Transmission gears ratio w/ flathead??

This might help? In my 51 F1 I have a warmed-up FH behind that is a close ratio BW T-19 and it has the same gearing as the T-5 minus the OD gear. I have 3.50 gears in my 9in. The truck weights in @ 3300 lbs. On flat ground the truck pull thru the gears no problem. So at 60mph I cruzing about 2500 rpm. Put a hill in the mix and I'm wishing for a 3.70 gear. So if the truck was a 1000 lbs. lighter the 3.50 would be great and you could cruz all day long @ 2000-2500 rpm @ 75 mph. Keep in mind I'm a mile up and lots of hills.

 

come on there has to be someone here running the same set-ups! roadsters are a dime a dozen....lol

 

A friend of mine had a 87 S15 that came from the factory with the 2.5L 4 banger (may have put out 100hp if it was lucky), T-5 trans, 3.73 gears. It was somewhat peppy with the 2.5L, but test drove another one with a 2.5L, T-5, & 3.40 something gear and it was gutless, couldn't use OD unless you were going over 80 mph on a flat hwy, had to put it back in 4 gear to go up a hill.


Is it for hwy, city, or both? What is the rpm powerband for the camshaft?

 

You are comparing apples to oranges. You are trying to compare how a 100 hp 4 cyl. runs compared to an ~ 200 hp 8 cyl.

Use the 3.0 to 3.23 or so. The .86 OD isn't shit for an OD, take my word for it, and the 4.03 first gear will work fine with those gears.

 

ok 50FORD1963.........3.23 IT IS.....hope your right...lol

unless someone else has another idea...lol

 

i think that my T5 is a .72. with 16" wheels, a 4.57 gear and tall tires, it cruises well on the highway but my 235ci can't take much more of an overdrive, especially going into a headwind. i think a 3.73 would be fine for your application.

where did you get that nice T5? it looks new....

 

are you kidding me....lmao

 

I wasn't comparing a 100hp engine to a 200hp engine, I was comparing a 3.73 gear to a 3.40 gear.

Also note the question I asked about rpm powerband for the camshaft, and where will it be drivin mainly? city, hwy, or both?

I think a 3.50 gear would work good.

 

A 3.54 ratio rear and 31" 750X16 @ 70mph = 2685rpm
3.78 ratio rear 750x16 @ 70mph= 2867 rpm

throw in a .72 O/d s10 box 3.78 @ 70mph = 2048 rpm
3.54 @ 70mph = 1933 rpm

I am just wondering if the rpm in these figures are a bit on the low side for a anything under 70mph. I am imagining the flatty will lug a little if you change to 5th at say 55mph with the 3.78 ratio at 1600 rpm. Though a 29" tire will bring it up to 1700 rpm
Great for economy but might be below the best torque range. Will sure need to go to 4th gear on any hill .