[BH]

Back in February I pulled a 77 Camaro out of a barn that had been sitting there for the better part of 20 years. We got the old 402 running but it was either already injured or I toasted it within the first few test drives. Took it out to the strip and it could barely pull 16 seconds. Pulled it apart and found a couple of missing cam lobes and a spun rod bearing. It's over at the machine shop right now getting all the usual stuff done to it, including:

• cleaned & magnafluxed
• check align hone
• probably bore .030 over
• torque plate hone
• crank grind

I'm probably missing some stuff that they're doing, but basically whatever it needs.

Block

I'd like to build this into a street/strip motor for my 67 300. It's a stock bore two bolt main 402 block. It will see more street action than strip action, as I am turning the Camaro into my bracket car, and putting a manual transmission back in the Chevelle. I definitely want to be able to run pump gas.

Crank

The guys at the machine shop said it looks like the stock steel crank should be able to be turned.

Rods

The guys at the machine shop said that a new set of rods is the way to go, as pulling apart and reconditioning the good ones is very labor intensive, and I need at least two new ones anyway. Like I said, mostly street but definitely some strip application. It would be cool to be able to put a little spray on it in case I get in trouble on the starting line, but I don't plan on boosting the motor at all. Any thoughts on rod selection?

Heads

For the initial big block build I plan on going with the stock 1972 6272292 oval port open chamber heads. On my small block I'm running right around 11:1 ratio with pump gas, no problem, but I have relatively modern heads on it. I've read that the 2292 heads are more prone to detonation than heads without the quench area cutaway around the exhaust valves. I am going to clean them up, do some light port work and replace the valves. What is a reasonable compression ratio for these heads so that I won't have to worry about detonation when running 92+ octane gasoline? What about head gasket selection? I seem to remember going with ultra-thin head gaskets on my small block build for some reason.

Pistons

The pistons that came out of it are slightly domed. I run hypereutectics in my small block. Last I checked, springing for forged is quite a bit pricier. I'm not against going with forged if that's what my application calls for, but I'm not into wasting money for no reason either. I'm thinking that if I want to spray at all I should probably go for forged. Any thoughts on piston selection?

Rings

I've used moly rings in my small block builds. Would that be appropriate for this build? Any specific recommendations?

Valvetrain

I'm pretty clueless here. My guess is that a roller hydraulic cam would be the ideal way to go. I've toasted enough hydraulic flat-tappet cams in my day, and mechanical seems overkill for this application, but please share your thoughts! This sucker had a (suspected Erson) cam with the number 950616 stamped on the end. I measured the lobes and it seems like it's around .570/.590 lift, but I don't have the tools to measure the duration. I have no experience with roller cams or big block cam serection at all. What do I need to take into consideration? How should I approach selecting a cam? I obviously need some low-end vacuum, but I want it to sound mean too.

Ignition

Off the shelf street fire HEI.

Fuel Delivery

This sucker came with a Weind tunnel ram with dual Carter carbs on it. I also have a dual-plane single 4 bbl manifold that I can strap any number of different carbs to, but I'm thinking that I'll probably end up putting some Hilborn electronic fuel injection on this thing eventually. I'm not nearly as concerned with top-end stuff as I am with bottom-end stuff at the moment.

Headers

I want to get some nice looking headers that will stay decent looking. I'm open to stainless, thermal coated, ceramic coated, whatever really. I'm looking at Jeg's wondering what the differences between all the different options are. Also, what size primary tubes and collectors should I be shopping for?

The Car

This is going in a 1967 300 that weighs in somewhere around 3300 lbs with driver. It's got 4.11 gears and 28 inch tall tires. I intend on driving this thing to Kroger more often than taking it to the drag strip, but I definitely want to run some UMTR races with it. I'm probably going to end up getting a Tremec for it, though I do have a couple of Muncies laying around that I could use in the time being.

Other

What have I missed?

 

[MikeN]

I like it. A small hydraulic roller cam will be mint.

 

[Malibu ss 64]

Rods:
Scat pro stock or scat pro comp.
Pistons:
Hyper will be fine but I like forged.
Cam: Hyd roller 220-230 duration, maybe isky 218/228.

 

[shovelrick]

Before spending a bunch of $$$ on the old stuff and still in need of pistons why not a Scat rotating assembly? pricewise I think you'll be better off

 

[oldguy67]

i'm guessing if you use what you already own, keep comp. around 9.5:1 use that isky roller and dual-plane intake with a 750 of choice, you will have a nice STREET engine. When going to the track only means a couple of times a year, lean more towards street manners.

 

[Aml383]

Why use 72 292 heads ?
Already got em ?

 

[BH]

Why use 72 292 heads ?
Already got em ?

Yeah, they're the heads that came on the car. From what I've read they're decent. I could get different heads but I'd rather spend that money on the race car motor.

Rods:
Scat pro stock or scat pro comp.
Pistons:
Hyper will be fine but I like forged.
Cam: Hyd roller 220-230 duration, maybe isky 218/228.

That cam looks nice but I think the 228/238 is a little closer to the setup I'm looking for. Thanks for the recommendations. Summit says they're 4 moths out. Good thing this build isn't urgent.

i'm guessing if you use what you already own, keep comp. around 9.5:1 use that isky roller and dual-plane intake with a 750 of choice, you will have a nice STREET engine. When going to the track only means a couple of times a year, lean more towards street manners.

Yeah I think this is the general direction that I'm headed. I think I might have a vacuum secondary 750 laying around here somewhere.

Before spending a bunch of $$$ on the old stuff and still in need of pistons why not a Scat rotating assembly? pricewise I think you'll be better off

I'm having the crank turned. It costs like $90.

 

[shovelrick]

Autotec/Racetec are a very nice forged piston and reasonably priced compared to other name brands, they're on my Manley rods and Scat crank

 

[BH]

Update on the numbers:

It will be 0.030 over on the stock 402 bore, so 4.155" bore
0.010 under on the mains
0.020 under on the rods

Current thoughts on parts:

Considering KB160 pistons
Considering Isky 396275-284 complete kit
Considering Scat pro stock rods w/bushings

Still no thoughts on:

• rings
• head gaskets
• headers

I haven't thought about valves much yet either.

 

[shovelrick]

Total Seal rings
Patriot 1 7/8 coated headers
Felpro for head gasket brand

 

[Malibu ss 64]

Update on the numbers:

It will be 0.030 over on the stock 402 bore, so 4.155" bore
0.010 under on the mains
0.020 under on the rods

Current thoughts on parts:

Considering KB160 pistons
Considering Isky 396275-284 complete kit
Considering Scat pro stock rods w/bushings

Still no thoughts on:

• rings
• head gaskets
• headers

I haven't thought about valves much yet either.

Rings: Moly rings Any name brand, mahle, perfect circle, Hastings, total seal etc.

Head gasket: Fel pro 8180PT2

Headers: Hedman 69198 or Dougs 313

 

[1975TypeS-3]

While doing the machining, have the deck drilled for parallel cooling - I do that on all of my big blocks that did not come that way - typically 1979 and earlier.

 

[BH]

Thanks for the tip on the deck drilling. I will double check with the shop to make sure they do that.

I've been working the numbers on pistons and it looks like -17cc dome is not going to get me where I want to be. I'm going to CC the heads and figure out the actual combustion chamber volumes I'm working with, because I see numbers anywhere from 105 to 119 reported anecdotally around the Internet. I'm thinking I'd like to be right around 10:1, but again, I've only ever built and raced small blocks. Is 10:1 reasonable for pump gas in a big block?

I've been going back and forth on Isky 396275-284 vs Isky 396265-275.

From the Isky manual, the 265-275 seems a bit weak for what I'm doing:

Good mid-range power. Good vacuum & good idle.
3.23-3.70 axle ratio. 9.5-10.5:1 compr. Computer compatible
with stage 1 chip. Stock converter. Up to 650 CFM Carb

The 275-284 seems more aligned with my vehicle:

Excellent mid-range perf. Fair idle. 2000 stall.
3.70-4.10 axle ratio. Up to 10.5:1 compr.
Up to 750 CFM Carb

This describes my previous setup pretty closely. I've got a TH350 with a 2800 stall converter and 4:11 gears and a 750 double pumper at 11:1, but again, small block with modern heads.

Is anybody out there running 292 heads around 10:1 on pump gas? Is that reasonable? I want to get the compression ratio figured out before I make the cam selection.

 

[70ss396_kid]

If it's still at the machine shop, consider zero decking the block. Finding off the shelf head gaskets for the baby big blocks is getting harder and zero decking will let you run a more conventional thickness head gasket while not giving up compression/quench. Just went through this with my 4.155 block, and had to custom order head gaskets to get the bore/thickness I wanted. I should have had it zero decked.

Edited to add: if your decks don't need surfaced, consider running a shim gasket to get your quench in line and add a little compression.

 

[BH]

CHANGE OF PLANS

I blew up my small block during the bonus race at the bracket finals last weekend. The big block is now going to be built into a race gas guzzling super street motor. More details to come.

 

[BH]

Well, I finally bit the bullet and ordered heads. Went with the AFR 3640 set up for a mechanical roller. Right now I'm trying to figure out pistons. These heads have a heart style combustion chamber. I'm looking for forged pistons for a 4.155" bore and 3.76" stroke. The heads have 112cc chambers stock. They can be flat-milled down to 104cc.

The only thing I've found so far that comes close to what I'm looking for are these Speed Pro pistons which would put me at about 10.7:1 without any machine work to the heads. My only hesitation is that I have no idea if they'll actually fit. I don't mind trimming them down a bit if necessary, but I don't want to buy something that's totally incompatible with my setup.

Should I just be going with custom pistons at this point? I wouldn't mind pushing the compression ration a notch higher. Everything I've seen with domes bigger than the Speed Pros specifically call for open chamber heads.

 

[Aaron]

You cant really go wrong with any selections on roller cams, if you go that way for what your doing. If you stay with a flat tappet, there are issues you should know about. Jones Cams, Bullet, Howard, and Isky are better brands.

Dont see alot of 396 or 402 builds much anymore. Great for what your planning to do with the 67.

You might visit the transmission forum. If you have to rebuild a Munice these guys can help. Jody over there has alot of information on Munice setups getting a overdrive and etc. Paul Cangialosi also is a guy who does alot of work with Munice's in changing the gear spread to better use those deep gears.

Article below should help you understand more if you do a lot of the work yourself or help you communicate with your builder better.

Dynamic CR (uia.net)

 

[Lew540]

10.7 Compression ratio with aluminum heads is fine you might need a little more cam but should be fine. I run 10.8 to 1 in my 540 on pump gas - aluminum heads. The Muncie is nice but a Tremec with more gears is better. The 4.11 good gear for 402 especially if you have an overdrive. You can check out some magazine articles on line and they have some good 402 builds with a modern day flair - ie roller cam and newer heads.

 

[Rosinbluth]

Well, I finally bit the bullet and ordered heads. Went with the AFR 3640 set up for a mechanical roller. Right now I'm trying to figure out pistons. These heads have a heart style combustion chamber. I'm looking for forged pistons for a 4.155" bore and 3.76" stroke. The heads have 112cc chambers stock. They can be flat-milled down to 104cc.

If your not already aware and planning, I'd take the heads in to a reputable machine shop and have them do a touch up on the valve job and check the stem to guide clearance. Seems like any brand can always use a light touch up and check before final assembly.[/QUOTE]

 

[BH]

Oh I should clarify, the 402 is now going into the Camaro we drug out of that barn last February, not the Chevelle. I need to figure out what I'm doing motor wise with the Chevelle, but that's not really a big concern right now, as the interior is being redone on a rather relaxed schedule.

So the 402 is going in front of a glide in the Camaro.

@Lew540 I appreciate the info on the heads. I'll probably put a Tremec in the Chevelle, but that's on the back burner.

@Aaron Appreciate the dynamic CR link and the contacts for Muncies. I have a couple of those I need to finish rebuilding.