I like to run M/T ET slicks on my car. Last year I ran 29.5 x 10.5S on 8" rims which narrowed the section width from the advertized 13.2 inches to right @ 12". I'm thinking of ordering a new set of Welds which are 10" wide as recommended, w/ 5.5" backspacing but I'm worried that the added width will grow the section width to the advertised 13.2 " and then they won't fit.
My other option is to run 28 x 10.5S tires on my 8" rim. I can afford the higher RPM without any problem.
So my 2 questions are;

What do you think would perform better;
The bigger tires on the 8" rims?
or
the 28" tires on the 8" rims?

and do you think I can get the 29.5 x 10.5's on 10" rims w/ 5.5" BS under my car.
The car is a 67 w/ 67 rear end and I've ground the lips as much as possible.
Thanks for any and all input.

My experience is that the overall width runs a little wider than advertised. For instance, I mounted 28 x 10.5 MT slicks on a 10" wheel. Advertised width is 11.7 but I measured 12.875. I also have 295/65 MT Drag Radials mounted on a 10" wheel, advertised is 12.4", but I measured it at 12.875 again. I'm not sure how they measure them but I pump them up to max recommended pressure, lay them on the floor with a straight edge across the top and measure.

Have you considered notching the rear frame rails? I took 1-1/2" out of the rails on my 65 Camino, leaving the inside rail wall intact, then boxed it back in. The 10" wheels have a 6-1/2" backspace and with just a little clearancing on the outer wells, will have fair clearance for the above mentioned tires.

Regards/ Dave

Will tubes help to reduce the section width a little?

Joe