[EricVonHa]

Me? Replacing exhaust manifold gaskets on the 77 Deville. The center manifold bolts have locking tabs to keep the bolts secure. The outermost 2 bolts at the front and rear of the head? No locks on those. The rearmost bolt on the driver said was loosening itself over many years and eventually deteriorated the gasket. Tried tightening up the bolt and it did not quiet down the exhaust leak. So, in goes new gaskets!

 

[drmenard]

There are some places that carry copper gaskets for the 500, 472 and 425 motors. I only use grade 8 bolts on exhaust manifolds.

 

[LV_Cady]

Thankfully GM did away with the locking exhaust manifold bolts by the mid 90's.

Depending on the gasket or if you notch the outter holes you don't need to completely remove to slam a gasket.
But slipping in a gasket is taking a chance if it not working.

Many of the older GM's never used exhaust manifold gaskets from the factory.
the gasket was more of a fix for a warped manifold.

The best fix would be to have the manifold machined flat and install like the factory.
With new quality grade 5 or 8 bolts & split lock washers.

Then you may have to deal with the studs to the pipe & sometimes a doughnut gasket if completely removed.
Which could be easy or a PITA depending on the condition.

Don't use generic hardware store stainless steel.
The stainless is not as strong & can break.

 

[EricVonHa]

Yeap, picked up some Grade 8 bolts. Interestingly enuff, the OEM bolts are like 1 1/16".

I got 1 1/4" and they barely and I mean barely kiss the head bolts without the OEM bolt locks. Using the locks, no problem.

Exhaust is quiet again. Thankfully.