Needing your help

ok guys I have a 514 its a stock offset ground crank shaft 4.140, eagle hbeam rods ,and srp pistons, bored .80 over it now had cast super cobra jet heads on it they are 72 cc chambers and my compression should be around 12.9 to much compression for the street. Talked to srp they told me i could mill some out of the pistons and take away 17 cc but then id have to rebalance my motor or heres my other alternative i have a friend that has a set of 72 police interceptor heads that he said are 88 cc chambers both these heads have the same size valves in them was wondering how much compression id have with 88cc chamber heads on this and how much power id lose from going from super cobra jet heads to police interceptor heads hes wanting to trade me his police interceptor heads for my super cobra jet heads thanks

http://www.diamondracing.net/cocalc.htm


go here and put in all the specks of your engine with the CJ heads and then put in your combo with the PI heads...



Randy

FIRST - If you need to back-off the ignition timing in order to use pump gas with the CJ heads you will of course lose a bunch of power.
SECOND - Just by lowering the compression ratio the engine would lose power IF it used the SAME heads, when run with appropriate fuel.

Unless you plan to run race gasoline, then using the P.I. heads at maximum efficiency is the best option.

i know the super cobra jets are a more desired head but ive also head good results on 72 police intercepto heads both these heads have super cobra jet size valves in them if the compression was the same would i really be losing that much power with the PI heads over the cobra jet heads? this motors going to be used for street and some strip also was looking at the dollar wise like dishing my pistons and rebalancing my rotating assembly when just switching heads would cure my problem, just dont know how much horse power iam going to lose between the 2 heads

I've never SEEN a set of the interceptor heads. But,I thought they were small CC heads.

bbf-falcon wrote:I've never SEEN a set of the in
terceptor heads. But,I thought they were small CC heads.

No Rick, the 1972 chambers are usually in the high 80's. (D2OE-AB)

i dont post here much but iam here all the time and needing your bleed ford blue thoughts

Nothing has changed from my oppinion in a post earlier in this thread.
Especiall for a street driven car with an exhaust system.

rmcomprandy wrote:

bbf-falcon wrote:I've never SEEN a set of the in
terceptor heads. But,I thought they were small CC heads.

No Rick, the 1972 chambers are usually in the high 80's. (D2OE-AB)

Thanks Randy, Like I said i've never seen a set,Learn something everyday