Topic: 1969 GT500 Exhaust

[ninedrvr]

I’m in the process of building a GT500 replica. I just picked up a cast aluminum rear exhaust collector. I have two questions about this exhaust.  The first is whether the tailpipes from the muffler go directly into the collector which is what the parts manual seems to show for a GT500 or whether the pipes are necked down and then re-enlarged with an adapter? The second question is what holds the pipes or the adapters in the collector? I don’t see any provisions for a set screw. Just trying to understand how this is all supposed to work.


Jim

[Bob Gaines]

I’m in the process of building a GT500 replica. I just picked up a cast aluminum rear exhaust collector. I have two questions about this exhaust.  The first is whether the tailpipes from the muffler go directly into the collector which is what the parts manual seems to show for a GT500 or whether the pipes are necked down and then re-enlarged with an adapter? The second question is what holds the pipes or the adapters in the collector? I don’t see any provisions for a set screw. Just trying to understand how this is all supposed to work.


Jim

A genuine GT500 did not use a adapter to go into the exhaust collector. The pipe is first held by the stock Mustang exhaust tip hanger near the point of where it enters the collector. Copy the stock 69 Mustang duel exhaust and ALL of the hangers and clamps. The genuine collector had a threaded hole for a set bolt to hold the pipe firmly and drilled from the top side about a inch from the opening and another smaller approximate 1/8 drain hole drilled on the bottom side basically directly underneath the upper set bolt hole . It reads like you need to add the holes to your collector.

[ninedrvr]

What size set screw is supposed to be in the collector holding the pipes in place? Also, what length bolt and type of finish?

If I had to guess, I would say probably 5/16-18 given that the other holes are the same, and then probably P&O finish about 5/8 inch long.

[jwc66k]

Jim,
Slightly off topic: A manual to consider getting, "1969-70 Shelby Unique Parts Catalog" (available from one of the Mustang Stores that has supported this forum and posts here often) -
https://www.npdlink.com/search/products?search_terms=l-31n&top_parent=0&year=
I don't have this manual, so I can't verify it's accuracy, but I do have the 1966 Shelby book and it's pretty good. At the worst, the manual will give you something to mark up with personal observations and other pertinent input. (Example: I marked up my "66 Mustang Electrical Manual" with all the wiring harness ID tag locations.)
Jim

[ninedrvr]

I keep meaning to pick one of those up.