After contemplating what to do with my 1965 GMC Suburban, I've come to the conclusion that what it really needs are some sidliner exhausts, ones that go down along the bottom of the car like running boards and jut out to the sides just in front of the rear wheels.

And so, the questions are as follows:

A. On a Cummins, do dual exhausts work as well as a single exhaust? What size should each exhaust be? Does anybody make headers for dual exhausts?

B. If you have dual exhausts from the headers (You know, REAL dual exhausts) what size of turbos should you have on each one? I'm thinking of some RX-7 turbos or something along those lines, but what would you guys recommend?

C. If you do have two turbos, how do you set it up so that both are providing boost to the engine? Do you need special mainfolds, or do you only have one turbo provide boost to three of the cylinders?

Thanks for any help. You have to admit that the idea of dropping a Cummins into a Suburban is better that the entire Gremlin idea...

 

The only dual exhausts on a Cummins I've seen or heard of have a Y under the bed to feed both tips.

Don't think that would work they way you want it.


phox

 

It would provide the look, but would it provide better performance to have turbos on small pipes? I think that two small turbos would spool faster and provide the same amount of boost as one large one.

I can't see how an exhaust brake could be rigged to work on duals, but it looks much cooler to have two boost gauges. That would be awesome. Then again, you'd have to buy two instead of one. It would be more expensive, probably.

 

I dont mean to shoot you down - I do like this idea a lot better - but I hope you have DEEP pockets....a conversion of this magnitude would be pretty tough and expensive, IMHO.

If you are to consider doing this, you should be posting in the 12V drivetrain section - I dont think u want to be messing around with the electronics on the third generation Cummins ISB.

Good luck.

 

Parallel turbos are not the way to go. You will lose spool up, the thing will be very boggy when you get on the gas. Plus it would be a plumber's nightmare. Just use a "Y" under the truck. 3.5" pipe from the split would be large enough.

 

So the Y is the way to go? It will be a helluva lot cheaper. (Less pipe, less gauges, less turbos.) Thanks for the help.

Now I just need the engine. I have a buddy that might give me a 2nd generation and manual tranny for a bit over 2,000, but it has over 600,000 miles on it. At that rate what would probably be included in the overhaul? Would I need new valves, pistons, or sleeving?

The funniest thing about the engine is that it's only on its second serpentine belt...

 

If it runs OK, just drop it in and drive it. A well cared for Cummins can go over a million miles.