# Another 400 build



## Norms68 (Jul 17, 2013)

Hey guys,

Been researching awhile and I want to rebuild the 400 in my 68 GTO.

I’d like to use my parts if I can get away with it.

400 YS block casting 9790071.
TH400 PX tranny with 3.36 gears in Safe-T-Track rearend.
Stock intake casting 9790140.
Service Replacement Quadrajet casting 17054905.
#16 Heads 2.11/1.77, 72cc.
Ram Air 3, D port exhaust manifold casting 9791637 LH and unkown on RH. (will probably replace with RARE ceramic-coated headers and 2 ½” Pypes X-pipe race pro exhaust).

I want a stock engine look and want to use pump fuel 91-93. I street drive mainly on weekends. I don’t need crazy power but would like to drop the hammer on a punk if needed. I think I want to keep the gears the same or similar. I like cruising the highway 70mph @ 2000RPM.

Was looking at 461 stroker. 4.155 bore, 4.25 stroke, 0.023 deck clearance (stock), 4.2 bore 0.062 compressed gasket, 14cc dished pistons, heads relieved to 75cc but I’m still looking at 9.7:1 compession.

Any thoughts?


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## BearGFR (Aug 25, 2008)

As your already know, your biggest problem is going to be your heads. On my first go-round building my 'numbers matching' 461, I ran genuine #722 Ram Air IV heads with 72 cc chambers. I was able to get compression down to 9.5:1, but had to do some really ugly things to the motor to get there. Namely, I was running .075" compressed gaskets and pistons with 20 cc's of dish volume - round dishes, not D-shaped. The astute reader will realize that the combination of these two things _completely destroyed_ the quench characteristics of the motor. I knew that going in, but I REALLY WANTED to run those heads and that was the only way to get there.

Fast forward... after running it on the street for awhile one of those precious heads developed a crack in an exhaust port and after one failed attempt at having it repaired, I pulled the trigger on a good, prepped, street-ported pair of Edelbrocks and also went back to the factory spec head gasket. Result: I'm now back to 10:1 compression (could get away with as much as 10.5 with aluminum heads) but still have the big piston dishes. The motor's making more power than it ever did with the #722's (but it's not nearly as "cool") and the car runs high 11's. My bank account is still feeling the pain.

Moral of the story: I can (and do) relate to the goal of building a stock appearing stroker motor using "correct" iron heads. That's the road I went down originally and would still be on if that one head hadn't cracked. However, if I'd focused a little more on the 'making power' part of the equation instead of the 'looking good' side, the right path would have been to have gone with the E-heads from the get go and build the rest of the motor to be compatible with them. Had I done that, I'd now be making enough power to run low to mid 11's (instead of high 11's) and wouldn't have spent nearly as much cash to get there. Also, FYI, a buddy of mine is also running E-heads on a 455, but his builder (he didn't build his himself like I did) went to the trouble of grinding off the Edeblrock logos on the exhaust ports so after they were painted (I also painted mine), you have to look really close to tell that they aren't factory heads. 

Bear


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## Norms68 (Jul 17, 2013)

Good to know bear. I was trying to save $2k but knowing that I just might have to go big now. The numbers don't match anyway. The engine analyzer shows >500hp with aluminum heads, good cam and exhaust with the stroker. I might as well do it right the first time so I'm happy with the results.


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## Norms68 (Jul 17, 2013)

How does this look to start with from heads back?

Edelbrock 61569 bare heads, 87cc, D-port.
Doug's 590 D-port ceramic headers with 3" collector.
Pypes 10R or 13R (either 2 1/2" or 3"), X-pipe Race-Pro exhaust.

Forgot to mention flat top pistons, cr 10.4:1.


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## geeteeohguy (Feb 2, 2008)

If you stay with the stock crank in your 400, you want the 72cc Edelbrock heads, not the 87cc heads. Also, with aluminum heads, you want to be at 10 or 10.5:1 compression, not a full point lower like with iron heads. I made the same mistake (sort of) as Bear did: I sourced a pair of 'good' iron heads that were the right cc, but ended up spending $1400 fixing them (they needed everything) Hindsight says I would have been much better off simply buying the new E-heads. I'd be making a lot more power, too. Live and learn.


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## leeklm (Mar 11, 2012)

:agree

Add me to the list of "wish I had done that"... Although I do not have much money in my iron heads when building the motor this past winter, I am already thinking a set of alum would be really nice! But at the time, the $2K price tag seemed like more money than it does now. Funny how that works!


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## Norms68 (Jul 17, 2013)

Right. In original post referred to 461 stroker.

4.155 bore, 4.25 stroke, 0.020 deck clearance, 4.2 gasket 0.040 thick, flat top pistons, and 87cc heads will give 10.4 cr.


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## OrbitOrange (Jul 5, 2010)

Why would he need to get the 72cc heads instead of the 87cc with stock crank? I ask because I am researching how I want to build mine and I will reuse stock crank, but adding some H beam rods, and forged pistons.


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## BearGFR (Aug 25, 2008)

OrbitOrange said:


> Why would he need to get the 72cc heads instead of the 87cc with stock crank? I ask because I am researching how I want to build mine and I will reuse stock crank, but adding some H beam rods, and forged pistons.


On a stock 400, even one that's +0.030, 87 cc heads will put you at 8.7:1 if the block hasn't been zer-decked, right at 9:1 if it has. For aluminum heads, that's way too low. Aluminum doesn't hold heat like cast iron does, so you need a little more compression to make up for that difference. 72cc aluminum heads on a +0.030, zero-decked 400 with flat-tops will put you at 10.4: --- which is just right.

Bear


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## OrbitOrange (Jul 5, 2010)

ok so how about a 406 flat tops zero decked with 96s ? Cause thats what I have and I read a TON of conflicting info on what CC chambers make what compression ratio's. seems to be alot of bad info


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## HaloPlayer (Jun 22, 2013)

I used this:
Compression Ratio Calculator - Wallace Racing


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