Currently have a 73 LS4 with aluminum rims sporting normal 225 70 15's. Just refreshed a set of AZ stamped 73 rallies (8 inch). Is there way to look at the rim and see whether they are ET-1 or ET-3...as those were the two factory offset sizes for that year? Is it stamped somewhere on the rim? I would like to go with the more aggressive 255 60 15's that were put out on the ET-3 rallies that year. Since the difference in the offset of both factory issued rims is only 2 mils, does it matter? Do want any ugliness when turning.

Thanks in advance.

 

All AZ stamped wheels (15" X 8") should have 4" of backspacing, which means zero offset. I've never see an AZ wheel with anything different.

I also have run 255/60-15" all the way around on my '73. I'm using the YJ8 alloy wheels which are also 15" X 8" with zero offset and have had no issues beyond some minor rubbing on the drivers side front wheel-well. My LF tire rubs the head of a carriage bolt that goes through the frame at full left turn lock only. It keeps the head of the bolt nice and shiny....

You can measure the offset for yourself using this method if you have doubts...
Good luck... Gusto

 

I appreciate the assist. I thought I had what appeared to be correct info from a reliable source online...it would appear not. Going with the 255's this week, fingers crossed. Thanks again.