not sure how to calculate rolling diameter from the old description ( is the 7.50 the width or the section height ? ) but if that tire is the same height as a 235-75-15 then your revs work out to 3589 rpm. Of course a tire taller than the 235-75-15 would reduce the revs by the ratio of the tire heights and vice versa for a shorter tire.

Regards, john

 

Tires are 32" tall, the 7.50 is tread width.

 

http://www.pontiacracing.net/js_tire.htm try this site they have a good caculation program. i also have a hand held calculation wheel that i use for drag racing.

to answer your question a 32" Tire, 5.14 gears at 60 mph will turn about 3300 rpm

 

I really like 4:11s with a 27 inch tire and an AOD, accelerates like a SAA and cruises at not much more than an idle. sweet

 

an over drive is a very nice thing to have that's for sure

 

You doneeed no higher geerz esse... you need a bigger motor!

Pinche cabrone...

Taco power loco,
The Mad Fabber.

 

WOW! thanks guys for all the replys and links.

 

Well, ESSE.
i have a 460/C6 that i want to put in it. with the way gas prices are now. i could never afford to drive it.

Hey PUTO do i know you? por queue to eres un PENDEJO....LOL

 

With a 460/C6 you will want something around 2.80. Ive done a few of those swaps and the first time I started with a 3.50 and kept going taller until I got traction! That 460 puts out some serious torque.

One customer put on an Edelbrock intake/carb and a Jacobs ignition. Claims a steady 16-17 mpg towing a small boat with a 56 F100.
I cant do that good with a 292 Y block.

 

286merc, did that customer have 2:80 gears? If not, which gear est did he have? I just put a 9" housing into my 53 and have plans to put in a 460/C-6 combo into it. Then I'm towing my 67 mustang from Washington to Florida, so mileage is of importance.

 

Is it possible to find new rear end gears for a stock '56 rear end?

 

Yes. I would try Dennis Carpenter's catalog. They have almost anything in it.

 

I hang out with you for an afternoon and you forget about me!

Must be all that smoke you were breathing riding with Mike...

TheMadFabber.

 

Carl,

my calculations indicate 3238 rpm which is plenty close enough to the above answer. those taller tires do slow things down a bit.

Regards, John

 

286merc, did that customer have 2:80 gears?

Yes he does, I found them in a 73 LTD with a 460. Should be the same in big Mercs, Birds and Lincolns as the 2.80 was very common in them. However watch out for some 70's Lincolns and Birds as they use the 9 3/8 rear and they wont work in a 9" housing.