Hi Gang, working on getting the 68 project on the road,
previous owner has brand new 255-60-r15 on the car and
without thinking I got another for the spare which will
not fit. so what was the orig. size for a 68 427 / 435
conv? what size tires do you run? What is the biggest
tire that will fit in the spare tire holder? Thanks !!!

The car originally came with F-70 tires, I doubt you will get anything bigger than that in the tub. Just guessing here, but that F-70 probably was about the same as a 195-70 radial.
I'm trying to decide which tire to run on my 68 L-71. How do the 255-60's look on yours?

I have a '69 427/435 L71 convertible and as already said, stock tires are F70-15. I'm now running P215/70R-15 Cooper Lifeliner SLE Touring tires on it, including the spare. Some cars can use P225's, but some have clearance problems...it seems to be an individual thing car to car. The same goes for 60 series...it may need the fenders flared to use them. Chevy didn't start putting 60 series tires on them until about '78 and then had to flare out the wheel opening even more.

Great looking car Bruce! Looks like the 215's fill the wheel wells nicely!

Thanks for the info, I bought this car as a project, has
not been running since the early 1990's. The guy told me
the 255/60s worked well but he only drove it once for
about 10 miles before it was parked. They look great
sitting in the garage. I hope to have it on the road
by "fools" day, I will report more then. BBB

Firestone S-03’s 255/40ZR18’s (rear) were mounted on a 9” wide rim with a 4.5” backspace. The 235/45ZR17’s (Front) were mounted on an 8” wide rim with a 4.5” backspace. Don't ask me about a spare, I have other plans for that space.