shaving PI heads

The worst feature about the PI heads is the limited PTV clearance. Shaved heads would only make that problem worse. It would also create problems with trying to time the cams as the increased slack in the chains would throw it off.

Why not get a salvage Mark VIII engine and do a mild rebuild? With the 3cc pistons in the Lincoln engine and PI heads you have somewhere around 11:1 comp. Also with a rebuild you'd have the opportunity to have the pistons notched with valve reliefs allowing a more aggressive intake cam profile.

I understand... I'm kind of in the same boat. However, a freshened up aluminum engine + PI heads + stage 3 cams would drop weight and provide an awesome flat torque curve with well over 300 RWHP. Good luck... One day I'll do a nice N/A build like this.

bhuff30, you could go with thinner head gaskets. If you're gonna pull the engine then you could also just buy some Mark VIII/Cobra rods and pistons. I've seen them for around $50-$100 used. Fresh bearings, rings and seals and you might spend about $250 total (including price for rods and pistons. You can even look online for people who bought rings, seals, bearings, etc and never used them. All said and done you could probably get away with spending around $200, getting a pretty fresh build, and a CR of over 12:1.