Topic: Exhaust Hole Cut Out

[kkupec02]

Even the blueprint that I bought from EBay isn't really helping me on this one. I am going to cut a 1965/66 GT exhaust trim piece on my 1/26/67 #817 built car. I had the wrong rear lower valance on it so must custom cut a standard one. Does anyone have the measurements from the rear lower tip of the panel to the outside edge of the cut and then the inside edge of the cut? Finally, the height of the cut from the bottom edge of the panel? That way, I can put my trim piece up to it and use it as a template. I also think that the cut trim piece ends just before the lower lip of the panel and does not go over it?

[jwc66k]

I am going to cut a 1965/66 GT exhaust trim piece on my 1/26/67 #817 built car.

Is this an "apples" into "oranges" situation?

Even the blueprint that I bought from EBay isn't really helping me on this one.

The "blueprint" says "OBS - 1/9/67". I read that as being "Obsolete - 1/9/67".
Jim

[Bob Gaines]

Even the blueprint that I bought from EBay isn't really helping me on this one. I am going to cut a 1965/66 GT exhaust trim piece on my 1/26/67 #817 built car. I had the wrong rear lower valance on it so must custom cut a standard one. Does anyone have the measurements from the rear lower tip of the panel to the outside edge of the cut and then the inside edge of the cut? Finally, the height of the cut from the bottom edge of the panel? That way, I can put my trim piece up to it and use it as a template. I also think that the cut trim piece ends just before the lower lip of the panel and does not go over it?

I think what you bought has to do with the little used flat ,cast aluminum piece .It was used on some early Shelby's and Cougars. The illustration does not appear to be of the 65/66 sheet metal exhaust trim piece.   

[kkupec02]

Does anyone have the specs for the 1965/66 GT cut?

[jwc66k]

Does anyone have the specs for the 1965/66 GT cut?

If you are attempting to use 65-66 Dual Exhaust rings on a 67, the 65-66 documentation will not be useful, the centerlines of the exhaust systems are different between the two body styles and the exhaust tip locations are different.
If you want to use 65-66 Dual Exhaust rings: mark the spot on the rear valence where both exhaust tips will be located; measure the position of the mark from the center out, the ends in, and the up/down location; remove the valence; mask the area with tape (for the next step and to reduce paint damage); center a ring over the mark; draw an approximate outline of the hole using the INSIDE of the ring (your actual hole will be larger - don't forget the alignment holes for the retainer tabs); cut.
Remember that the 65-66 installation had internal adjustments on the frame for the exhaust hangers to compensate for "minor" differences. A 67 does not have these.
Jim

[kkupec02]

Thanks. I actually started that process this afternoon when I found no good templates to use from other cars. I found that the GT valance that I had was centered really well with the exhaust tips. The exhaust tips were really consistent at 1 1/2" spaced from left to right at each hole on the GT valance, ie 1 1/2" space on each side of each exhaust tip. The tips were also consistent at 1/2 from the top of the exhaust tip to the top of the GT valance cut. Using that valance as a template, I then penciled in where the GT cuts were and where the exhaust tips were to be on the new bare metal standard panel that I am prepping. Tomorrow I am going to figure out where I should cut the GT trim piece for maximum opening to give the exhaust tips room to flex on bumps. I am thinking that I measure the widest spot on the trim ring and cut it there for maximum opening at the bottom of the valance, but haven't gotten there yet. I also believe that the trim ring goes to the rear valance lip but not over it.

[J_Speegle]

As a side comment think it might be interesting and helpful if we try and figure out when the change over was from at least the main two groups of how the rear valance was either trimmed and dressed and those that were not - with the factory Mustang style cut outs.

Will take some time and put something together in another thread and reference this thread in it to keep things neat and tidy

[Bob Gaines]

The pictures are of the two styles used to trim the hand cut exhaust opening in the rear valance. The modified 65/66 Mustang GT exhaust trim is by far the most typical of the two. The second style is a cast aluminum part also used on some Cougars. It is the least common seen .  The first style (GT modified)was used to begin with in production and also when the hand cut rear valance was phased out later . The cast style was used sporadically in between from my observations.

[Texas Swede]

When I bought #1317 in L.A. area 1977 it had cut outs in the rear valence with 3 holes drilled, one on each side and one at the top.
The trim rings were missing. After some time, I found out that Shelby used the 65/66 GT exhaust trim. Bought a pair and checked where to cut them. The 3 bolts were soldered in the back, and they fitted perfectly in the holes. Cut the trims and put them on. Later, I found out that the top bolt was going through a drilled hole at the top of the trim. Looked like I had used the wrong half of the cut trim. Never changed it as they fitted
perfectly on my car.
Texas Swede

[Bob Gaines]

When I bought #1317 in L.A. area 1977 it had cut outs in the rear valence with 3 holes drilled, one on each side and one at the top.
The trim rings were missing. After some time, I found out that Shelby used the 65/66 GT exhaust trim. Bought a pair and checked where to cut them. The 3 bolts were soldered in the back, and they fitted perfectly in the holes. Cut the trims and put them on. Later, I found out that the top bolt was going through a drilled hole at the top of the trim. Looked like I had used the wrong half of the cut trim. Never changed it as they fitted
perfectly on my car.
Texas Swede

The earliest 65/66 modified trim rings had a hole drilled through the trim and a slotted stove bolt head machine screw was used in the top. Not all of the rings used had a top hole filled with a bolt fastener .

[kkupec02]

Thanks for the pictures Bob. Even that is a help where there doesn't seem to be much information. I can now see where to cut the trim ring. Then I can use it as a template for the hole in the standard valance.