Selecting a manifold for AFR 265's - single versus dual plane - thoughts anyone?
here we go.
Winter drags on and on......
02-26-2014 | 10:00 PM
#82
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Joined: Dec 2008
Posts: 387
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From: Tampa, FL
I don't get it. Looks like you ported the heads to a standard intake manifold - ie: one with intake to head bolts between each set of runners. Where these bolts are, but your heads don't have them, is a very high flow area. Thus, why most aftmkt heads don't have this bolt hole.
In fact, on intakes that do, you need to tap and plug that holse so it won't be open to the runner.
Anyway, as far as dual planes go, 70% of the power to be gained by these are in the plenum - mostly transition from plenum to runners. Yeh, hard to get to on lower plane. And in the more pronounced curves on the runners. Sometime you have to whole saw these areas open to access this. Kinda overkill for most I/O builds, but atleast most 496+cid engines better utilize a smaller (Vic Jr/ Dart 4150, or etc) single pane intake anyway. Many 540+'s can utilize a 'medium' size single plane like a Victor 454R or etc.
In fact, on intakes that do, you need to tap and plug that holse so it won't be open to the runner.
Anyway, as far as dual planes go, 70% of the power to be gained by these are in the plenum - mostly transition from plenum to runners. Yeh, hard to get to on lower plane. And in the more pronounced curves on the runners. Sometime you have to whole saw these areas open to access this. Kinda overkill for most I/O builds, but atleast most 496+cid engines better utilize a smaller (Vic Jr/ Dart 4150, or etc) single pane intake anyway. Many 540+'s can utilize a 'medium' size single plane like a Victor 454R or etc.
