0Willcox Corvette

Your car would have had a different set up on a 1979 with a single arm as shown below. This has to change because you'll need something to hang the intermediate pipe from at the center crossmember. The bracket posted above is available in 2 or 2.5" design depending on which kit you order and what transmission you have.

You'll need to know the tranny, and the size desired (which I'll assume 2.5") with probably an Automatic transmission.

Willcox

Priya

Thanks Ernie. Its a manual transmission and the factory exhaust was no longer on the car when I bought it, it had a true dual exhaust system on it last.

'75

I've used a couple of the complete sets from corvette central that start at 2" at the manifolds and then jump up to 2 1/2 the rest of the way back. Since they make the systems, maybe a call to them could get them to make the front pipes with 2 1/2 at the manifold and then get the rear pipes for the 73.

68notray

I have a Bendpak bender so I custom fab my own systems. BUT - why don't you buy a 2 1/2" system from one of the vendors and just cut off the smaller 6" initial head pipe and weld on a pc of 2 1/2"? If you can't do it, take it to a muffler shop.

Priya

Where can I get those two initial 6" of 2.5" pipe with the proper curve and flange?

My husband says bringing your own parts to an auto repair shop and asking them to put them on is like taking a raw steak to a restaurant and asking them to cook it for you and take the cost of the steak off the menu price.

dmruschell

As mentioned, if the car is a 4 speed, downpipes from a 65 will work and mate up to the rest of the exhaust system. I did this on my 79 and it worked perfectly.

Priya

I'll look into that if I can't get a full 2.5" system.

DUB

Priya,

Just keep this in mind.

Due to not knowing if you are going to try to use the exhaust hanger I posted a photo of.

I have run into many exhaust systems from various vendors that I have gotten that when the front down pipes were installed. They were short. They are supposed to go back far enough so the center exhaust bracket I have shown that has the area to hold the pipes is also the area that the rear pipe joins to the front pipe...and thus.. ONE muffler clamp (per pipe) is used to seal the pipes and also hold it to the center muffler bracket.

And I have had to many times...extend the portion of the center exhaust bracket to make this happen because the joint where the two pipes meet is in an area that just will not work and a modification is needed.

I am telling you this so you do not get your heart broken when you get your system in only to find out you have a problem. God knows I have many times. I now get them made to what I want. I let them know I want those front down tubes to be longer...because I can always cut off pipe.

And knowing you did not ask....just make sure that whatever you do...the very rear most exhaust hanger at the end of your muffle must be able to allow the pipe to move and flex and not be solidly/rigidly bolted to your frame. I know 'some people' think that rigidly mounting the the very end is fine. That actually makes absolutely no sense because the entire exhaust system forward of that location is allowed to move freely and independent from the frame....because the motor mounts and transmission mount are rubber insulated.

DUB

Taijutsu

I think it was Magnaflow that has a set of 2.5' dual exhaust that meets in the middle as an X pipe. It was made for a 73 w/o cats and will hopefully fit my 74? I have the 2" RHs that are too small for my 280 rwhp & 2.25" dented duals. Hopefully the 2.5 and the better duals can get me up to 300 rwhp?

R

Priya

"RHs"?

Taijutsu

Ram's Horns

Priya

I checked out the magnaflow web site. They do have a system for 68-73 350 that is 2.5" with an X pipe but don't say what size the inlet at the exhaust manifold is. Presumably 2".

Taijutsu

That would mean a 2' pipe meeting a 2.5 pipe. On extra cost alone I'm sure it is 2.5 all the way.

I'm looking forward to seeing mine on the dyno w/2.5 & proper ex.
They ran some mean SBs through the RHs. of course headers were a big improvement!

Priya

I wanted to run headers on my motor once I convert it to Tuned Port Injection but my husband said I'd better stick to factory cast iron exhaust manifolds due to the tendency of headers to leak. I'm hoping the 2.5" outlet rams horn manifolds are an improvement over the 2" outlet rams horns. I haven't heard or read anything about that.

Taijutsu

Hubby is correct, stk is less trouble. Check out these people.

https://www.castheads.com/

Priya

Interesting. When I was watching the video I thought my manifolds must be these imported ones because they look like new but they don't have the bracket mounting bosses on them and have "GM" on them and a part #3797902 on them. The ports also look more like the ported one in the video than the unported import manifold he shows. I was at first thinking maybe I could port them a bit myself but I think the outlets look thin enough now that I wouldn't want to attempt to remove any more material.