Head cc
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Head cc
I have a 302 from 1976. I'm not sure what the cast number for the heads are and I don't wanna take the motor apart if I don't have to. I wanted to know what cc the combustion chambers are. I know the heads have pressed in rocker studs (not screw-in.) Thanks.
Erik
Erik
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Realy thiers no telling what cc they are just by a date of the block or vehicle, someone else could have put other heads on it, other than that date time. The only way to know is pull 1 and get the casting numbers and be down with the guessing. Other than that someone could tell you 62.00 cc's and then you find they are 69.00 cc's, see what I'm saying. Unless you absolutly know for sure it's all original, then that may work for getting a ballpark cc size.
EDIT: OK,, just looked for that yr also and 67.50 cc is probably what they should be, but like I stated above it's a guess to what heads is on your 302 motor.
Steve
EDIT: OK,, just looked for that yr also and 67.50 cc is probably what they should be, but like I stated above it's a guess to what heads is on your 302 motor.
Steve
Last edited by luvinfords; May 18, 2005 at 06:08 AM.
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I understand that I know for a fact that they are 76 heads. We looked up the numbers two years ago when we rebuilt the motor. I just wish we had cc'd the chambers. So do you think that I will gain much by goin down 5cc's. The E6SE heads have been milled so I feel that I definately will lower by 5cc's.
Erik
Erik
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If they have been decked then you pick up a cc or 3-4 . CC' them and see what size they are, that will let you know what they accually are. And yes, if they have been decked 5 CC's then they should be round...62.50. Steve
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From: Tucson, AZ
united engine and machine has a compression ratio calculator on their web site. they have been making pistons for a long time. cylinder head volume is one variable in the formula. cylinder bore, piston volume and deck clearance along with gasket thickness and diameter are other values needed for accurate comp ratio calculations. i just used the calculator with 0 deck, 4.1 inch diameter / 0.04 gasket thickness, 10 cc piston volume, 4.03 cylinder bore diameter. going from 67.5 to 62.5 cc combustion chambers will increase comp ratio by 0.4 - 0.5. if you have better numbers, use them. but this should get you in the ballpark. cheers, garsten
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I have Desktop Dyno 2000, which has a compression ratio calculator, but thanks anyhow. If the heads currently on the engine have 67.5cc combustion chambers and the E6SE heads have 62cc cambers then I should have lost about 6cc's (This is because the E6 heads have been milled.) That being said according to the Desktop Dyno calculator, I'll gain 1.25 on the compression ratio ie... 8.0 to 9.25 with the head swap. I might just go ahead and do this. I might be able to get my hands on some E7 heads but that's kinda in the air. Thanks alot for all the help. If there is something else that comes to mind or you wanna comment on the math let me know. I'ld rather be wrong now then when the engine is done.
Erik
Erik
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