I currently have B.F. Goodrich 235/60/14's on my 1972 442. My motor (fresh rebuild) Tacs 3000rpm @ 60mph. Car has 342 gears & a 4-speed Muncie. I need to lower the RPM's so I'm going to change to 15's so my question is: Staying with B.F. Goodrich Brand, what size tires would be best Front & Rear? I'd like to keep the same low in rear end stance & I don't want the car to look like it's on steroids or those silly donks. Thanks for your help.

 

Here is a tire and gear ratio calculator to give you some ideas. There are many discussions on here on what tire and wheel combos work for your year model.

http://www.discounttire.com/dtcs/infoTireMath.do

http://www.angelfire.com/fl/procrastination/rear.html

 

If you go from your current 235 60 14s (25.1" tall) to 245 60 15s (26.6" tall) you will drop 200 rpm @ 70 mph. If you want to achieve a bigger RPM drop then you will have to go to a bigger tire out back. Next size up is 255 60 15s. Anything bigger than that will not achieve the look you want. 245s look good on all 4 corners to my eye when you want to be the same size all around.

 

245/60R15 is pretty much dead nuts the same diameter as the tires the factory installed. Their width might be a stitch wider, but they fit fine.

For what it's worth, on my '70 I have 275/60R15 BFG Drag Radials (28" dia) on back (chosen for traction) and 225/70R15 (27.4" dia) Goodyear RS-A cop tires on front (chosen to match rear dia and because they're a great tire). Both of these are about as large as you can go without interference and without looking funny (in my opinion).

If you want to cut your RPMs, change your rear gear or add overdrive.

 

Thanks for your reply's. I'm thinking on BF Goodrich 255/60/15's on all 4 corners. More opinions appreciated. Best place to purchase from? Brian

 

I always like to buy tires local, this way if there is an issue I can take care of it right away. Discount tire has treated me well here in Texas for man many cars. There may be one near you.