jlpskydive

Sooo I'm converting my 78 from the 2-1-2 to a true dual set up. I bought the kit from Corvette America and it looks nice, but for the life of me I can NOT figure out how to install the center hanger bracket. I got the old single sided one out without a problem. But this part of the puzzle is really frustrating me. This is the part I'm talking about. http://www.corvetteamerica.com/cf/part.cfm?partno=36627

Thanks.

Alan 71

Hi j,
I'believe you'll find the bracket typically bolts to the rear of the transmission.
Regards,
Alan

From the 71 AIM M40 sheets. Items # 8, 9, 10, and 11.

jlpskydive

Alan, as always you are the best. How high can I jack the trans up without breaking anything?? is this something that can do with out breaking the engine or anything else loose?? Hopefully....

Paul Drennan

This could be a problem for a 78 with automatic. I think that car would have a 350TH instead of a 400TH. A bigger problem would be that NO post 76 or 77 cars with the 350TH ever came with "true dual" exhaust. Even if the bolt spacing was the same on the 350TH, the length of the trans would be different and therefore not match the joint on the pipes. I'm sure something could be fabricated though.

jlpskydive

Welp I just checked and there is no way that bracket is bolting to the back of the trans.... DAM IT... I pulled the Trans mount off and it was easy enough four bolts and off. Floor jack raised it up about an inch and I had a pretty clear picture of the the spot that Alan's diagram shows and it's not the same on mine. I think I will just put it together and take it to a muffler shop and have them fab something for me. ANYONE done a true dual on a 78 auto please chime in if I'm wrong, but I'm at my wits end on this one. It's a STUPID exhaust... It should not be this hard. I know I'm missing something or they sent me the wrong/there is no, part.

KapsSA

That bracket won't work with the 350 trans.
I believe years ago Mid America used to have a home made bracket that was half manual trans bracket and half auto bracket welded together for use with later auto Vettes.

KapsSA

Here.........
http://www.mamotorworks.com/Corvette...acket-618957-1

Alan 71

Hi KSA,
Nicely done!!!!
Regards,
Alan

KapsSA

I might ad years ago I removed the dual exhaust from my manual trans 79 and installed it on a friends auto 78.
We didn't even use a hanger at the crossmember, everything was tight and stayed in place.
The difference between auto and manual dual exhaust is that the manual pipes go straight through the crossmember holes while one side of the auto pipes goes through at an angle to clear the trans.
I've wondered if a manual trans hanger with the curved sections that cradle the pipes could work if the curved section on the angled side was cut down to just a "tab", enough to just get a clamp around it and the pipe and a relief opening made as on the "homemade" hanger.
http://www.mamotorworks.com/Corvette...er-gm-603652-1

Alan 71

Hi KSA,
Here's the 4-speed hanger bracket in place.
???
Regards,
Alan




The front pipes in place.

mark79,80

I purchased this bracket to use with a Corvette Central dual exhaust kit for my recently sold 1979. It fit perfectly. Problem I encountered after installing it, is that the pipes were a bit too low to fit thru the crossmember holes.

To solve this, I purchased a high performance rear transmission mount from my local Advance Auto store. This raised up the center exhaust hanger so that the pipes were centered in the crossmember holes.

KapsSA

I'm wondering if the one side curved part that cradles the pipe could be cut back leaving just like a 1/2" wide tab so the angled pass side pipe could be clamped up to it.
The pic of the Mid America hanger also shows a cutout for something on the auto trans not on the manual trans.

jlpskydive

Thanks man the other bracket was driving me CRAZY!! That's what thought should look like out of the gate!!

jlpskydive

Is the one you bought?

https://shop.advanceautoparts.com/p/...lVehicle=false

mark79,80

It looks like the same part. You might not need it, if the pipes can pass thru the crossmember holes after the new center exhaust hanger is installed.