The Ford Barn

50Trucking · 05-15-2025, 10:40 AM

I am building A 31 coupe for Street and Strip. I have acquired most of the parts for the engine build which consist of .80 oversized pistons, 1.70 intake valves, a Brierley cam, 6.5 head, dual strongberg 81’s, reds headers and a FSI centrifugal distributor. I plan on using a 39 synchromesh 3 speed tranny with lightened flywheel and V8 clutch.
I am running 1936 Ford 16 inch wheels with 6:00x16 tires.

This brings me to the rear end and what ratio will be best suited for both track and street. I plan on racing in the race of gentlemen which is on the sandy beach of Wildwood NJ.

I am looking at a 325:1 which will give me good road speed but wonder if that is too high for drag racing on the sand at TROG. I notice most guys start in second gear in the sand but with the 39 synchromesh tranny with a 1st gear ratio of 2.82 and a second gear ratio of 1.607, it could make up for the higher rear end ratio by starting in first and speed shifting with the fully syncro trans.

What are the thoughts of the Ford Barn Guru's that have a lot more experience at this that I do.

Are there others I should look at? I would like a quick change unit but they are very expensive and hard to find.

alexiskai · 05-15-2025, 11:04 AM

This is one question you might think about asking over on the V8 forum, only because those guys have a lot more experience with the kinds of mods you're using here.

fastone371 · 05-15-2025, 12:09 PM

I'd stick with the 3.25:1, solid compromise for both road and sand if you're running that trans.

nkaminar · 05-15-2025, 01:43 PM

What about running a quick change rear end? That way you could change ratio at the track depending on results.

Bob C · 05-15-2025, 02:03 PM

How about a Mitchell Overdrive.

alexiskai · 05-15-2025, 02:18 PM

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Quote:

Originally Posted by nkaminar

What about running a quick change rear end? That way you could change ratio at the track depending on results.

OP says, "I would like a quick change unit but they are very expensive and hard to find."

Hitman · 05-15-2025, 03:02 PM

Tell us more about the street side of the use. How fast do you want to go, how long do you want to go at those speeds? What engine rpm are you building for?

A 3.27:1 is a tall gear, you'll can get up to 40-45 mph in second with a built engine. That's probably too tall to start off in 2nd with a 3.27.

Phil Brown · 05-15-2025, 08:53 PM

https://www.pacificquickchange.com.au/
Not hard to find if your ok with a new one.

nkaminar · 05-16-2025, 08:14 AM

Many years ago I built a small solar cell powered car for a drag race contest. The contest was sponsored by Sandia National Labs and was part of a conference. They provided the cells and motor.

Among other innovations, my car had a variable speed transmission consisting of audio tape (remember those?) that wound between two pulleys. The tape started out on the output pulley on the rear axle and the input pulley, attached to the motor, was bare. As the tape wound onto the pulley on the motor and off the pulley on the axle the ratio would change.

My car was at least twice as fast as the other cars.

I am just wondering if something like this could be used for 50's drag racing. Maybe a steel tape could be used. A solid axle could be used with a large pulley on it. A differential is not needed for drag racing. In my mind I see another pulley attached to a right angle gear system which is lined up with the pulley on the axle. Of course this could only be used for racing.

What do you think?

Phil Brown · 05-16-2025, 10:03 AM

Quote:

Originally Posted by nkaminar

Many years ago I built a small solar cell powered car for a drag race contest. The contest was sponsored by Sandia National Labs and was part of a conference. They provided the cells and motor.

Among other innovations, my car had a variable speed transmission consisting of audio tape (remember those?) that wound between two pulleys. The tape started out on the output pulley on the rear axle and the input pulley, attached to the motor, was bare. As the tape wound onto the pulley on the motor and off the pulley on the axle the ratio would change.

My car was at least twice as fast as the other cars.

I am just wondering if something like this could be used for 50's drag racing. Maybe a steel tape could be used. A solid axle could be used with a large pulley on it. A differential is not needed for drag racing. In my mind I see another pulley attached to a right angle gear system which is lined up with the pulley on the axle. Of course this could only be used for racing.

What do you think?

Interesting concept

Ruth · 05-16-2025, 11:19 AM

Kinda like the variable speed used on Rokon Motorcycles and snowmobiles?

Fullraceflathead · 05-16-2025, 11:50 AM

That's 1 hell of a neat idea using an audio tape a cassette tape I'm assuming as a variable speed transmission in a small car application I'm gonna have to remember that!!!

Jim Brierley · 05-16-2025, 12:36 PM

I ran a 3.27 rear in my speedster for awhile, and didn't like it. Starting from a start was not good, on the highway was great. Trying to race it, you'd lose right at the start!

05-15-2025, 10:40 AM	#1
50Trucking Member Join Date: Sep 2020 Location: St Augustine Fl Posts: 56	Rear End Ratios for STREET & STRIP I am building A 31 coupe for Street and Strip. I have acquired most of the parts for the engine build which consist of .80 oversized pistons, 1.70 intake valves, a Brierley cam, 6.5 head, dual strongberg 81’s, reds headers and a FSI centrifugal distributor. I plan on using a 39 synchromesh 3 speed tranny with lightened flywheel and V8 clutch. I am running 1936 Ford 16 inch wheels with 6:00x16 tires. This brings me to the rear end and what ratio will be best suited for both track and street. I plan on racing in the race of gentlemen which is on the sandy beach of Wildwood NJ. I am looking at a 325:1 which will give me good road speed but wonder if that is too high for drag racing on the sand at TROG. I notice most guys start in second gear in the sand but with the 39 synchromesh tranny with a 1st gear ratio of 2.82 and a second gear ratio of 1.607, it could make up for the higher rear end ratio by starting in first and speed shifting with the fully syncro trans. What are the thoughts of the Ford Barn Guru's that have a lot more experience at this that I do. Are there others I should look at? I would like a quick change unit but they are very expensive and hard to find.

05-15-2025, 11:04 AM	#2
alexiskai Senior Member Join Date: Apr 2018 Location: Mebane NC Posts: 2,848	Re: Rear End Ratios for STREET & STRIP This is one question you might think about asking over on the V8 forum, only because those guys have a lot more experience with the kinds of mods you're using here.

05-15-2025, 12:09 PM	#3
fastone371 Junior Member Join Date: Aug 2019 Posts: 10	Re: Rear End Ratios for STREET & STRIP I'd stick with the 3.25:1, solid compromise for both road and sand if you're running that trans.

05-15-2025, 01:43 PM	#4
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,859	Re: Rear End Ratios for STREET & STRIP What about running a quick change rear end? That way you could change ratio at the track depending on results. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

05-15-2025, 02:03 PM	#5
Bob C Senior Member Join Date: May 2010 Location: So Cal Posts: 9,359	Re: Rear End Ratios for STREET & STRIP How about a Mitchell Overdrive.

05-15-2025, 03:02 PM	#7
Hitman Senior Member Join Date: Sep 2014 Posts: 822	Re: Rear End Ratios for STREET & STRIP Tell us more about the street side of the use. How fast do you want to go, how long do you want to go at those speeds? What engine rpm are you building for? A 3.27:1 is a tall gear, you'll can get up to 40-45 mph in second with a built engine. That's probably too tall to start off in 2nd with a 3.27.

05-15-2025, 08:53 PM	#8
Phil Brown Senior Member Join Date: May 2010 Location: Santee Calif. Posts: 638	Re: Rear End Ratios for STREET & STRIP https://www.pacificquickchange.com.au/ Not hard to find if your ok with a new one.

05-16-2025, 08:14 AM	#9
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,859	Re: Rear End Ratios for STREET & STRIP Many years ago I built a small solar cell powered car for a drag race contest. The contest was sponsored by Sandia National Labs and was part of a conference. They provided the cells and motor. Among other innovations, my car had a variable speed transmission consisting of audio tape (remember those?) that wound between two pulleys. The tape started out on the output pulley on the rear axle and the input pulley, attached to the motor, was bare. As the tape wound onto the pulley on the motor and off the pulley on the axle the ratio would change. My car was at least twice as fast as the other cars. I am just wondering if something like this could be used for 50's drag racing. Maybe a steel tape could be used. A solid axle could be used with a large pulley on it. A differential is not needed for drag racing. In my mind I see another pulley attached to a right angle gear system which is lined up with the pulley on the axle. Of course this could only be used for racing. What do you think? __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 05-16-2025 at 08:20 AM.

05-16-2025, 11:19 AM	#11
Ruth Senior Member Join Date: May 2016 Location: Glide, Oregon Posts: 1,441	Re: Rear End Ratios for STREET & STRIP Kinda like the variable speed used on Rokon Motorcycles and snowmobiles? __________________ Ruth "Sometimes you really DO need to read the whole thread"

05-16-2025, 11:50 AM	#12
Fullraceflathead Senior Member Join Date: May 2012 Location: Chillicothe, Missouri Posts: 1,684	Re: Rear End Ratios for STREET & STRIP That's 1 hell of a neat idea using an audio tape a cassette tape I'm assuming as a variable speed transmission in a small car application I'm gonna have to remember that!!! __________________ "If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask

05-16-2025, 12:36 PM	#13
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,251	Re: Rear End Ratios for STREET & STRIP I ran a 3.27 rear in my speedster for awhile, and didn't like it. Starting from a start was not good, on the highway was great. Trying to race it, you'd lose right at the start!