64CC Heads vs. Compression
Thread Starter
Burning Brakes
Joined: Jul 2000
Posts: 1,118
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64CC Heads vs. Compression
I want to increase compression into the 9.5 area without changing pistons on this 406ci. Present compression is low, with 76cc stock iron heads, and TRW .160" dished pistons. Cam - 228 @.050 and .480 lift. What would 64cc heads do for me? Pace Performance has some 64cc Vortec heads for the 400 with drilled steam holes that are pretty cheap. They claim .480 lift is max, and I'm right at that number. Too close for comfort? Don't want to dump a bunch of money into this, so the AFR, etc. pricing is not an option. Priority is low end torque. Tnx!
Race Director
Joined: Jan 2003
Posts: 15,175
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From: State of Confusion
Re: 64CC Heads vs. Compression (Chris69)
http://www.smokemup.com/auto_math/compression_ratio.php
I was recently told that ProLine came out with an iron, 50cc head for the SBC.
I don't know the particulars of your maximum-mouse, but 76cc-to-50cc should jump that CR up a bit!
:thumbs:
I was recently told that ProLine came out with an iron, 50cc head for the SBC.
I don't know the particulars of your maximum-mouse, but 76cc-to-50cc should jump that CR up a bit!
:thumbs:
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: 64CC Heads vs. Compression (Chris69)
Right now with a 406/76cc heads/.020 deck/.041 head gasket/20 cc dish pistons you should be at about 8.6-1 compression. If you go to a vortec 64 cc head with the same combination it will put you at about 9.53-1 compression. With the increased compression and the vortec chamber design you will notice a significant increase in power.
The .480 lift limit is because the valve springs retainers can hit the top of the valve guide at about .480 lift. You may want to have a machine shop take .030 or .040 off the top of the guides to be safe.
[Modified by Pete79L82, 4:41 PM 1/1/2004]
The .480 lift limit is because the valve springs retainers can hit the top of the valve guide at about .480 lift. You may want to have a machine shop take .030 or .040 off the top of the guides to be safe.
[Modified by Pete79L82, 4:41 PM 1/1/2004]
Thread Starter
Burning Brakes
Joined: Jul 2000
Posts: 1,118
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Re: 64CC Heads vs. Compression (Pete79L82)
Tnx for the link Glen. Nice site!
Pete... Very helpful. Tnx. The intake runners on those heads are 170cc. Is this about where I need to be? Non Vortec runners all seem to be bigger to 'much bigger', so I get confused with the various head design differences. In other words, why do Vortec's perform so well...
:cheers:
Pete... Very helpful. Tnx. The intake runners on those heads are 170cc. Is this about where I need to be? Non Vortec runners all seem to be bigger to 'much bigger', so I get confused with the various head design differences. In other words, why do Vortec's perform so well...
:cheers:
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Re: 64CC Heads vs. Compression (Chris69)
Just as a side note you have to get a vortec intake to use with the vortec heads so make sure you factor that in there. You might be better off with diff set of iron heads (or even a set of alum vette heads with 58cc chambers) if cost is the bottom line. Check the parts section of the diff forums for used heads, you might find a great deal there.
