J head question again

I did a search and couldn't find what I need so here it goes again. I'm buying a J motor and want to use the head on my 78. I know about the cam chain parts for the conversion. My question is what pistons do I need? I want to have around 1200cc. If I get the blower that I'm planning on should I use the old style 1200 pistons with a 10.5 to 1 compression or the J pistons with 10.5 to 1 CR? Or the old style 12 to 1 CR? Not sure how much boost the blower will make but I'll find out soon.

have you even got the blower yet? dont play your cards out till you got em.

I'm hoping to go over this weekend to take a look at the set up he has. I guess I could just ask him what to do. He has been running superchargers for years and has it down to a science.

If you run the old style pistons the CR will drop 1-1.5:1 from what they should be with a Kz head. That'll put you around 9:1-9.5:1CR but I don't know what kinda squish area you would have.

I would get low CR pistons made for a J model head/Kz block. You could run 10.5:1 pistons but you're gonna have to keep the boost really low to keep detonation at bay or you're gonna have to retard the timing...ALOT.

Later, Doug

for my 1385 turbo project i just bought 10.25:1 kz pistons which will will bring you down to around 8.25:1 with j-head;)

Don,

Oh sure.....N/A isn't fast enough for you...you have to get all silly with a supercharger...

I agree with streetfighter...

Larry C