Good Head/Bad Head Question?
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Joined: Nov 2007
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From: Hockley Texas
Good Head/Bad Head Question?
I was given a set of alum. heads (#12367712). I do not know anything other than the parts exchange description."Fast Burn"alum. 210 cc intake port,2.00/1.55valves,62cc chamber. My 77 L-48 heads are open chamber(72 I think). The Fast Burn are slant plug. My question is 1) are they reverse flow 2) will they work on my L-48 with a EB RPM manifold,3) will my compression ratio be approx.9.5, 4) wil I have problems with the slant plugs and headers?I have stock manifolds now. I already have a cam that you guys earlier told me,was a little too much for the L-48 low comp. set up. I'm only looking to increase the compression and let this motor perk up a little while I begin collecting my parts for either a 383 or even better a 406 WP block set up. I just want to keep driving this one for a while. It is a fresh motor. Any experience/information with these heads would be appreciated. I went to the Houston Vette Expo and was kind of disapponted. Thought more venders would be there.
Flatop
Flatop
Race Director
Joined: Jan 2003
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From: State of Confusion
..... in mid-'07, Chevrolet High Performance Magazine used Fast-Burn heads on a 290-HP crate motor with an RPM Air Gap intake (can't imagine them being reverse-flow ), with a 650 Holley double-pump carb, 270H cam, etc., and made almost 400 HP, and over 400 ft/lb of TQ:
I'd think your squeeze would be approx 9.4 - 9.6, and wouldn't venture a guess as to header-fitment issues.
I'd think your squeeze would be approx 9.4 - 9.6, and wouldn't venture a guess as to header-fitment issues.
Le Mans Master
Joined: Mar 2004
Posts: 7,465
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From: Little Rock AR
A#1 - Standard cooling flow heads, not reverse flow.
A#2 - If you can close the hood, you should be able to use it. The port roof on those heads is raised so you might want to be aware of that. It might affect your decision.
A#3 - 10.6 C/R was my first calculation based on a few bad assumptions. Maybe you have dished pistons and less compression - 9.something to 1 is probably right.
The exhaust ports are also raised. You can weld the header bolt holes closed and redrill them in a different location so that is pretty do-able.
Hope this helps,
-Mark.
A#2 - If you can close the hood, you should be able to use it. The port roof on those heads is raised so you might want to be aware of that. It might affect your decision.
A#3 - 10.6 C/R was my first calculation based on a few bad assumptions. Maybe you have dished pistons and less compression - 9.something to 1 is probably right.
The exhaust ports are also raised. You can weld the header bolt holes closed and redrill them in a different location so that is pretty do-able.
Hope this helps,
-Mark.
Last edited by stingr69; Feb 19, 2008 at 06:48 AM. Reason: flat top assumption wrong
Burning Brakes
Joined: Aug 2006
Posts: 1,155
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From: San Diego California
Definitely not reverse flow- their not 92-96 LT-1 heads. Your CR should be no more than 9.8 with the new heads, which should bolt on, if you now have the factory L48 76cc 8.5CR iron heads and factory dished pistons. You're gonna be real close on closing the hood with that manifold and a stock air cleaner. The 210 heads are pretty big for the street- 170-185 would be better for low- mid RPM"S for a street car.
Melting Slicks
Joined: Aug 2004
Posts: 2,906
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From: Oakbank Manitoba
The heads are dual drilled for vortec and standard bolt pattern intakes. Your current intake will not work with these heads as the runners are taller. You must use a raised runner type intake made for these heads or a vortec intake.
