The Ford Barn

3739ford · 11-05-2017, 07:01 AM

I will be in the future putting together a 255 engine and mating it to AOD transmission. The 39 Ford truck currently has 4:11 gear ratio. I want an all around daily driver that performs both in town and out on the highway/interstates.

I would like to know what some of you are running.

Moultrie Swap Meet is in two weeks and depending on feedback I could look for different ratio ring gear and pinion.

TJ · 11-05-2017, 10:15 AM

I would opt for a 3.78 ratio.

texas webb · 11-05-2017, 11:23 AM

Yep^^^^^.

Dave Castle · 11-05-2017, 09:30 PM

My 40 has a 3.78, seems perfect

fordor41 · 11-05-2017, 10:00 PM

I believe a 302 would be a better choice but anyway I ran 3:78's with my 302 and it worked ok. Now I have 2:75's. a bit low on torque at the bottom but sure can pass gas stations on the hi-way!

alanwoodieman · 11-05-2017, 10:25 PM

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how are you mating the AOD to a closed driveline? are you going to put an open driveline in the truck? if so put in a 9" ford truck rear axle and you can easily change out gear ratio's

tubman · 11-05-2017, 10:45 PM

Wait a second. When he mentioned a "255", i just assumed that he was referring to a Merc flathead. I kinda thought the AOD was bit unusual, but what the hey? Maybe he isn't going to run a flathead at all, which changes everything. I think we need some more definitive information before we can help.

He also mentions replacing the "ring and pinion" which means he either has a different rear end in it already or is getting into a flathead to AOD to torque-tube banjo situation, which may not be pretty.

Alaska Jim · 11-06-2017, 01:28 AM

Yes. is he using a small block ford 255v8 that was available in the 82 thunderbirds , as well as other models of that era, or, is he using a 255 Merc. Flathead? Makes a big difference in engineering the rearend and drive shaft.

3739ford · 11-06-2017, 08:26 AM

It is a Merc engine and I plan on open driveshaft. I was planning on keeping the original banjo rear end. I already checked with Speedway they have everything I need to go with AOD.

Ol' Ron · 11-06-2017, 08:44 AM

The AOD conversion requires some block modification for the late starter. Depending on the application, I'd keep the 4.1 rear. I have a friend with one, we live in Vt. so that works well, and the engine revs are quite low in the 60/70 MPH range.

11-05-2017, 07:01 AM	#1
3739ford Senior Member Join Date: Feb 2017 Location: Dothan, AL Posts: 325	Need some feedback I will be in the future putting together a 255 engine and mating it to AOD transmission. The 39 Ford truck currently has 4:11 gear ratio. I want an all around daily driver that performs both in town and out on the highway/interstates. I would like to know what some of you are running. Moultrie Swap Meet is in two weeks and depending on feedback I could look for different ratio ring gear and pinion.

11-05-2017, 10:15 AM	#2
TJ Senior Member Join Date: May 2010 Location: Napa,California Posts: 6,037	Re: Need some feedback I would opt for a 3.78 ratio.

11-05-2017, 11:23 AM	#3
texas webb Senior Member Join Date: Dec 2010 Location: San Antonio Texas Posts: 636	Re: Need some feedback Yep^^^^^.

11-05-2017, 09:30 PM	#4
Dave Castle Senior Member Join Date: Jun 2017 Location: Carmel, Ca Posts: 269	Re: Need some feedback My 40 has a 3.78, seems perfect

11-05-2017, 10:00 PM	#5
fordor41 Senior Member Join Date: Oct 2011 Location: elmira,ny Posts: 1,518	Re: Need some feedback I believe a 302 would be a better choice but anyway I ran 3:78's with my 302 and it worked ok. Now I have 2:75's. a bit low on torque at the bottom but sure can pass gas stations on the hi-way!

11-05-2017, 10:25 PM	#6
alanwoodieman Senior Member Join Date: May 2010 Location: upstate SC Posts: 2,965	Re: Need some feedback Sponsored Links (Register now to hide all advertisements) how are you mating the AOD to a closed driveline? are you going to put an open driveline in the truck? if so put in a 9" ford truck rear axle and you can easily change out gear ratio's

11-05-2017, 10:45 PM	#7
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,320	Re: Need some feedback Wait a second. When he mentioned a "255", i just assumed that he was referring to a Merc flathead. I kinda thought the AOD was bit unusual, but what the hey? Maybe he isn't going to run a flathead at all, which changes everything. I think we need some more definitive information before we can help. He also mentions replacing the "ring and pinion" which means he either has a different rear end in it already or is getting into a flathead to AOD to torque-tube banjo situation, which may not be pretty.

11-06-2017, 01:28 AM	#8
Alaska Jim Senior Member Join Date: May 2010 Location: Palmer, Alaska Posts: 1,575	Re: Need some feedback Yes. is he using a small block ford 255v8 that was available in the 82 thunderbirds , as well as other models of that era, or, is he using a 255 Merc. Flathead? Makes a big difference in engineering the rearend and drive shaft.

11-06-2017, 08:26 AM	#9
3739ford Senior Member Join Date: Feb 2017 Location: Dothan, AL Posts: 325	Re: Need some feedback It is a Merc engine and I plan on open driveshaft. I was planning on keeping the original banjo rear end. I already checked with Speedway they have everything I need to go with AOD.

11-06-2017, 08:44 AM	#10
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: Need some feedback The AOD conversion requires some block modification for the late starter. Depending on the application, I'd keep the 4.1 rear. I have a friend with one, we live in Vt. so that works well, and the engine revs are quite low in the 60/70 MPH range.