I am trying to get an Idea of The ball park compression ratio of my motor,The guy I bought the car from didnt build the motor,The Guy before him did.I did manage to get in contact with him...He told me that Munching(Sp) Machine shop Build the motor,But he has since closed up his shop in Northern NJ.

He was only able to tell me the cam specs,That the pistons were 10.5-1.

Now with the open chamber 049 heads...I know that the comp.ratio Should drop.

Im not sure if the cam would play a role in the equation or not..But it is a Crane 134571 .571/.585 Lift 246/254@050 Duration Cam timing at 050 is as follows;

Intake 16 BTDC 50 ABDC
Exhaust 64 BBDC 10 ATDC

I am considering putting a procharger/Or Turbo on the car...But I want to make sure Of my Compression ratio first.

Any help would be greatly appreciated.

Thanks,Shawn

This is a very common problem; unless you built the engine yourself, or have all the documentation, you really dont know what you have. Just because they're 10.5/1 pistons doesn't mean anything...the combustion chamber size will dictate your c/r, along with the head gasket, deck height,etc. Your cam will determine what your dynamic (running ) c/r is. I dont know much about forced induction, but I do know that you dont want as much overlap. You want to keep the charge in the cylinder, and not have half of it blow back out due to overlap. Most blower cams are pretty wide in LSA, usually at least 112*, frequently more. Duration is dependant on the rest of the build. What heads are on the car now? 049 heads are generally around 118 or 119cc, and with flat top pistons or a very small dome, you would be in the right range for a blower of some sort. But if those pistons are rated at that c/r with a 119 cc chamber for example, you'll be too high for forced induction. What you are going to be faced with is measuring everything when you pull the engine apart. You have to know what you have there before you know anything for sure.

Thanks for the reply...

Yes,There are 049 Heads on the car now...I think for the time being that I am just going to throw a 100-150 shot on it...The guy told me that's what the engine was built for to begin with..With the intention of hitting it with nitrous.

Thanks Again,
Shawn