I have a 69 bird with a rebuilt 455 that is putting out about mid 400s HP. I am in the middle of putting in a T-56 six speed. I have been running the stock 14 in wheels and clearly cannot hook up that kind of horsepower. I am planning to go with 17 in Rally II wheels but am debating between the the 17 x 7s versus putting a pair of 17 x 9s on the back and some 17 x 8s on the front. YearOne sells 4-wheel sets of these so it must be a fairly common choice. My question is...how different is the handling between these two setups? I am not looking to create a pro-touring type of handling nor a pure strait line dragster, but I would like it to hook up the power reasonably well and also handle well enough for daily driving on the in-town streets and down the Interstate. I don't want to create something that is not fun to drive. I would appreciate any insights on how well my bird would handle with the wider wheels/tires versus the those on the 17 x 7s.
Mark, Owner of 1969 Firebird coup with 455 added from 73 Grand Prix
I just put a staggered set of Year One Rally II's on my 68 vert. Spent some time talking to them about front tire rub. They assured me of the correct size. They even used the same size on a LS6 swap that was lowered 3" and caused them no problems. I ordered by their recommendation, and guess what....they rub. I changed out my inner fender bolts but they still rub. It is frustrating, and I am still looking at options. It is good to have discussion here so we might save others from this issue once it is sorted.
As far as handling....I love the way it responds now MUCH better than the original 14" rally's. No comparison in my opinion.
17x8's with 235/45/17 on front. 17x9's with 275/40/17 on rear.
1968 Firebird 400 Convetible 1977 Firebird Formula
They are made by US Mags. I went with the 17x8 in front which I believe is a 4.5" backspacing and 17x9 in the rear which I believe is a 5.5" backspace. I went with Nitto NT555 G2 tires that are 235/45/17 in front and 255/50/17 in the rear.
Dave there confirmed that 235 would fit on the front but wasn't sure what the widest rear would (due to the 69 only fenders) be so I went with a 255 to be on the safe side for now. I had 245 tires all around on the factory 14" (x7" ???) Rally II wheel but I don't know what backspacing those were.
I've only test fit them on the car as of yet and haven't done any driving. I'm replacing my rear end and going to Hotchkis tubular a-arms so I sure hope I don't have running issues in front. I am also running the Hotchkis 2" drop front springs and am installing Global West solid sub-frame bushings that also drop 1/2". In the rear I'm installing the Hotchkis leaf springs that are a 2" drop but I'll probably have to install adjustable shackles because I want the rear to be higher than the front.
Last edited by anguilla1980; 06/19/1905:15 PM.
http://www.TheFOAT.com/92GTA 1969 Pontiac Firebird w/BP 461ci stroker kit, 670 heads & XE274H cam. Primer black w/black interior. 1992 Pontiac Trans Am GTA w/SLP Performance Package. Dark Jade Grey Metallic, grey leather, T-Tops.