'68 Shelby GT 500 questions

Frank,

Everybody with a '67 or '68 Shelby has this problem to one one degree or another. I think '67s are a bit worse than the '68s because the fiberglass parts don't fit as well as those on a '68. The problem is that the rear deck spoiler creates a low pressure area at the back of the car and exaust fumes get pulled into passenger compartment when the window are lowerer because the window opening acts as an exit. The best you can do is make sure that every opening no matter how small is sealed in the back. That should help some, but I think you'll always have some fumes in the passenger compartment no matter what. Maybe some others here can provide alternate answers (and I sure they will). Hope this helps.

 

My Grandad showed me this one- Slam a dollar in the lid seal and slide it out. If there is resistance, that spot is OK. Work your way around, and if it slides out easily, you have found your air leak. Then, of course, there are dozens of plugs, foam gaskets, gas tank sealer, etc., to look at.

 

Well, I've owned my 68 F.B.P.I.for some 14 years now, & I some how don't seemed to have that problem. Don't know if thats good or bad ? I only drive it in the summer months & the windows are always down. Just to local cruise nights, about 500 miles a year.---S.

 

If all you needed to eliminate the problem was a new decklid seal, I'd be out in the garage with a scraper tomorrow morning.

 

Seaweed,

The problem is unique to '67 and '68 Shelbys (don't know about '69s) because of the spoiler. Regular fastbacks don't seem to have the problem.

 

Yes, the 67's have more of a problem than the 68's, but, here goes:

1) Look along the rear panel on the inside for any hole. Wire rubber seal not fitted all the way in, bolt missing, gap in the deck lid seal, loose weatherstrip, missing fender drip seal (1/4 panel)
2) make sure the tail light seal to the body
3) make sure the tail pipe tips stick out past the end of the pan

4) and sometimes the gas pedal and/or the clutch linkage seals on the firewall are bad (worn/torn) check those too.

 

I have a 67 not a 68 ,but if the fit is the same try california car cover company for a car cover....they arent cheap(i think mine was about 250)but they are custom fitted to the shelbys dimension and fit like a glove....hope this helps..Trent

 

Today I took the tail lights and rear panel off of my 67 for an upgrade. One area that probably gets overlooked is where the four studs on each side of the tail lights seal to the body. Well, the studs seal but the way the mounting block for the studs is designed, I can see how fumes can leak in around them. This area must also be sealed.
I'm not sure if the 68 panel fits to the car the same way as the 68's do.

 

Indoor only or indoor/outdoor?

The indoor/outdoor need to breathe and will let really fine dust through. The indoor only are dustproof. For my 68 Mustang vert I bought a special extra thick "indoor only" custom fitted cover from NPD. Made by Durafin. Probably weighs 25 pounds but boy is it thick and it has a very soft flannel liner.

IMO any of the "custom fit" covers for a 67/68 fastback will work just fine. Unless you park outside with really high winds.

 

I have to disagree. I did just that many moons ago and to tell ya it fits yes, but the 67/68 Shelby's are longer in the nose and the rear spoiler that adds length to the cover. I wish I bought a cover made for the Shelby's and not just for the 67/68 Fastback Mustangs.

Anyway, that's my input.