Will Eddy 84cc RPM Heads lower or increase my 10 to 1 compression 440 engine?

[1Bad70Charger]

And those opinions Bob are extremely valued given your credentials as a professional race car engine builder, and I REALLY appreciate you taking your time to write up such great information that you obviously put alot of time and thought into!  


Thank you kindly as I certainly want my current 440 build up to be very reliable and as close to bullet proof as possible (so this is GREAT info to have) thanks again!!!!

[Lifsgrt]

Recommend you pull the heads off the motor and measure exactly what you have before you start milling perfectly good heads.  You might want to consider installing the Eddy heads as they are, and changing the cam to one appropriate to that setup.  I believe if your engine is built to stock specs, the pistons may be down in the hole quite a bit (.080" or so).  Too much distance here can cause detonation problems if you raise the compression too high.  That is, for a pump-gas motor, you want to keep the quench height reasonable.  .040" between the piston and head is about as close as you'd want to go IMO, don't know the max recommended off the top of my head.  I bought an engine that needed work a while back, which was "built to six pack specs", and sure enough the forged six pack replacement pistons were installed about .005 in the hole.  If you put the Eddy heads on this motor with a .039 head gasket, that makes for a great setup.  Runs good with the stock iron heads as well.  Just my    Good luck!

[1Bad70Charger]

Recommend you pull the heads off the motor and measure exactly what you have before you start milling perfectly good heads.  You might want to consider installing the Eddy heads as they are, and changing the cam to one appropriate to that setup.  I believe if your engine is built to stock specs, the pistons may be down in the hole quite a bit (.080" or so).  Too much distance here can cause detonation problems if you raise the compression too high.  That is, for a pump-gas motor, you want to keep the quench height reasonable.  .040" between the piston and head is about as close as you'd want to go IMO, don't know the max recommended off the top of my head.  I bought an engine that needed work a while back, which was "built to six pack specs", and sure enough the forged six pack replacement pistons were installed about .005 in the hole.  If you put the Eddy heads on this motor with a .039 head gasket, that makes for a great setup.  Runs good with the stock iron heads as well.  Just my    Good luck!

Thank you for your advice I appreciate it.  As it stands now I am not planning on milling my brand new Eddy Heads and the engine is coming out and will be completely gone through and after pulling off the heads and determining how low my compression is, the desired compression will be obtained by completely rebuilding the shortblock also with proper forged pistons. 

That is the lastest update where I am it and most likely the entire engine is going to be rebuilt into a hi perf 10:4 to 1, pump gas, street ground pounder, that should make in excess of 500 ponies and torque!