For the life of me I cant get my SLP 1 3/4 to seal. I've used Felpros and now I'm using hte percys dead soft (expensive as he11) gaskets and I keep seeing blowby. No matter how tight these are they still leak. I'm wondering if they are warped or something. If so , even though they are in 3 seperate pieces, can a maching shop mill it all across and make it true?

 

It may be easier to tweak the primaries by bending them a little bit. The SLP's are prone to this since there isn't a uniform flange across the primaries.

 

Been there, done that. Take them to a machine shop that has a flat-wide sander and see what they can do, that's what I did.

Take off the headers and put them flat flange down on a flat surface, like a table, and try to put some feeler guages under different spots. You could see where mine were warped, and they wouldn't even bolt up to the heads because they move/shrink a little when they cool down. Common problem.

 

Do not bend the tubes, I broke the weld between 2 tubes down inside the collector trying to bend the outer tube to get it straight and had to have it welded to fix it, get it machined flat with a belt sander or something.

 

Use high temp silicone. it is way cheaper than any gasket. A seven dollar tube will last you for years. If you have a bad warped spot, you can put the stuff on both sides of the gasket or even double up gaskets in a 'silicone sandwich'. I had to do that on the 4-6 flange and it never leaks. I haven't had to tough it all year, where I was tightning bolts and fixing gaskets all the time before.

It works mint for collector gaskets, too.