ORIGINAL: RLSH700
Did you build this engine from scratch or did someone do some of this stuff before you got it? Why don't you have the 10.4 to 1 pistons or the "good heads?"
my dad is a dodge mechanic who has spent lots of time around muscle cars, and he put the motor together. when i bought the engine when i was 16, it didnt come with pistons or heads. J or X heads go for a premium now, and the higher the compression the piston, the better quality/brand the piston, and the higher the price. at 16, i simply couldnt afford to shell out big money for J or X heads and good pistons...so we bought the cheapest pistons and rings that we could find. my dad didnt want me to get into street racing like he did, so he put the motor together to not run all that great, but once i proved to be responsible with it, the real build began. its nice, because i can run 87 octane, and it still runs well. my engine runs as well as it does because my dad is smart with the engines, and i try to pick up things from him. without him, i would probably drive a yugo or something...
71 chally, the problem with cutting the heads is that you then have to cut the manifold, or it wont line up. also, depending on the type of pistons, the size of the cam, and valve to piston clearance that you have, the amount that you can safely chop off the heads changes. before we chopped my heads, we consulted a friend who works in an engine shop, and he told us what he felt that we could safely chop. alot of math involved...
for head gaskets, we are running the thinnest copper gaskets that we could find..i think that they were from MP, but its been a while.
here is how low the compression on my engine was with the old, unchut heads. at the time, i was running high 13s. we were working on the car at the shop, hurrying to get it ready for an event, and one of my dad's buddies was "helping"...
he took the air cleaner off, and told us that he dropped the wing nut under the car somewhere...when we couldnt find it, he told us that he knows that he heard it hit the suspension, it must be caught up under the car somewhere. well, once the work that we were doing was complete, we fired it up to load it onto the trailer. he had started the engine, and it ran just fine,and had pulled it out of the bay when a different (more competitant) friend told him that something didnt sound right. with it running, he got out and listened, and quickly shut it off...we tore the engine apart and we found the wing nut...in the number 1 cylinder. it was sitting on top of the piston, and the compression was so low that in the few minutes that it ran, it didnt even crush the wing nut flat! it didnt damage the valves or the piston, and it barely scratched the top of the piston. now, that was with the old heads, and the new ones are cut, but i dont recall how much.