[JUDGE3]

what size dynomax super turbos are folks tucking under the 70-81 firebird?

[HWYSTR455]

I think 16" is what I have run in the past, but you MIGHT be able to get 18" in there. I don't think so, but you might.

If you run an H instead of a Y pipe, 18" would be more likely. Y pipe and you will most likely be forced to run a 14", MAYBE a 16".

The constraint is the distance from the crossmember to the differential tunnel and tailpipe. If you hang a tailpipe over the rear and put a muffler on there, you will see what I'm trying to get at. (Even if I'm not explaining it well).

This is taking the use of 2.5" pipes, with 3", because of the bends, it will def only be 14", and it will obviously be closer to the ground, too. And it would most likely have to be a 70-74 car.

Later years, like @ '75-up, also have floor pan differences due to the use of cats.

It's been a while since I've been down this road, but that's how I remember it. Hopefully others will chime in, and with more recent experiences.



.

[SD455DJ]

I have 14" Turbo-style MagnaFlows in a 2.5" mandrel bent X-pipe system on my '70 Formula 400. It's a fairly quite exhaust and not too rowdy at full throttle, probably due to the X-pipe. The car came with this exhaust and is fairly new, so I'm keeping it to save money for other improvements. I haven't had any collisions with speed bumps yet and it tucks up pretty well considering, mufflers and all. I believe the 78-79 W72's F-bodies had under-the-floor resonators that looked similar to 14" turbo mufflers, so they will 'fit'.

Dennis

[tooski]

17733 for the 68 and 17734 for the 75. Either will fit under both cars.