Manifold dilema
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Joined: Jan 2004
Posts: 535
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From: Darwin, Australia NT
Manifold dilema
This is a common problem, I see various threads on this. Im running a 1970 vette with stock hood and a rec port BBC. I dont want to change hood or heads but I'm sure I should be changing my low rise LS6 manifold.
They are a sad looking design. The tall port size mean runners have to drop deep into the valley before turning up then a hard bend down into the port. The only other rec port manifold Ive seen that would fit is an offenhauser twin 4 low rise single plane. Down side is the low end torque is poor.
Rest of my motor is std bore 454, 12/1, 238/244@112 hyd roller, 950 holley, thorley 2" headers into twin 3", pocket port and port plates. M21 with 3.7 rear. At a later stage Im thinking of trying to shovel a centifugal blower in as I have 8.75/1 pistons.
If I had oval ports, an Edelbrock Torquer and possibly a Holley Street dominator single plane would fit. Both of these manifolds (if modded with port extensions) would have to be better than the LS6 manifold. Im particularly keen on the Holley if I can find one though I already have a Torquer in the shed.
Is anyone running a oval port manifold on a rec port head? Ive read somewhere that it was good for heavy cars. Im worried about the manifold not sealing at the top of the port. I could have a friend lay extra aluminium here as I will have to have manifold milled due to angle milled heads.
Any opinions? particlarly on the Holley Street Dominator (Ive got a SBC version and loved it)
They are a sad looking design. The tall port size mean runners have to drop deep into the valley before turning up then a hard bend down into the port. The only other rec port manifold Ive seen that would fit is an offenhauser twin 4 low rise single plane. Down side is the low end torque is poor.
Rest of my motor is std bore 454, 12/1, 238/244@112 hyd roller, 950 holley, thorley 2" headers into twin 3", pocket port and port plates. M21 with 3.7 rear. At a later stage Im thinking of trying to shovel a centifugal blower in as I have 8.75/1 pistons.
If I had oval ports, an Edelbrock Torquer and possibly a Holley Street dominator single plane would fit. Both of these manifolds (if modded with port extensions) would have to be better than the LS6 manifold. Im particularly keen on the Holley if I can find one though I already have a Torquer in the shed.
Is anyone running a oval port manifold on a rec port head? Ive read somewhere that it was good for heavy cars. Im worried about the manifold not sealing at the top of the port. I could have a friend lay extra aluminium here as I will have to have manifold milled due to angle milled heads.
Any opinions? particlarly on the Holley Street Dominator (Ive got a SBC version and loved it)
