I bought an engine from a friend of mine, the compresion is around 12.5 to 1 The problem is the 9.4 dynamic ratio with the cam I am using 245,253@.640 on 112cl. the heads are milled to around 52 and the pistons are 5cc relief that were relieved for piston to valve clearance. I don't know wether to get some Trick Flow heads with the 62 cc or get some dish pistons....the heads on it went 10.4 with a little bigger cam, no nitrous 3400 lb car would it be better to get the pistons to lower my compression??? any ideas guys

 

Why are you wanting to lower compression? Is it for tuning, driveability, etc?

I am running 12.2:1 SCR and ~9.6DCR in my 94, 48cc combustion chambers, 246/254 .613/.590 112. Still run pump gas every day.

 

You can easily run 12-13:1 static with the right combination of parts and tuning on pump gas.

 

you can run alot of compression... but 9.4 and 9.6 is really high for pump gas. i dunno about that

 

yes I would like to run pump gas and I was told 9 is the limit on dynamic I haven't tried to run it on pump yet but I do not want to run race gas either or have to mix the two as a band aid

 

New pistons, no gain in HP. (and not cheap) A nice set of done up Trick Flows, more HP. Just my thoughts, if your sure you need to lower your dynamic.

 

these heads are stock casting with the pushrods moved on the intake I have T&D shaft rockers with the intake offset and are set up for my solid roller cam. The tuning done before was on a FAST and the guy said the engine did not like a lot of timing, sign of effecient heads?, so maybe it will run on 93? I have never tried it but don't want to take it all back apart because it detonates after I put it in the car. Thanks ART

 

Those heads must have had some serious pushrod pinch work done to have the need of moving the pushrod.

You could look at a different cam that gave more pumping loss. What head gasket is used? If its a very thin one you could goto a stocker and lose close to a half a point there.

But to tune that high of a compression to work around town in all street driving conditions would take ALOT of trial and error tuning.