I have the same problem, hesitant to commit the cash for four wheels that might not be right. So far I have tried to use the advise of the guys at Bebops in Tennessee where I ordered a lot of my chassis parts (really TCI parts). They recommend a backspace of 3 3/4" for a Maverick 8" rear with the Model-A wheel well on the rear with a 7x15 rear wheel. Then they advise a 14x6 front wheel without any mention of backspace. I have measured using the site:

http://www.earlywheel.com/choosing.html

and an 8" piece of wood on each side plus the 56 1/2" drum-to-drum width and I get 65" with 3 3/4" backspace, but measuring on a real steel '29 sport coupe I only get 66" maximum width inside the fenders. That is a bit close for me so I repeat it here in the hope that some other person with a full fendered '29 Ford can comment on the 66" width? BUT (!!) now you have me worried about the front wheels! I have an Econo Kit with midsize GM caliphers and Dodge rotors, so I have no idea what offset will clear the front disk brakes. Sadly my mind was frozen back when 6.70x15 and 7.10x15 were widely available wheels and tires but now it is a real free-for-all in tire/wheel sizes. Can you give me a hint at how to estimate the offset for the front wheels? The guys at Bebops are busy building a lot of '32s and very few '29s so I am not sure they are telling me right for the '29. Personally I would rather have 15x7 on the rear and 15x6 on the front, not 14x6 on the front. I am guessing that the 15x6 fronts would have a better chance of clearing the front rotors. I can't see any way short of cutting up a wheel as Streets suggests to estimate the offset for the fronts, but I have no way to cut a rim in that way. Maybe there is someone out there who has done this before for a '29 Model-A with a Maverick rear?

Don Shillady
Retired Scientist/teen rodder