Shortblock or Heads.......

[6D9]

Here is the deal...I just got my current set up up and running. Its a 408 sbc with a D1SC Procharger. This is a 90% street car 10% strip. My current set up is right at 9.88 to 1 comp. The shortblock was never designed for boost but I figured would work ok. Here is whats in it:

GM 2 bolt 400 block.... .040 over
Eagle cast steel crank
Eagle 5140 I beam rods...arp bolts
Probe forged pistons...-15 cc dish

My current heads are AFR 195's. They flow around 260 at .550 lift and have 68cc chambers. If I swapped the heads to some AFR 210 Eliminators with 75cc chambers this would drop my comp ratio
down to right at 9.19 to 1. I figured my comp would be ok but kinda worried about the strength if I turn the boost up to 10-12 psi. But...I have seen alot of other on this site have decent luck with similar built shortblocks.

My other option I was thinking was build a boost prepped 383 short block and keep my current 195's. You can get them pretty cheap with some decent parts. I was thinking something like this...

4 bolt 383 sbc........8.5-8.8 to 1 comp ratio
4340 scat crank
4340 scat h beams..arp bolts
Forged Mahle coated pistons

Thoughts????

[4OfaKind]

Rebuild the block. Every project must start w/ a solid foundation. Cast cranks and I beem rods don't work well with high boost levels. Eventually you will end up rebuilding your bottom end due to boost addiction, so do it now.

Mal

[6D9]

Mal...thanks for the reply! I dont plan on doing any changes right away but maybe after the summer. I will keep the boost levels down and timing pulled out while on pump gas. Just gonna have a little fun for a bit.

[ItDoRun]

Might as well do it right the first time and build the forged bottom end. Not to say it won't be fine like it is with low boost, but after the boost addiction sets in, you know what the end result will eventually be.