Mopar Action On-line – Tech Questions
Ryan Ruddell, Eugene, OR, 1969 Dodge Dart 340
I want my car to be similar to the “brick” (a street version). I plan to run a 5 speed and unknown gear ratio. How much tire do I need to stick 450 horsepower? I know that is a difficult question and for me it really becomes about money. To fit wider tires I see two options. First use offset spring hangers and shackles, good for about .75″. Second relocate the leaf springs over to the frame and “mini tub” it, good for about 3″. The later being substantially more expensive. So my real question is, what can I get away with? Ultimately I want to do this once so I will spend the money if needed.
Ryan, to even begin to quantify this, I’d need to know your definition of “stick”. We ran 12’s easily with stock spring / shackle locations and 225-50/15 street tires, making 500+ HP. If you are talkin’ short times in the high ones to approx. 2.0 secs, I think you’re “hooked” with no mods. If, on the other hand, you want a real launch (~1.5 sec. 60 foots), then you’ll need more tire back there. Frankly, there’s no proven formula, there’s just so many variables, chief amongst them being tire compound and air pressure.
8″ wheels will clear easily on most ’67-up A-bodies. I think the “bulged quarter panel” versions (Duster / Demon, et.al.) could probably go even wider with no mods, as long as the offset is very carfully chosen.
On the Brick, we were really more interested in fitting larger front tires!