I would not run a wheel taller than 17" on one of these cars.  Keep in mind they had 15" wheels stock, and a lot more sidewall.  The sidewall was in effect a part of the suspension, helping to soak up bumps.  Going to stiffer springs, etc. to improve handling was pretty much not noticeable (so long as you kept it within reason) with stock wheels and tires because you had that sidewall.  When you remove a lot of that sidewall you lose that, and now the car may feel harsh, or stiff.

I went to 17s from stock wheels.  I have typical suspension upgrades (620 font coils, poly bushings, bigger sway bar, Shelby/Arning drop).  Its definitely a stiffer ride than before.  Mostly its not objectionable, but its right on the edge of where I think it would start to become objectionable if I'd gone to a bigger wheel.  I have a 40 series tire on the front because a 45 series hit the fenders.  Going to an 18" wheel you are going to have to go to a 35 or 30 series tire to allow the tire to physically fit inside the wheel wells.  That's very little sidewall.

17s will clear 13" diameter brakes, maybe larger, so there's no benefit on that front to an 18" wheel.

As far as the offset goes, modern wheels use a totally different concept when it comes to offset.  Basically they push the mounting pad as far outward as possible.  '60s and '70's era cars had the mounting pad a lot closer to centered.  Consequently I imagine a spacer is going to be required.  I can't say on thickness specifically, but I would guess you'd be lucky to get away with only a 1 spacer.

My advice would be stick to wheels 17" and under.  Cheap parts that force compromises are not worth it.  You end up spending more money and time trying to get them to work to your satisfaction than it would have cost to just buy something that fit right to start.

You need to find out what offset or backspace they are. A 1" spacer may be fine, or it may not, as the later 18's came in a few different offsets I think.

I have 18x8.5's on the front with a 235/40 tire and a 0 offset, and 20x8.5's on the rear with 235/30's and a +10 offset. This is on a 65 and required good rolling of the fender lips. You have much more space in your wheel wells so I don't see a bigger profile being an issue. Ride is a bit harsh but I have bearing control arms and strud rods, strong lowered springs etc, so I didn't notice anything when I swapped to bigger wheels over the 17's.

On the 17's I had, I ran a 234/45 series semi slick tire that runs a little large, and that fit both front and rear with an 8" 4.75 backpsace wheel. Fender lip rolling was required on the rear.

 

Last edited by Husky65 (11/18/2018 2:45 PM)

Probably 1.5" spacer required.  They do make wheels now that actually fit.  That would be my choice.

wow!

I like it.....thanks for sharing the pics....

Nasty!!! I like it!

Too far? Where do you live Husky? I'm a mere 2,275 miles away and will be there.

Husky65 wrote:

Around 9,500 miles away ha ha. I'm in Sydney Australia.

Thought you were a bit far away after i noted the license plate on one car in your pic........maybe you could host the bash and we'll make the trip!

As I've already mentioned, your car is one of my favourites in Oz.
Post some more pics so the guys here can see how we do it down under.
Seriously consider getting yourself to a Bash .... the most fun you can have standing up.