67 Firebird question

[Big Eddie]

I currently have 18 x 8" (4.5" bs.) with 245-40-18" tires on the rear of my 67 Bird. I measured & have approximately 2.5" clearance to the inside of the fenderwell & about 1/2" clearance to outside (non rolled lip). My question is this, if I widened my rear wheel to a 9" wheel (the bs should now be 5.5"?) would that still give me the clearance I need to run a 275-40-18? Plus I'd be willing to roll fender lip & do some hammering to inside if needed.

Thanks for any & all help!

[dhutton]

That sounds about right to me. The Camaro guys run a 5.5 inch backspace with a 9.5 inch wheel but I think the Pontiac rear end is a little wider, hence the slightly larger backspace. Any good wheel vendor should be able to help you. At the very least make sure you get a few more opinions.

[454ragtop]

The way I figure it, with the change, basically adding 1 inch to the inside only of your current wheels, you'll have 1.5" clearance to the inside and 1/2" clearance to the outside. Seems like you'd be better off with a 6" BS wheel, giving you 1" clearance both inside and outside, no?
HTH, Jim

[Torquedork]

You should also consider the ride height of your car and compare the section widths of both the tire you have now and the tire size you want to run.

[Big Eddie]

Thanks for the replys guys. My car will be lowered approximately 3" in the front & about 1.5-2" in the rear. (ridetech front coilover set up & hotchkis rear springs)
As far as the tires...looking at the Nitto NT555's that have a od. of 26.61 & section width of 11.06" according to their website vs. what I have now of 25.7" od & 9.8" section width. So looking like 6" bs. is what works on a 9" for the Firebird guys & 5.5" for the Camaro guys.

Thanks again!