I recently went all the way through an ls bottom end and we had the block decked to make it all nice and smooth (only took .005 off). My main concern now is that the pistons (9.5:1 cp pistons) are almost 0 decked. I dont have a dial indicator at the moment to check it, but what is acceptable piston to head clearance? I've searched all over the place to find it.

I just assume that the .030 h/g will make it plenty of clearance, but I dont wanna chance it. Thanks for any help.

 

which head will you put on this bottom?
1.5 mm should be enough

 

5 thousandths is nothing. i wouldn't worry about it with 9.5:1 (relatively low compression) pistons and stock cams. if you want to feel good about it, clay it.

 

The closer the piston comes to the head the better it will run, but the looser the piston is in the bore the more you need, higher rpms you need more, etc.

So far we haven't had any trouble with 0.030 to 0.040" clearance.

 

Well this block has been decked before, for sure. Its not hitting the machining marks on the block though. I know the h/g will add prob the clearance I need. Im just kinda anxious.