Hemi Advise

I'm changing the set up on my Alcohol 480" Hemi. 8/71 std helix. currently 11.0/1 compression. Blower makes 21lbs boost at 8500rpm

Need advise on:

1) Maximum static compression ratio I can use?

2) Minimum safe valve to piston clearence?. Currently have .200" on Exhaust and .250 on intake" Can I go as close as .150"?

3) Recomended valve spring pressures.?
Cam is DUR 338 degrees. = 297 degrees at .050".
.700 valve lift and 112 degrees
Currently using a Crower spring with 1.950 installed height. 300lbs on seat. 800lbs open....think I need more pressure?

Thanks
Dave

 

check your pm

 

Still seeking advise on valve to piston clearence and max compression ratio for 8/71 blown Hemi....

Cheers
dave

 

Dave, I run .175 on my exhaust and .150 on my intake and I have not had any problems at all with this clearance. Arias pistons advised this clearance when I purchased the pistons and I do run alloy rods.

One tip though, check this clearance with a light spring and then install your race springs and check the difference.

I also run the 1.950" installed height spring but at 360# on the seat.

If your class allows it, change the blower to a 14/71, even if it's a std style blower, mine is and it makes 45# @ 9200 rpm with 11:1 static comp.

I run an early stage V style KB.

Cheers Ray