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400 Small Block Build And Dyno Test

56K views 341 replies 53 participants last post by  cage2592 
#1 ·
A forum member had me build a mild 406 for his 71 Chevelle, I thought I would post some pictures. I had a very nice thick 817 production block, bore and stroke 4.155 X 3.750, with a 7/16 6 inch rod and a Mahle piston, we ended up with 10.3 compression. The cam is hyd roller, 234/238 @ .050 .560/.530 lift on a 110. We used a AFR 195 head with modifications and a performer RPM air gap intake with a 1 inch open spacer. Carb is a AED 750 CFM. We plan on testing different distributers, locked and with a timing curve. Gas will be 91 octane from 7-11. Should be a interesting build. I should mention the valve job from AFR was a disaster.
 

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#41 ·
I never did ask about that, just assume the date wasn't working

See, LOL
 
#42 ·
Mike you made a wise decision having Mark do the build,perfectionist.
 
#44 ·
Very impressive, Mark....yet again. (Made me forget about the virus and tax season for a few minutes. I'm grateful!!)

In otherwise equal cars, do you think this SBC can run with one of your Peanut Port 467 builds?
 
#45 ·
Hi
Vortec Pro
Nice results

Any results for 6000---6500 ??. I assume tq has dropped quickly on/after about 6400rpm ??? Ie Max engine redline .

Strong results for 2500-3000,impressed . Surprised at how well this does at both ends of the tq/hp curves .
Where did the cam shaft come from brand etc ??

Be interesting to see what would happen if vic jnr or weiand 7530 team G . were fitted . Probably loose 25 ft/lbs below 4500rpm and again 15 hp above . Probably gain 200-300 rpm peak hp . Thoughts ??

Good job
 
#48 ·
hi
vortec pro
nice results

any results for 6000---6500 ??. I assume tq has dropped quickly on/after about 6400rpm ??? Ie max engine redline .

Strong results for 2500-3000,impressed . Surprised at how well this does at both ends of the tq/hp curves .
Where did the cam shaft come from brand etc ??

Be interesting to see what would happen if vic jnr or weiand 7530 team g . Were fitted . Probably loose 25 ft/lbs below 4500rpm and again 15 hp above . Probably gain 200-300 rpm peak hp . Thoughts ??

Good job
448 hp @ 6400
450 tq @ 6400
 
#50 ·
Did the deck have any cracks between the steam holes and the head bolt holes?

Did you treat the steam holes in the block in any special way?

Did you add steam holes in the heads?

For me:
I don't worry about the cracks between the steam holes and bolt holes. Seems every block I've torn down has them.

I've never treated in any special way.

Depends on the head and cylinder head manufacturer. With my E-Tec heads, did not add. With factory cast iron heads, I've added the steam holes to match the 400 block.
 
#52 ·
Mark, What distributor did you end up using and did you get a chance to try others like you planned? Also, what causes the small torque dip between 3100 and 3700?
 
#53 ·
I used my locked MSD ready to run dist first, then changed to the customers MSD street fire with mech advance, very little difference between the two. Not sure about the dip, probably from testing at such a low RPM, when tested from 4000-6100 no dip.

More pictures
 

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#55 ·
It run about 2 gallons of 91 octane through it, so no it did not get tested with a single plane. I have to ask: why would my customer with his 3700 pound car his wife drives with a 2800 RPM stall converter want a single plane intake?

The cam was made to my specification by Spirro Jennings @ Redline on his Landis CNC cam grinder, a master grinder I might add, on a steel core with a cast gear. 234/238/110.
 
#58 ·
Mark do you find that a stout SB like this performs better all-around than an equiv. BBC? In terms of driveability, performance at the track, mpg - these kind of things. Thank you.
 
#59 ·
It was very efficient other than that I can't say. A good street 467 will get all over it (406) when it comes to power though, I will say that, and much less money spent. But then theres the weight............

Take your pick
 

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#60 ·
Hi
Vortec pro
Thought the engine might have been tried with small single plain for comparison , considering a spacer was fitted to get more topend performance . A carby spacer does not fit that many under bonnet applications . Was not aware of specifics of vehicle setup either .
 
#62 ·
Swampy,


My old 406 fit under the hood with a 1" open spacer this AED 750, flat bottom air filter base and 3" tall K&N.


I'm thinking of trying a "Blow-through" Style carb hat with 4" silicone smooth tube that goes to an air scoop under the bumper and mounted in the air dam.


One thing at a time though.


Mike
 
#61 ·
I thought hard about asking Mark for this SB. My dilemma was a 550HP SB (I asked for 500+) or his 650HP 496ci. What swayed me first toward the SB was Marks quick availability of a 400. He's rightly so, picky about his cores and good 400s are getting harder to find. Had Mark said there was going to be an issue finding one and or driving up the cost significantly of a DART block, I would have went 496. Second was the fact that the car was already set up for a SB. Front springs were already matched to the weight and handling and the car is as low as it can be without avoiding certain roads for hazards. Third was all my parts I'm reusing, A/C, PS Brackets, water pump, etc... was all small block. Yes it cost me more but by the time you figure in collecting BB parts and suspension I would have been at the same price or more. Even going with a lower HP BB. Which if I was upgrading, why go low? Lastly, this SB HP/TQ/Weight ratios is outstanding and Mark delivered !

It’s my opinion that Mark made the best SB street combination that you’ll find for a fully dressed street car with accessories. It’s the details Mark contributes that make this motor and all parts compliment to get those numbers.

Mike
 
#67 ·
Ummm....no. Science and math say otherwise.

Now...is there a big difference between real flow numbers and BS flow numbers? Absolutely.

An engine is an air pump. Air Flow Matters.
 
#64 · (Edited)
But...but...but...it's fitted with peanut port heads!

I think if you take my 467 and put Mahle pistons in there with the same cam specs and a 781 head you can be looking at 650 HP/600TQ with some detail work. So lets look at the numbers, we will use my NHRA stock Buick for a comparison.

Buick run @ 3500 pounds 8000 DA 4800 feet elevation 11.45 @ 114 MPH 24.70 baro
370 observed dyno HP @ 6400 feet elevation 23.70 baro
512 corrected HP/558 TQ

406 small block dyno
394-401 observed dyno HP @ 6400 feet elevation, 23.31 baro
555 corrected HP/540 TQ

So the 406 in the Buick considering it would weigh 3350 and makes 20 observed HP more, carries the power much better, means at least 11.20s in my Buick, but thats at 8000 DA, so your probably looking at 10.60 in low altitude, but thats with a 800 RPM idle

Might have to try that test....hmmmm Buick 406 dyno / drag test?
 

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#66 ·
My logic or question was not faulty at all. I was simply pointing out that the same professional builder made a stronger 406 SBC than a 467 BBC. Same builder, same shop, same dyno, same altitude, etc. If you can find a 400 SBC block in good shape, they can make excellent power numbers.

To be fair, I would ASSUME that this build costs more than a peanut port 467 from Mark.

However, if you're already running a SBC, you can put a motor like this between your fenders and not have to modify anything else...so long as your tranny and rear-end can handle 550+HP.

In my car at my altitude, I'm guessing this motor would run 11.2x or so in the cold and around 11.50 in the heat....give or take a tenth. My chasis dyno put me at 361/360 at the rear wheels.....so I'm guessing that I'd make 470-480 on an engine dyno. This killer 406 has me covered by at least 70 HP.....possibly more.

It's simply an amazing SBC....from a builder who never disappoints.
 
#68 ·
Reelysalty I believe has forgot his meds as he doesnt make sense (which is most of the time). Cant set up a Holley but is an expert on SBC/BBC performance.
 
#69 ·
You can start by watching the link post #63
Well...you saw it on the Internet....so it must be true.

You go to that guy...I'll go to Mark. It's a Free Country.

BTW: There's more work, machining, and money in that motor than you likely realize. And the parts mentioned do not simply just bolt together to get those numbers. Note the work of a professional machinist....or two...in a professional shop.

You aren't going to order those same parts from Summit, slap it together in your garage, and see those numbers or get that durability.....IMHO.
 
#71 ·
I dare you to build a REAL 550 HP small block (using factory displacement sizes), without a power adder, that drives on pump gas, idles smoothly, and can run power brakes....and then sell it with a warranty.
I wouldn't have used "dare", but agree getting 550hp from a factory displacement sbc, no power adder, smooth idle, and power brakes (assuming without assistance) seems impossible. If you dropped it to 500-525 and allowed 427ci, you might be able to get close, but I think you would still need at least a vacuum reservoir to get brakes.

I would bet that awesome Dorton engine in the video doesn't work with power brakes.

The warranty part would be easy as long as you don't want to stay in business long. :D
 
#76 ·
I thought blue_69_malibu meant running a stock type power brake setup, which is not likely to work with a 1.25 hp/ci motor. I know hydraboost or a vacuum pump can solve power brake issues and agree you can get a 550hp (or 650hp) sbc to idle ok.

My 1st 2 550hp sbc's (383s) probably were <500hp and neither could run a power brake booster.

Maybe Vortecpro can let us know if his 400 can run stock power brakes?
 
#77 ·
The point of this build was to have a real street 500+ SB that ran PB without an electric pump, Hydroboost or a can. to include running A/C. Decent Idle quality came with Marks expertise.

Yes you can build a 550+ SB. Most you see have larger cubes, more compression, bigger cam, bigger carb, larger intake, larger head, etc... and will not naturally run standard accessories without help at 800 rpm and will also start sacrificing bottom end to put it at top for max HP. Sure you can drive most anything on the street. I wasn't looking for a 600+ SB at the cost of a great driver. Most 600 SB are also significantly under this 406 HP and TQ to 4500-5000 RPM just to gain 30 more HP at 6500 RPM and no more TQ. I also didn't want a larger CI SB to push short skirts and high wrist pins in the rings either.

How many SB 406 with a mild cam, low CR and 195 runners run 560hp 540TQ and close to these numbers from 2800rpm and up

Madmanmark,

I'm looking for at a minimum 12" of vac at sea level but should be around 14". Ill let you know this next weekend when I get it in what the exact vac number is.
My last 406 cam XE274H FT (230 INT/236 EXH, .525/.525 (@ .050 with 1.6 rockers) had 12" vac. and ran my PB just fine.

Mike
 
#78 ·
How many SB 406 with a mild cam, low CR and 195 runners run 560hp 540TQ and close to these numbers from 2800rpm and up
Not many at all - Vortecpro seems to have the magic touch!!!

Good luck with the install! If you get pulled over for joy riding, just tell them you're looking for toilet paper.
 
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