and seing alot of red lights and ideling i would use the steam holes.most machine shops only charge about 10 to 15 dallars around hear to drill them.you can do it yourself but do a study on it because two of the holes are at a angle to miss the bolt holes.i only drag race so i have no need for the steam holes.maybe mike lewis will chime in on that if he says not to drill i would take him at his word.my brother 70 full body chevelle minus air with 406 195 arf heads flat top pistons victer jr intake 194s comp cam and 1 5/8th headers turbo 400 and 410 gears ran 12.40s in the 1/4 mile.the flat tops made to much compression for the street in my book for the gas you get nowadays.

I've been through a few 406 combo's in my vette,and am happy with my current setup. I've run the RPM intake with Comp's XE-274(which idled like a stock 350),also their XE-284.The XE-284 had a little more "attitude at idle and pulled nicely to 6500 or so.

I broke a pushrod,and decided to switch to a solid Isky(Z-35),and it idles like the Comp XE-284,but will pull clean to 7000 rpms.I did swap to the Vic Jr,with the solid cam,and drivability isn't much different than it was with the RPM intake.

I wanted to share this real world feedback,because it took me three combo's to get this.I feel a muscle car should shake at idle,and throw you back in the seat with a hard launch,so if that's what you're looking for,give it a shot.

The AFR 195's (74cc)and flattops give 10.1:1,and pump gas has been no problem.The only issue I had was the stock cooling system could not keep up. I swapped to a Griffen 31x19 aluminum radiator,and now it'll run at 180 degrees all day.Estimated hp is 480-510,and it should put the 3200 lb vette in the 11's easy.

"save your block only bore it 20 if it will clear and it will be around a few more years."

Can .020 over pistons be obtained without special order? That would have been my advice if I knew they were available. I'm interested in finding out about the head gaskets that don't require "steam holes."

I'm following in Eric68's footsteps (thanks!) and bought .020 flat top SRP pistons from Mike Lewis. Along with a Scat 3.800 crank and Scat 7/16" capscrew 6" rods = 410.

"Fel-Pro 1014, with predrilled steam holes for 400, must modify heads per instructions"

So I guess that means they will need to be drilled, the problem is that until the 400 swap the heads will be on my car since its my driver. Hopefully I can work something out with a machine shop to get them done on a specific date.

That solid cam setup sounds awesome, but doesn't that mean I'll be adjusting the valves all the time? Also I want to reuse the stock crank and rods, isn't 7000rpm pushing it for stock components?

EDIT: wow looked up that cam, i really like the idea of revving to 7000 but man, 360 bucks?? yeah right, I think I'll stick with that voodoo 276 which from the way the voodoo line was designed is similar to a comp 284

Rick Dorian: Sounds like that 3.800 crank and +.020 piston should be some kind of permanant post for everyone wanting a 400 SB. Wish I had known about that when I built mine. Where was this forum when I needed it? Mike should be selling a bunch of that combo. I need to 'get out' more.

Wait can someone please explain the 3.8 crank and +.020 piston thing to me, I must have missed the topic about it, why is this a good idea?

Eric68 built this combo which I think is great. With a 4.145 bore, 3.800 stroke you get 410.

With those heads, brodix reccomends not drilling them. They reccomend a particular head gasket to use instead. Mike Lewis(AKA wolfplace) informed me of this before when I asked him the same thing long time ago. Ask Mike or brodix about it to make sure you end up with the correct gasket for your application.


Did Trick Flow modify their cooling passages also to work without steam holes? I haven't used any of the two heads (Brodix/Trick Flow) on a 400 build. Most recommendations is if any low speed or idling, such as street use, is to be done, the steam holes are needed to keep the water moving. I have never taken the chance of not drilling them because even if the temp gauge never showed a "hot" condition, you still would not know if the water was trapped and boiling.

Eric68 built this combo which I think is great. With a 4.145 bore, 3.800 stroke you get 410.On any of the 400 blocks I would try and run the longest rod possible.JE makes a lot of pistons for the 6.125 rod.

280CompCam,406ci
http://s10.photobucket.com/albums/a130/Dougs68Camaro/th_DSCF0001.jpg (http://s10.photobucket.com/albums/a130/Dougs68Camaro/?action=view&current=DSCF0001.flv)click the pic

Now I cant wait, like I said this is going to be a budget build so custom pistons and oddball rod lengths are out of the question for me.

How hard is it to drill these holes, is there a margin for error with the 30 degree holes? How deep do you go?

That 280H sounds wicked but I really want to try out a voodoo cam, my current combo was built before they came out. The 276 should be quite similar, that idle is what I would like though, i'll have to see if Harold chimes in..

I didn't pay that much for my solid cam,I think maybe $180. or so. It is a flat tappet solid,not a roller.I have just relashed it for the first time,not that it needed it,but I was bored and it gave me something to do for an hour or so.

After relooking at your combo,perhaps the 7000 rpms would be a bit much,especially with a 2.70 gear. I meant my post to illustrate a 406 can run a much bigger cam than a similar 350,and still be very tame.My Isky is 254@.050,and does shake the car at idle,but the XE-274,which was 230@.050 idled smooth,but only pulled to 5500,maybe 6000 tops.

If you want the idle to be a bit nasty,go with the Comp XE-284 which has 240@.050,and adjuct the idle speed to around 650-700 rpms. I did,and it would shake the car,but not stall at the lights.

20 over pistons are not special order at most places to my knowledge.and felpro and detriot racing gaskets come with steam holes or not .as for as adjusting solid lifter all the time no if your using poly locks.solid cam is the only way to go for performance for me .

I'm following in Eric68's footsteps (thanks!) and bought .020 flat top SRP pistons from Mike Lewis. Along with a Scat 3.800 crank and Scat 7/16" capscrew 6" rods = 410.
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And balanced very nicely too if I do say so myself,, :p

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Now I cant wait, like I said this is going to be a budget build so custom pistons and oddball rod lengths are out of the question for me.

How hard is it to drill these holes, is there a margin for error with the 30 degree holes? How deep do you go?

That 280H sounds wicked but I really want to try out a voodoo cam, my current combo was built before they came out. The 276 should be quite similar, that idle is what I would like though, i'll have to see if Harold chimes in..
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Stick with your choice in cams for a hyd, I am pretty sure Harold rates his at .004 not .006 lifter rise but I ain't a Lunati dealer so I am not sure on this.

As for rod length,, you are not going to find any magic power here internet experts aside.
I like a 6" rod with the 3,75-4" stroke deals as it affords internal balancing which I feel pretty strongly about but as for power & rod length,,, if the R/S ratio is within reason,, this is just people repeating what they have heard in most cases.
This is not just my opinion but the opinion of a lot of folks I consider much smarter than myself.
You will get crap about cylinder wall loading, piston dwell, & in theory it is correct info but have someone actually show you the difference.
Most of it is just way overblown,,,
If the R/S ratio is within reason you are not going to find any magic gains
In my opinion this is about 1.5-1.9 for almost anything we are discussing here & has been proven in testing a number of times.

Steam holes,,
With stock type heads & blocks they should be there if you are going to drive it on the street much.

With aftermarket blocks or Bowtie blocks they are not necessary as you do not have the same problem with a steam pocket but with these as well as stock blocks for circle track I modify the cooling system with returns from the rear of the head.

The only holes that I feel are really necessary are the two center ones. This is where the heat issue is.

With most aftermarket aluminum heads you had better contact the people that made the head before you start listening to people who have not drilled them before as it is not the same as a stock head.
AFR's to be drilled need a hole drilled about 2"'s deep at a 30deg or so angle before you will reach water.
Brodix does not recommend them with their heads & a modification to the gaskets that I believe is shown on their site. If not it is in the catalog or they will send it to you.

I have never used a set of Trick Flows so I cannot comment on drilling them. Ask Trick Flow but I would highly suggest you not start drilling on them until you talk to them,, :)

As for the Isky it is no where near $320,, at least not from me,,

How hard is it to drill these holes, is there a margin for error with the 30 degree holes? How deep do you go?

.
I drilled my sportsman 2's at home and they're cast iron.I used the steam holes from the old 400 heads as a guide by inserting a drill bit into the holes and copying the angle and depth.It was a little hair raising but was pretty easy and it saved me $50.I used a drill press but people on here have said they just used a regular drill.Make sure to use a NEW drill bit of the correct diameter.
Also it goes without saying find out what the cyl head manufactuer recommends.

Wolfplace, how often would that solid have to be adjusted on the street if I were to go that route?

Yeah i know Harolds cams are rated different and basically are rated one lower than their comp counterparts (262 voodoo = 268 comp, 268 voodoo = 274 comp and so on).

I emailed trick flow but haven't heard back from them yet, they say they must be drilled and it seems to be a standard procedure, the straight down holes are pretty easy, the ones that have me worried are the 30 degree holes.

Like I said I'm wanting to keep the stock crank and rods, I'm trying to not spend money I don't need to. I'll probably get new pistons, something around a 14cc dish to get me a bit over 10:1 compression, new bearings and rings.

Is this motor internally or externally balanced? Would I need a new balancer or would I be able to reuse my 350's balancer?



I was discussing this with a friend, I'm sure I'm going to get hugely mixed reviews, but If I were to build this myself would this be possible:

1. Get the block cleaned up, bored .030 over
2. Reuse stock rods and crank, new .030 over dished pistons with rings, (would the rotating assembly need to be balanced? The only thing changing is hte pistons and they are all within spec of each other...
3. Measure for new rod bearings. Would the cam bearings need replacing? I've never heard about having a problem with cam bearings, but I'm guessing the block getting cleaned up would require pulling them out anyway?

When I went to the only local machine shop they estimated $2300 for a 383 conversion of my stock 350 motor, this was just the shortblock, new rotating assembly bearings etc. full assembled. I would like to build this 406 for under $1000, which is very doable assuming they don't try to screw me over on anything. I don't want to do anything sketchy to save money and pay for it later. What would it cost to have a machine shop assemble that shortblock if the only truely new/expensive part is the actual pistons? (obviously there will be labor and costs for bearings rings boring assembly)

Wolfplace, how often would that solid have to be adjusted on the street if I were to go that route?

Yeah i know Harolds cams are rated different and basically are rated one lower than their comp counterparts (262 voodoo = 268 comp, 268 voodoo = 274 comp and so on).

I emailed trick flow but haven't heard back from them yet, they say they must be drilled and it seems to be a standard procedure, the straight down holes are pretty easy, the ones that have me worried are the 30 degree holes.

Like I said I'm wanting to keep the stock crank and rods, I'm trying to not spend money I don't need to. I'll probably get new pistons, something around a 14cc dish to get me a bit over 10:1 compression, new bearings and rings.

Is this motor internally or externally balanced? Would I need a new balancer or would I be able to reuse my 350's balancer?



I was discussing this with a friend, I'm sure I'm going to get hugely mixed reviews, but If I were to build this myself would this be possible:

1. Get the block cleaned up, bored .030 over
2. Reuse stock rods and crank, new .030 over dished pistons with rings, (would the rotating assembly need to be balanced? The only thing changing is hte pistons and they are all within spec of each other...
3. Measure for new rod bearings. Would the cam bearings need replacing? I've never heard about having a problem with cam bearings, but I'm guessing the block getting cleaned up would require pulling them out anyway?

When I went to the only local machine shop they estimated $2300 for a 383 conversion of my stock 350 motor, this was just the shortblock, new rotating assembly bearings etc. full assembled. I would like to build this 406 for under $1000, which is very doable assuming they don't try to screw me over on anything. I don't want to do anything sketchy to save money and pay for it later. What would it cost to have a machine shop assemble that shortblock if the only truely new/expensive part is the actual pistons? (obviously there will be labor and costs for bearings rings boring assembly)
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On the angled holes, it is pretty easy once you are sure of the angle & position.
Easiest way is to start them at 90 degrees to the surface for about an eighth inch & then tilt the bit the proper angle. This will keep you from "skipping" across the surface of the head which will ruin your day.

If you use stock rods which I don't recommend you will be externally balanced for sure & need a 400 damper & flywheel.
5.7's will internal balance with a light enough piston & rod small end. but all 6" stuff will internal balance.
The 5.565 rod is getting a little short for my taste as far as R/S ratio goes but there are a number of them out there running along quite happily.

As for machine shop pricing, it just depends on what you want & what the shop is comfortable doing but to answer part of your questions, yes, at a minimum you will need new cam bearings installed, you cannot clean the block with the bearings in it especially on a small block Chevy,
Get the pistons installed on the rods.
block bored & honed.
I personally do not build anything that is not balanced. I do not hone a block without torque plates & I do very few blocks that are not square decked with the exception of numbers matching stuff & I do not assemble short blocks without checking all the clearances so I am not the cheapest shop out there :D

Alright so basically I can reuse the crank and block but everything else must go, I guess it would be wise to just have the shop do the build.

Since I'm going to have to change the rods what is recommended, remember i don't necessarily want the "best" i want to spend as little as possible while still building a reliable motor.

[QUOTE=Wolfplace]=
And balanced very nicely too if I do say so myself,, :p

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That's an understatement :)

It's more like gearhead jewelry.

Alright so basically I can reuse the crank and block but everything else must go, I guess it would be wise to just have the shop do the build.

Since I'm going to have to change the rods what is recommended, remember i don't necessarily want the "best" i want to spend as little as possible while still building a reliable motor.


My best advice to you is: Get in touch with Wolfplace and let him get you a complete rotation assembly with 5.7 rods, pistons, and crank. The cast crank and hyper pistons setup will take some hefty hp numbers. As for the build, you can do it if you have any mechanical skills at all. One point to remember is it can never be clean enough. Just when you think it's clean, clean it again.

My best advice to you is: Get in touch with Wolfplace and let him get you a complete rotation assembly with 5.7 rods, pistons, and crank. The cast crank and hyper pistons setup will take some hefty hp numbers. As for the build, you can do it if you have any mechanical skills at all. One point to remember is it can never be clean enough. Just when you think it's clean, clean it again.

rotating assembly would be nice, something prebalanced and partially assembled but I can't afford that. the new crank alone is a huge cost compared to everything else.

believe me if it were that cheap and easy it would be built tommorrow haha, but I'm doing a muncie swap first, this is next summers project unless my motor decides to die this summer haha

rotating assembly would be nice, something prebalanced and partially assembled but I can't afford that. the new crank alone is a huge cost compared to everything else.

believe me if it were that cheap and easy it would be built tommorrow haha, but I'm doing a muncie swap first, this is next summers project unless my motor decides to die this summer haha


Have you priced any of the parts? The reason I ask is because a new crank is under $200.00 The whole kit is around $1000.00 with balancer and flexplate included along with bearings. You get crank, rods, and pistons. You may be able to get away with your old crank, but that is like putting a grenade in there. You never know when it will go. Just check it out and think about it. The worst feeling in the world is when your engine flies apart.

Would it be possible to buy a whole kit as you mention from wolfplace at that price? I've never seen a rotating assembly that cheap for a 400 :/

I'd be willing to pay a little extra to have the rings installed and the pistons installed onto the rods if possible. Like you said its not too bad to put it together once everything is within spec..

I'd sure give it a try. You can always sell your 400 crank locally to someone building a cheap 383 or even a 400. To have one done right is worth more than something that's been cobbled together. I don't recall anyone every saying anything other than positive things about Mike, I know I'd sure give him a shot.

Here's a kit at www.jegs.com I would check with Wolf place first though and see if he can hook you up with something even better.


Quality Components At A Value Price!
Chevy Street and Strip
Includes 5140 Steel SIR lightweight connecting rods, std/std cast steel crank, Keith Black hypereutectic pistons, Clevite rod and main bearings, plasma moly cast iron ring sets



356-13014 SB-Chevy 400ci Street & Strip Rotating Assembly
Bore x Store: 4.155'' x 3.750''
Rod Length: 5.700''
Pistons: Keith Black -5cc Flat Top
Comp Ratio: 12.5:1 w/58cc, 11.6:1 w/64cc, 10.2:1 w/76cc
2-piece Rear Main Seal



$1,187.99

Would it be possible to buy a whole kit as you mention from wolfplace at that price? I've never seen a rotating assembly that cheap for a 400 :/

I'd be willing to pay a little extra to have the rings installed and the pistons installed onto the rods if possible. Like you said its not too bad to put it together once everything is within spec..
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Thanks guys but to answer the question simply,,, no I cannot sell a complete balanced rotating assembly for that price, not with anything I am comfortable selling & anything else is just the parts which you are going to need balanced locally so be sure you are comparing apples to apples ;)

I guess I'll just go to my local machine shop at that point, but I'll probalby get the pistons/rods/crank myself and have them just get hte rings/bearings etc. and put it together.

Pistons:

http://store.summitracing.com/partdetail.asp?part=TRW%2DL2352F30&N=4294891096+4294908395+4294908216+4294840135+4294 925062+4294872582+4294791059+4294891030+115&autoview=sku

Should give just a tad over 10:1

Crank:

http://store.summitracing.com/partdetail.asp?part=ESP%2D104003750&N=4294838995+4294871923+4294908395+4294908216+4294 840135+4294925062+4294785225+4294872604+115&autoview=sku

And a set of 5.7 rods which will run another $250 according to summit. Voodoo 276 cam, give all that to the machine shop and have them order the rings/bearings and clean/bore/balance/assemble the whole thing.

Get a new 400 balancer from summit (about 60 bucks). I'm converting to a manual tranny do I need a new flywheel for the 400 vs. the 350?

Am I missing anything?