I am not going to be able to replicate the original muffler and tail pipe, and would rather use something a little more advanced. But I would like to at least make the tail pipes look similar to the original pieces.

Does anyone know if these were originally polished or chromed? Straight or slant cut? Rolled tip, rolled in or rolled out? Diameter and spacing between the two pipes?

I would think they were around 40mm diameter...

I think I will end up with 2 1/4 inch (57mm) from the collector to the rear muffler, and 2 inch (51mm) twin tips. I can't find much that is 2 inch inlet with a straight through style.

It looks like someone modified and plumbed in a resonator under the rear seat. A big rectangular looking thing with a lot of really tight right angle bends and a lot of thick rust. It definitely does not look original. I may have to get creative with this piece, I wanted to use a resonator or more mufflers under the car anyway. I want an aggressive tone and good flow, but not deafness.

Appearance from the rear twins to the rear, I will attach a photo of the rear of my car which has been replicated to as near as possible to the original set up in stainless steel.

I hope this assists you the exhaust is single from the extractors, to the front of the muffler in front of the rear axle where the muffler is located, from there the two pipes come out at the rear, I hope this is what you are after?

Good picture.

I will have to measure the height of the tailgate name garnish, but it looks like 1 7/8 - 2 1/4 inch tips, with the space between about 75% of the diameter of the tips. That's really close together.

The tips also look like pencil tip with the ends rolled in to exaggerate the circle.

I don't think they are as large as 21/4 inch tips, I will measure later and post again, the originals on new cars were not large however just passed our noise laws when new, that was one of the early comments made on the GT they were supposed to be noisy.
I will get back to you.

Hi There JT191,
THE MEASUREMENTS OF THE PIPES ON MY CAR ARE; OUTER DIAMETER OF THE TIPS IS 47MM, THE SPACE BETWEEN THE PIPES IS 26 MM.
I hope this helps you??
DM.

Hi DaveM,

Do you have a pic of the rear exhaust mount from underneath on the GT?
I'm hoping to make up something similar for the Bell.
Also ... do you know what the rear muffler came off that you used to replicate the GT look.

Cheers
Rob

i do believe these are the proper pipes as going on by original panflet 68 gt are 50 mmm slite angle from muffler ?

Hi JT, sorry I'm so slow to get to this, hope it's some help.
My parts donor is fitted with an original equipment system (aibeit rusty). When I get to taking it off to copy, I could take more pics.

Original muffler with heat shield.



Outlets - 32mm / 1 1/2 inch Dia. (inside)



Twin pipes from side outlet of muffler (single pipe from headers to side inlet if muffler)



Detail of rear support - shaped bracket, rubber block mounted.



Cheers, Matt.

Is it possible that there are two different versions of the GT exhaust? The pictures I have seen show a muffler behind the rear bumper and a resonator under the rear seat. Your picture titled muffler looks like the resonator under the rear seat.

But the tail pipe arrangement picture provides some good details that I can use to double check. The pipes are actually 25% closer together than the pipe width. I will have to reproduce that angle cut with stainless pipe.

the "earlier" style is what farmer has posted, and is the most common GT pipe layout, with a single muffler under the backseat and straight thru pipes out. the "later" style had a resonator under the seat and a muffler under the boot (trunk for our u.s. cousins) floor.
it seems that this change happened around the time of the release of the GT-R in mid 69, and would explain why 68 1/2 GT's like Dave's have the earlier style and Rod's have the later style, even though they are both the same later version PR91's.

hope this helps.