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Can anyone tell me if I can get 11.5-1 cr with flat top pistons
and 4V closed chamber heads?
 

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yer you can but you will have to deck them down a fair way and on the edge of the heads where the big water jacket is they get thin and tend to leak water. Just run a 0 deck and see how many cc you have in your heads tell me and ill work it out if u need a hand. also the cc of the piston valve reliefs
 

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Std 4V CC give you 10.5-11 anyway. It's a lot of work for not much. If you are going to run AV Gas or whatever you may as well run 12.5 or so and go beserk with the motor
 

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I agree with what xacoupe said... I think the most you can run on premium unleaded petrol like Mobil Synergy or Optimax is 11 to 1 and that's with a big solid cam... and even then I think you might need some sort of a octane booster.
 

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Munch Munch Rice 4 Lunch
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so what sorta compression ratio would you get with 302 heads on a 351 motor?
 

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74 XB Fairmont
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qwikcorty said:
anyone know how many cc's the std valve reliefs are?
I can't remember seeing a stock domed valve?? I've seen aftermarket domed valves. Usually the valve relief is 1-2cc's.

REVHEADRON: At least 11:1 with 302 closed chamber heads.

Brenden
 

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Um you guys way off here. Std 4v closed chamber heads 68 cc. The valves reliefs in a flat top trw foe example are 3 cc each
 

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It's been a long while, but from memory the chambers on my old phase 3 were 62 or 63 cc, and that was after polishing. What figures here???

As Maniac said, aftermarket pistons usually figure around 5cc or 6 cc, so i'd guess 4 or 5 cc for a standard piston.
 

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Ive had 4vs down as low as 56 cc but like isaid they get real thin on the water jackets at the end of the heads so try avoid it.
 

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Im building a motor for my coupe at the moment. Im using a 351 C crank, 302 rods, with 351 ACL flat tops on 2V heads, thats giving me close to 11.5:1 comp.
 

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Standard 4v is not 11:1 there not much over 10:1 if you do the math.
std replacements are 3cc
std cc about 68
never heard of 4v down to 56cc, how much did you take off?
how many cc are the 302 heads?
 

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slaves wage said:
Standard 4v is not 11:1 there not much over 10:1 if you do the math.
std replacements are 3cc
std cc about 68
never heard of 4v down to 56cc, how much did you take off?
how many cc are the 302 heads?
There was to options/chambers for the 302C closed chamber heads it was either 56 or 58cc and 64cc.

Brenden
 

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MoNoXiDe said:
Im building a motor for my coupe at the moment. Im using a 351 C crank, 302 rods, with 351 ACL flat tops on 2V heads, thats giving me close to 11.5:1 comp.
2v closed chamber and 4v closed chamber arent the same dude incase you didnt know. NICE COUPE BTW!!!!!!!!
 

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Maniac said:
Um you guys way off here. Std 4v closed chamber heads 68 cc. The valves reliefs in a flat top trw foe example are 3 cc each
68cc ummmmm very rare mine stock were 64cc ended up at 62 after shaving on average 66cc and under thats all ive ever seen but ford was all over the place with these.
 

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it's me said:
68cc ummmmm very rare mine stock were 64cc ended up at 62 after shaving on average 66cc and under thats all ive ever seen but ford was all over the place with these.

Ive had a few sets to service from Fords and your right they have ranged a little but the norm is 66 to 68 cc.
 

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Hello,

I'm in the U.S. , new to this forum. Just like to add what I know( just a little). This is all american stuff so if it doesn't apply just tell me to piss off. The smallest 4v chambers were the D0AE castings that came on 4v motors for 70. The next in line were boss351 heads. The D1AE castings were the next biggest those were the 66-68 cc heads. Then it went to the open chamber 4v at 76-78 cc.

With a flat top and the small D0AE castings it'll come close to 10.5 to 1. You would have to mill the heads on this combo pretty good to get to 11 to 1. So I don't think getting anything close to 11.5 will be easy. With the old trw pop-up it is just at 12 to 1. That's with the smallest chamber. The bigger chambers will be less.

Nice to meet everyone,

sixty4fairlane
 
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