F150 ****** with overdrive

bettlesr said:
By checking the tag on the one I drove in Florida and on mine and actually counting the ratios with the trans out on mine, they are both the 3.00 1st, 1.77 2nd, 1.00 3rd and .725 4th. this is the 37% trans. With the stock trans and the new engine I can easily start in second or go around corners without shifting. A lot better for the car and more fun to downshift though!
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37% would be .63 4th, or is my math wrong?
 
Thanks for the information will try to swap out the gears called cobra transmission today they are suspoist to get back with me any one have a cluster geer and fourth laying around would be intersted thanks
 
,if you want the .28% you will need an input shaft, overdrive gear and cluster. 22% you will need an overdrive gear and cluster. (both not easy to find) i have a complete 22% o.d. kit for sale,$2975.00+ shipping, (paypal only)
 
miss victoria, I think the way you're calculating the OD percentage is totally wrong. A transmission with a .7246 OD ratio means the engine turns .7246 revolutions and the drive shaft turns 1 revolution. So, when the engine has turned 1 full revolution, the drive shaft has turned 1.38007 revolutions. It is overdriven by 38%. So, a final OD ratio of .7837 = 27.6% and .7087 = 41.1%. There isn't a 22% OD transmission for that F150 tremec transmission. Please see my chart (post #8) earlier in this thread .
 
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chiliman, you may want to look into the 41.1% transmission further. The gear ratios in that transmission are; 1st = 3.006, 2nd =1.776, 3rd = 1.00 and fourth is .7087. Now if you do the math, with a 4.11 rear end ratio, the final drive ratios are 1st =12.35, 2nd =7.29, 3rd = 4.11 and fourth is 2.91. Compare this to a 3.78 rear and the 27.6% OD transmission and you get 1st = 12.28, 2nd = 7.25, 3rd = 3.78 and fourth is 2.96. Looks like the only big difference is 3rd gear, 4.11 verses 3.78. Using the 41.1% transmission is going to be way cheaper than buying all the guts you'll need to change it to a 27.6% OD transmission.
 
Pete said:
... have talked to at least 20 people that have the transmission in discussion and EVERY one of them said after driving it that they were not completely satisfied with the ratios. I noticed quite a few on this thread said the same thing...
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Talk to me, then that will ruin your 100% record!
 
Al in NY thanks for the in formation sounds like 41% with 411 rear end may be the way to go I have one of them scoped out for 200 dollars pulled the top off today at the reabilders gears all look good he is gona be ording the rebuild kit bearings scrnozer and shaft I may try it with the 378 rear first but Im thinking it wont have much power will keep you informed thanks agin
 
miss victoria, I wasn't recommending the 41.1% OD transmission, just trying to show you the correct way to calculate OD percentage.
 
fordgarage said:
The new aluminum F150 Model A clutch housing (Mac's?) I recently saw in Wisconsin did not impress me much. Great idea, but poorly executed.

They did not bother to index their new housing design to the Model A flywheel housing to insure or control the centerline alignment of the transmission to the flywheel.

All you guys that agonize over 'dialing in' the flywheel housing to the block can throw away all your fancy measuring tools and replace them with a Stanley tape measure when using the new F150 Model A bell housing I saw.
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Did the housing you saw have Macspeed embossed on it, because the Macspeed units here in New Zealand are superb quality, and there are a great number of them in use. I'm picking the one you saw was either some off brand or if it was a Macspeed it would have to be a rogue unit that slipped through. I have no affiliation with Macspeed, but Graeme MacNeill has a fantastic reputation for top quality work here in kiwiland.
 
I have been building thes F150 transmiissions for Model A Fords since 1998. I know these gear sets too. Al has the information right on the way to figure the OD %. Subtracting the .70 or .72 or .78 from 100 does not give a true OD %. Subrtacting onlly gives one a numerical figure not a %.

BTW I do not recommend the 41% for the Model A. The 37% only in very special conditions. I drive a 31 Model A coupe with the 27% and a 31 S/W Fordor with a 27% as well as a speedster with the same ******. I love the combo in all three cars.
 
The $500 price tag is probably why using the AA bell housing and fabricating a pedal mount is why the guys making the kits do it that way.
 
4th gear (Overdrive) is .78 which is either 22% or 27% depending on whose math method you use. The rear end ratio is stock Model A, which I believe is 3.78

From my experience, which is only about 1,500 miles, this combination is very acceptable, runs well under 2,000 rpm at 55mph.
 
Next question.... the adaptor plate to mount the torque tube to the trans... is this available, or does it need to be custom made? Also the u-joint... what is used here?
Thanks,
Marty.
 
There are kits avail from diff venues for this conversion, either 3 spd or 5 spd. Some require frame mods, some open drive, some closed drive. There's an ad for the conv in every hemmings mag, also ck on the HAMB.
Paul in CT
 
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