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 Pontiac 400 Build 
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Joined: Sat Mar 26, 2005 2:28 am
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Location: Kitchener, On
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Post Pontiac 400 Build
So I am looking at building my Pontiac 400 so I am looking at a few things...
The block is a stock 1975 Pontiac 400...I am planning on having the block honed and bored .30 over and the crank cleaned and polished. The pistons are Kieth Black 133-030 Hypereutectic pistons 4.150 Bore Flat Top with sealed power rings, the cam is a Comp Cam Grind #275 DEH Duration 219 intake 228 exhaust @ .050 lift
.462 .480 value lift RPM 1500-5800, and comp cam Roller rockers 1.65 ratio with 7/16 polly locks as well as a double roller timing chain with advance/retard option...
I guess the big question is, will this set up work with stock 6X heads...They are bone stock heads...
Any thoughts?

I was also given this website to take a look at... ... calculator

1990 GTA
1987 TA (gone but not forgotten)
1976 TA (project)
1995 Z -28 Camaro
1982 Firebird ( my 1st )

Fri Feb 27, 2015 8:37 pm
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Joined: Mon Apr 21, 2014 1:17 pm
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Location: Scarborough
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Post Re: Pontiac 400 Build
If the intake valves are 2.11" and the heads are in good shape (no cracks, valves aren't sunk into the chamber from 20+ rebuilds), I like the 6X castings.

Recondion, port-match, new valve-springs to match your cam, and light up those rear tires. :D


1996 Z-28/SS

Previously - 1996 Z-28, 1989 Pontiac GTA, 1985 5.7 IROC Z-28, 1976 Camaro LT, 1974 Trans Am 455HO, 1974 Z-28, 1967 Firebird Sprint,
1967 Camaro 230 cu-in 140-hp "Blue Flame" straight six with a 2-speed powerglide.

Sat Feb 28, 2015 8:01 pm
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Location: Etobicoke
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Post Re: Pontiac 400 Build
6X heads came in a few variations, so be sure to check the secondary stamp.
A stock 1975 400 with 6X heads came with the 6X-8 large chamber 101cc version.
You will be wanting the 6X-4 @ 94 cc version. ... dspecs.htm

You may want to check out


Sun Mar 01, 2015 4:40 pm
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Post Re: Pontiac 400 Build
I suggest you get the heads flow benched. If you want it ported or cleaned up..flowbench if after and base your cam from the flow chart,weight of car,intake compression etc.You will also base your piston choice from the final chamber size for compression..In BBCs bigger chambers are usually preferred because it unshroud the giant valves.It could also be true for the heads you're picking.

My .02 cents

Sun Mar 01, 2015 11:15 pm
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Post Re: Pontiac 400 Build
Make SURE you run the correct oil in that beast. For break in especially the cam lobes really are delicate so Id run Joe Gibbs break in oil and probably one of his other good options for regular use, or mix up your own.

1987 IROC ww 99 LS1,TR224/112, STG2 heads ported by American Speed, P Gold springs, LS6 intake, SVO 30's, Ported TB, Comp Cromo Push rods, Katech Rod bolts, LS6 oil pump, T56, SW LT's, 8.8 hybrid rear 3.73, 275/40/17 MT ET streets, lots more
12.1 @ 112 mph 1.69 60'

89 R7U 1LE Players Challenge car all stock.

Wed Mar 18, 2015 5:25 pm
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