black6gen

Ok i forgot wich one flowes better for boost, the Z6 head or the Y8 head?

Also when it comes to building one for a higher reving setup what parts and work would be recomended for the head? I plan on taking it up to about 8k.

Iceman05

both flow about the same, but for boost, the Z6 is MUCH better, the combustion chambers are designed in a fashion which does not hold heat like the Y8 chambers. Therefore the Z6 head can run more timing. Any aftermarket valvesprings will allow for 8k operation with no problem.

EDIT: The Y8 intake mani is much better flowing than the Z6 mani. Use a Y8 mani on a Z6 head and you're golden.

sohc_mshue

Well i wouldn't necessarily say the z6 head holds heat better than the y8 head. The y8 head has better quench area on it which actually helps to promote a faster more efficient burn in the combustion chamber which helps prevent detonation. This in result of course requires less timing due to the faster burn which isn't necessarily a problem. The z6 ports are suppose to flow better though particuarly in higher power applications.

vtecking93

use da z6 head because heat doesnt build up as much as da y8, but use a y8 mani

CavemanRacing

The y8 head with the proper port work will oust the z6 head. I have no numbers to back this up, I base this on it making my car faster.

Iceman05

listen to matt, he knows his shit. I completely forgot to mention the differences in quench area...

black6gen

Ok so i should go with the Y8 with upgraded valves,springs,retainers, and cam. Now as far as port and polishing, are there any specifics on this?

99EJ6T

got proof of this?

not trying to be a dick, but i have seen this posted many times. but no one seems to have flow bench proof, the best i have seen is a cut away of both manifold plenums. the guy that posted it however, did not have any measurements with the pixs. as he posted them for the correct way to port a intake manifold.

stay with a stock cam. they will make better power then most aftermarket cams (due to the drop in duration).

also a P&P on a d-series head is not required. most d-series motors (sub 400 whp) will not see a gain from this. however if the P&P is very aggresive and your goals are in the plus 500 whp range, then go for it. but a stock y8 head is good for about 450 whp @ 24 psi with a 57 trim t3/t04e. <- fast2cam (403 whp) on H-T / 1992si (iirc, 560 whp) on d-series.org (he did the research on the p&p on a d-series head)

sohc_mshue

The zex 105300 or 95300 cams are superior to the stock cam. Its been proven. I never dynoed my boosted sohc with the stock cam, but the 59300 made a huge difference on the butt dyno.

Iceman05

105300 FTW, much better mid and top end. I would personally go with the Z6 head though....