Exhaust with mini tubs, etc

'69 RR - minitubbed and springs moved inboard. Want to run the exhaust all the way to the rear and would like to see what others have do in this situation.

My old Duster had the 3.0 inch mufflers and pipes routed under the rear end housing due to having coil over shock rear suspension with ladder bars and a stock gas tank leaving no room for the exhaust to fit in there. We mounted the muffs between the rear sub frames and the outer 1/4 panels with the end of the muffs having a 45 degree short pipe on them exiting at and below the rear bumper
The muffs were a set of the older crimp style Maga flows ovals that were 14.0 inch long at around 7 to 10 inches wide with 3.0 inch side inlet with a center rear outlet
They weren't really noisy in the car at light part throttle driving but they got a lot louder at WOT above 3000 RPM
That car would pick up .002 ET and .2 MPH in the 1/8 mile by removing the complete exhaust system, it had Hooker Fenderwell headers and three inch pipes the rest of the way mounted like side pipes until they swung under the rear end housing to the muffs
That car had full aftermarket inner wheel wells all the way to the inner sub frames
Worked good, lasted a long time

I thought about running the pipes straight under the rear end but I'm not there yet. I don't think routing them over the rear will be an issue. I'm more concerned with how close they'll be to the gas tank with having to be on the inside of the frame rail.

I think this will be the way to go ...

It can be done but it requires a good fab guy. Not some monkey over at House of Exhaust. I've done a couple of cars like this and it requires a full day of cutting, bending, welding, fabricating mounts, etc.

More here

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/3017997/1.html

Maybe I'm looking at it wrong but the OP said the springs were moved inboard, which I took to mean they're mounted in the frame rail. If so that looks nice and all but it won't work unless they lose the leaf springs.

exhaust systems tend to change length as they heat up, which is why OEM's allow for it in their mounting. Bolting it solidly tot eh frame rail is probably not a good idea, unless it;s a trailer queen.

Well, I'm both the OP and the one who posted those photos and I noticed the problem right after I posted them

Modern day flex pipe similar to this - problem solved !!

What about a narrower gas tank ?
Then the tailpipes could run just inside the rails, from 90-degree insulated hangers.

Good idea ... where do I get that !!

Well, you either narrow a stock one, or call one of the EFI tank guys and tell 'em what you want.
Or a fuel cell, either in or under the trunk - see what Speedway might have.

When we added wheelie bars to my Duster - after a 300-foot ride on its rear bumper - the right side of the tank interfered.
Cut that side off (2-3 inches, IIRC) & welded flat sheet to the tank. It worked fine, never leaked a drop.
If you're doing both sides, do 1 at a time.

A tti 3" exhaust should work. I installed a whole system on a mini tubbed leaf spring relocated 68 sport Satellite

Mine is an A body Mini tube. I made my own 3 inch custom exhaust and modified my gastank(stainless).
Just some ideas for you.

^^^ That's nice - probably easier to do that with a B-body, with its tank further to the rear.

^ That's the pipe routing I was considering for mine, since I don't care about stock tips, stock tip hangers, precise stock tip locations, etc

If the stock leaf spring mounting structure is still there after the relocation, it'll make a handy place to mount exhaust hangers.

I haven't had tailpipes since the 90s....

I'm 69 years old. Time is running out. The car is getting paint now, then needs FULL reassembly. While it does need a bunch of custom fab and fitting, I'd like to keep it to a minimum. That said, I'd rather not have to modify the fuel tank. But I like what I see above. I was wondering if I could cross over through the spring and like someone said, it should be easier on the B-body. The old rear hanger structure is gone but that's not a show stopper !