nrthbamaz28

I'm going from cnc ported 706 head with 2.02 exh. To ported 243s milled .030 with 2.02 1.60s ... am.i gonna be dissapointed or should I expect a decent power gain. 02 ls1 stock bottom end. Also went bigger pump and inj. Was on stock inj

96capricemgr

iTrader: (1)

Depends on the quality of the port work in each.

CNC porting should be consistent but the port quality is still largely dependent on the hand developed master port that was measured to start the cnc programming.

Some shops put a lot of time into master ports and let the machines run slow for max quality, other's use cheap machines and just aim to cleanup the as cast look in the port, same goes for hand porting.

Darth_V8r

iTrader: (4)

243 are generally worth 20-30 over 706. Ported 243 are generally worth 20-30 over ported 706. Only exception would be if a freaking really good porter did the 706 and a crappy ported did the 243.

You should have the 706 flow tested. If they are flowing in the 280's or better at 600 lift, might want to just skip to aftermarket

HCI2000SS

iTrader: (2)

If both heads are ported by the same person there will only be a very small difference in favor of the 243's. Like mentioned above the it's really going to depend on who does them and how they flow

redtan

iTrader: (5)

I imagine you won't get that much power, definitely not something you will notice.

But again depends on who did the 5.3s and who's doing the 243s.

nrthbamaz28

Maybe I should of just skipped to aftermarket then. I'm swappi ng my cnc 706 head with 202 and 155 to a full hand ported and milled .030 243z with 2.02 1.60 valves. I'm just not wanting to be disappointed

nrthbamaz28

I'm also going from stock fuel system with stock inj to a 36lb inj with the racetronix kit and from a junk midwest converter to a ptc 3800

HCI2000SS

iTrader: (2)

I seriously don't think you will see much of a difference. Maybe 10 hp or so. I could be wrong though

nrthbamaz28

Oh well... It's already done. Maybe I should sell the 243s and 706s and buy some afrs....

HCI2000SS

iTrader: (2)

A good set of aftermarket heads by AFR, Mast, Trickflow, etc...will make a fairly good difference but then again you will pay a premium as well

Darth_V8r

iTrader: (4)

And so goes the addiction...