How Much Can Heads Improve Compression???

Kraykuda; have read enough of your posts to choose between the two available heads for better compression and considering that the rest of the car is a 904/3.55 cruiser, the best way to go IMO is with the 273 heads that should be revisted, checked out, and installed after you cc the head and re calculate the ratio with a possible milling of the heads to get your 9.0-1.

Flow testing the head and re porting it maybe an option to maximize the combination. The heads port windows and flow rates could possibly be improved over what you have now to allow better performance and effeicency out of the mill. On other 273/318 heads, the port windows have been able to be opened up to 340/360 size with good flowing ports. While the small engine head will not port out to whopping numbers, it will flow better (more) than a stock 340/360 head and maintain excellent velocity.

If your not going back into the engine, then the head is the way to go.

I would NOT try to zero deck that engine with the low compression slugs inside there now. The problems that develop with heavily milled heads and heavily deck blocks come into play to cause headaches and havoc. If you need a high compression engine, it starts with proper pistons followed incunjunction with the cylinder heads and then head gaskets.

I didn't see what came you have available, but I would error on the small side with the above intended drivetrain combo. To be honest with you, the replacement upgrade 340 Purple cam performs really well with the intended combo. New modern cams should provide a better driver and running engine.

In terms of duration @.050, I would not go past 230 but stay under that number.