Intake advice - exhaust crossover

[Johan]

I'm putting on a new Performer intake, and I noticed that the new gaskets are not cut for the exhaust crossover. Will I gain (or loose) anything by blocking off this? I assume I also have to add some sort of metal blockoff over the head opening, or the gaskets will just burn. If I add some piece of metal, I guess it has to be very thin, or the intake will not sit flat against the head surface. I was thinking just a piece of aluminum soda can or so, but I admit it feels a bit "bubba".

How about the choke (coil type), will it work if I block the crossover?

 

[Crimson Thunder]

Since you live in a cold climate I wouldnt block it off.Just take a razor blade and match the gasket to the crossover port.

 

[Jack]

I'm putting on a new Performer intake, and I noticed that the new gaskets are not cut for the exhaust crossover. Will I gain (or loose) anything by blocking off this? I assume I also have to add some sort of metal blockoff over the head opening, or the gaskets will just burn. If I add some piece of metal, I guess it has to be very thin, or the intake will not sit flat against the head surface. I was thinking just a piece of aluminum soda can or so, but I admit it feels a bit "bubba".

How about the choke (coil type), will it work if I block the crossover?

DO NOT use aluminum soda can ... it will burn through rather quickly. Use thin steel as we do on race cars in classes that require edelbrock 2101. First, we glue the thin steel shims directly to heads with silicone ... then we install the intake gaskets to heads. Some intake gaskets come w/ aluminum insert(s) ... they will burn through also ... do use steel.

If you block off the xover, the coil choke will not open properly.

Please note: except the lower performance aftermarket intake manifolds, all others have no xover at all. Same goes for aftermarket heads.

Unless you drive a lot when it's very cold, you could do this but you'll have to change the choke or at least wire it open. Negative: it will take a bit longer for motor to warm up to operating temp. Positives: the intake charge will run cooler (more power) and "coking" on bottom of intake will be eliminated.
JACK:gap

 

[ruby76]

It's been a while since I've rebuilt a SBC, but I believe the intake gaskets I used to get had a pre-formed exhaust cross-over metal plate to block it. I usually bought the cheap gasketsback then but Im sure the local shop will have them and would be able to show/sell em to you.