318 Port match heads to Performer RPM Intake
The air gap manifold seems to be a mismatch to the rest of the combination. That’s a higher rpm manifold on an engine that Likes low end torque.
Ive done this before and with very good results. The intake starts making more power a few more rpm up the scale than the Performer and the like. BUT, unless you have steep Hwy gears, not only will you not really notice much at all but you’ll also just simply buzz through the first few hundred rpm quickly. I know this from the LD-340 as well as the RPM-AG. It’s nothing...
the air gap seems to be more of a manifold for high compression, higher duration cams, 360 heads, and makes power more at the top end. You can’t really have this well without over 9:1 compression at least
This is not true. In truth, the Performer and the RPM are both really excellent down low. The Performer just gives up on top a wee bit in HP and total usable RPM.
A performer manifold if fine but I would like to see the ld4b or it’s copy cat weind action plus. The performer seems to be like a stock 4 barrel
The Performer is just like the OE 4bbl. And does very well. Not really any better or worse than the factory OE unit. The Weiand Action Plus and Stealth fall in between the Performer and the RPM. Having all of these intakes at one point, they all did well.
Most people give the Performer and the stock OE 4bbl a unfair bad wrap and a handicap without merit. There really is t a reason you can’t pull 400+ HP out of ether or these intakes. Never mind a porting.
In my research of building the 318 and my current build I find that
Whiplash or xe262 or similar with low compression
4 barrel
Dual 2.5 exhaust
Ported heads matched to intake
Action plus or ld4b
that’s close to the best combination a low compression motor can get
also the thin head gaskets and .030-.040 taken off the head.
That kind of set up is a good one. It skips expensive rebuilding (if it s not needed of course) and pistons. As high school kids and early 20’s, a lot of us did that. It helped the handicapped smog era mills pretty good. Not great, but it worked well enough.
I’ve wondered lately if the stock 68 318 heads are as good as the 302 Heart shoes heads for low compression engines
Good question. Search the threads! There was a discussion on this very thing not to long ago.