Installing dual exhausts on a 1979 Zephyr

[Eastyorkstang]

Swapping the 3.3 -6/C4 for a 302/aod and 8.8

What needs to be done to go from a single exhaust to duals ?

What needs to be done to install the 8.8 ?

Thanks in advance

Darryl

[richpet]

You will need the 'double hump' cross member so two pipes can run under the car.

Then you need to decide on the exhaust/cat back.
The non true dual cars ran a brake line on top of the rear axle. So if you're using tailpipes you will need to run the brake lines from the 8.8 to avoid brake line/pipe interference. If you're going to use dumps (like I did) then that does not matter since the exhaust pipe never gets to the rear axle.
The 8.8 bolts right in, uses the same control arms and such as the 7.5. Yes, some were round bushings and some were oval. Doesn't matter - they fit.
If the 8.8 is from a 94/95 model they had rear disc brakes and longer axles. That can affect rear wheel offset, or use fox length axles.
Your cheapo option? 8.8, swap all the old brake lines on to it and run factory drums. Don't forget the axle vent as the 8.8 cars run the brake line there so the vents are different styles, but interchange.
At the time I did mine I didn't want to mess with prop valves, etc., so my 8.8 got 4-lug axles (94/95 are also 5-kug) as I already had a set of 4-lug wheels I planned to use. All the brake lines from my '81 7.5 got swapped on and I am running drums. I did have to make one brake line, but I think that's because I had a bad one?

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[gmatt]

re: the rear brake lines. If you use the 8.8 dual exhaust axle lines that have the flexible line in the middle, you'll need the fitting/bracket that mounts to the chassis in front of the pumpkin. LMR sells this bracket and it uses existing holes in the chassis to mount. From there you'll need to make a hard line to connect to your chassis hard line (where the soft line connected from your 7.5) Or you can get a pre-bent Mustang dual exhaust hard line that runs from the firewall all the way back to the bracket. I've done it both ways. The Mustang line has enough bends in it that you can make it reach by slightly straightening.

Or, as stated, you can transfer the 7.5 axle lines to the 8.8, which requires a little re-shaping, but it works.

[Bentley]

I got the 7.5 inch lines to fit the 9" going in my 83.. Unfortunately I did not know that I had to change it to accommodate dual exhausts, so I will have to redo all of this....