I'm having problems with my exhaust and want to replace the old logs with a dry joint manifold. Did mercruiser make a dry joint for the 454-502. I think the 496's were dry joint. How the the 496 manifolds fit on the older BBC in relation to valve cover clearance?

GIL were standard manifolds on some of the older HP motors, my stock 525SC GIL had Mercriuser logos on them.

I have 496 manifolds and risers on a 454. Works fine, even with tall valve covers. You'll need new bolts (longer) and the riser exit angle / height is different. The angle & height were made up in the exhaust hose on mine (approx 14 inches of hose). If you have a close coupled riser exit it might be a problem, but can be overcome.

Ive heard the Gils had problems? I'm not too particular if they are Gil,s or stock but as long as they are a dry joint. I think Im getting water coming in between the riser and manifold because of the weight from the tail pipe that puts pressure on the riser joint.[ATTACH=CONFIG]542144[/ATTACH][ATTACH=CONFIG]542145[/ATTACH]

Nice setup!
As far as I can remember the GILs had dry joint (running e-tops now). IMCO had wet joint for sure (they look similar).

thanks BL. Im not concerned about the flow capabilities of the Gil,s vs center risers. either is going to be better than my logs and I 'll just crank up the boost. For me price is the big concern. If I can get a set of 496 manifolds for 1/2 of what Gil's cost. Ill get the 496 manifolds.

get the 496 mani's,they won't be a problem.

What about Stainless Marine? I put a set on my 525efi and so far I'm pleased.

he said he was on a budget.
Hope he's saving up to convert that carb set up to efi.That would really make those engines thrump.

That is in the works. Im going to get a EFI single plane manifold from EBAY so I can still use my intercooler. Use LS1 throttle bodies on each turbo, and controlled by a Mega Squirt system.