What's the backspace on a 1970 Firebird (front/ rear...

[Blulkie]

...wheels)? Note Camaro's and Firebird are similar but the backspace differs on these cars so I'd like to keep answers limited to 2nd gen Pontiac F-body cars only.

Most wheel places quote a backspace of 4" for the front but no one seems to know the about the rear or at least, is willing to share. I know one some cars the driveshaft can be a little off-center, resulting in slightly more backspace on one side. Please share your numbers as well as your wheel diameter & tire size, the wider the better so long as it doesn't stick out past the fender, that is not a good look.

 

[Goatman]

...wheels)? Note Camaro's and Firebird are similar but the backspace differs on these cars so I'd like to keep answers limited to 2nd gen Pontiac F-body cars only.

Most wheel places quote a backspace of 4" for the front but no one seems to know the about the rear or at least, is willing to share. I know one some cars the driveshaft can be a little off-center, resulting in slightly more backspace on one side. Please share your numbers as well as your wheel diameter & tire size, the wider the better so long as it doesn't stick out past the fender, that is not a good look.

You can fit a 10" wheel with 5" backspace on the rear but it will be at the edge of the wheelwell and you may have to do a little banging on the floor where the seatbelt mounts are and the wheel lip may need a little roll also depending on how the body is welded together the front is a different story with the turning of the wheels about 8" wide with 4-4-1/2" will be about the max ...and the tire size and aspect ratio will enter into it also ..
Again depending on how the frame is positioned in relation to the body (they shift over time)
The factory (steel) wheels for either car at the widest were 15"x7" with 4" positive offset
The widest (factory) Aluminum wheels were 8" wide with 4-1/2" positive offset..
the only way to tell for sure what will fit is to measure the wheel well from different angles and use a fitment gage to see where the Problem areas may be, what fits on one car may NOT fit another of the same model due to spring and build issues...
Good luck!