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Thread: Intake Manifold Crossover Question

  1. #1
    El Prosecutor
    I just bought a used Performer intake for my Olds from Tom at JBP.
    I also have a new set of Felpro gaskets like this:
    http://static.summitracing.com/globa...fpp-1356_w.jpg
    Notice there are no holes for the exhaust crossovers. I was going to buy the plugs to block the crossover in the intake but was wondering if this kind of gasket alone would be sufficient to block the crossover, or would it burn through?

  2. #2
    Jetaholic
    I just bought a used Performer intake for my Olds from Tom at JBP.
    I also have a new set of Felpro gaskets like this:
    http://static.summitracing.com/globa...fpp-1356_w.jpg
    Notice there are no holes for the exhaust crossovers. I was going to buy the plugs to block the crossover in the intake but was wondering if this kind of gasket alone would be sufficient to block the crossover, or would it burn through?
    I know on a Chevy that type of gasket is sufficient, but on an Olds I'm not sure. I've been told that the crossovers on Olds heads need to be blocked off. I remember when I bought a Performer intake for an Olds it came with a couple of iron plugs that you grind to fit the crossover holes. The problem seemed to be that the manifold would warp in that area due to the high exhaust temps on an Olds. This problem apparently doesn't exist on a Chevy (at least not that I've heard of anyway) but on the Olds it apparently does. Personally I don't see how it could be a problem on one engine, and not on another.

  3. #3
    malcolm
    Yeah, they will burn through.

  4. #4
    Senior Member
    Join Date
    Dec 2009
    Posts
    648
    I've blocked em off before with a piece of stainless sheet metal. Your not going to use those end rubber gaskets are you?

  5. #5
    Steve the small fabricated plates like I described are OK ,make sure they are thinner than the "crushed gasket" thickness) the other way is to get the Edelbrock iron plugs (pain in the A$$ to grind and fit) BTW this is worth the effort Tom
    btw. I've seen guys melt aluminum (piston material) into the cross/port and grind (not an option here,cause the heads aren't off) any how I recently saw one of these done that way that had a chunk of said material get loose and fall into the combustion process not a pretty sight

  6. #6
    El Prosecutor
    Steve the small fabricated plates like I described are OK ,make sure they are thinner than the "crushed gasket" thickness) the other way is to get the Edelbrock iron plugs (pain in the A$$ to grind and fit) BTW this is worth the effort Tom
    btw. I've seen guys melt aluminum (piston material) into the cross/port and grind (not an option here,cause the heads aren't off) any how I recently saw one of these done that way that had a chunk of said material get loose and fall into the combustion process not a pretty sight
    Thanks Tom, I have some stainless I could make plates out of. Would I put them on the Head side or the intake side of the gasket? Attach with formagasket or what?

  7. #7
    Steve make them slightly larger than the actual ports then trace them onto the gasket and cut out the gasket material in the same area Thus making an insert into the actual gasket Tom

  8. #8
    El Prosecutor
    Thanks Tom will do. H2OMofo - I am going to ditch the end rubbers and use a fat bead of silicone. I think we are on the same page on that? I have read that the rubber end gaskets leak.

  9. #9
    Steve with all due respect "silicone blows" use GMS or "Right stuff" ,its "vulcanizes" like rubber (Kragens) Right-stuffs the best thing since beer in cans !! Tom
    BTW heres a "tip' take a pointed punch and hammer and "peen" the block and manifold seal surfaces (ends) it will help hold the sealant in place (especially important on OLDS)

  10. #10
    Boostedballs
    I assume your heads are still on the engine...I would just have the intake welded shut and call it good. My performer cracked in the crossover so I ground a step around the crossover ports and dropped in some 1/4" aluminum plate and tig welded it.
    If the heads are off, I would fill the heat riser passages in the heads with aluminum and then clean up the bowls. Also, grind off the nasty A.I.R. bumps in the exhaust ports. Olds flow like crap on the hot side.

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