Exhaust Recommendations 65 GMC 4x4 305e

[vanhow10]

I'm looking for recommendations on what to do with my leaky exhaust. For the time being I am going to run the original 305e V-6.

I think I would like to increase the diameter of the exhaust pipes and a run a dual exhaust.

Do I need to have some kind of cross over? or can the exhaust have two separate runs to the back of the truck?

[Rich 5150 69]

I would keep the tube size down to 2 inch if your changing to duals with either a x or h pipe, run all the way to the back, this will help keep the low end power.

[FetchMeAPepsi]

Hey Vanhow10! Mines same as yours except for the year, 62.

For the big block 305v6 the guys at the GMC club (6066gmcclub.com) say first, make sure you dont interfere with shock travel when you run your pipes. it happens all the time.

Then go with a dual exhaust with a crossover pipe You can put Orange RTV Silicone around the ports before installing the header gaskets and they won't leak. Pipes should be 2 1/2 inch in diameter. That's a great engine you got in there buddy. enjoy it's originality!


As for low power, it will tow a house and four condos behind it at idle with both exhausts plugged with concrete. Even more if you put some throttle to it

[Snailed]

You can absolutely run a divorced exhaust with no X or H pipes if you want to.

[MusicMan70]

I have 2 1/2" and an X-pipe all the way back with Hooker Aerochambers and yes; you may also run it without the X or H mod as Snailed suggested.

[FetchMeAPepsi]

Originally Posted by Snailed

You can absolutely run a divorced exhaust with no X or H pipes if you want to.

You can run a dual exhaust with butter flavor and put popcorn in it if you want to, but for best performance you'll want to have a crossover pipe. These balance the back pressure and increase performance.


I guess it all depends on what you're looking to do. If you just want two pipes out the back and don't really want to put the time into it then go straight pipes. it'll be cheaper by a little.

[vanhow10]

Thanks for the insights. I was wondering why the cross-over was important.