Technical Flathead to C4

Does anybody know if the C4 out of an old flathead Jeepster will just bolt right up to a 50 flathead block?

 

When did a Jeepster come with a C4 trans?

 

If you want to put a C4 behind your flathead, Gene at Flat-O Products knows more than most and has the adapter you need. Check him out.
https://flat-o.com/car-products/flat-o-matic/

 

I have a friend that was talked into putting a c4 behind his flathead by a shop and is now a little disappointed. Tired flathead and the inherent parasitic draw of an auto. If you Must go auto think 4 speed auto . 2004r or similar . Still a bit parasitic but at least it’s Highway friendly.

 

I've got a chemical induced loss of all peripheral vision thanks to my Uncle Sam so they don't let me drive anymore as a reward for it. Because of that my chauffeur wants an automagic.
I'm building my truck for therapy, just to stay sane. I did buy a built 1950 Mercury Flathead, the one in my avatar, from a mans estate in NJ and it came with all the paperwork.
The truck is all set up for a flathead with a C4 already, and I've been told a 2600 stall converter can help offset some of the parasitic effects of the auto on the flathead. I guess this will remain to be seen.
The reason I asked about the C4 in a Jeepster is someone has one for sale on Craigslist that came out of a jeepster behind a flathead ford V8, which means it was probably a WW2 Jeepsteer that the guy did an auto swap on. I emailed the guy and he said it was a mustang transmission.

 

If you can post pictures of the transmission he has for sale, and all the parts it comes with, someone might be able to help you figure out if it would work for you.

The little bit of info you provided won't tell us enough to answer your question.

 

Speedway has the entire kit with a brand new transmission included for almost the same as he wants so it's a moot point and I think I found the 2 best solutions in Flat-O and Speedway. You did help. Thanks.

 

Hi,

C4 to flathead has been done many times but you might want to get some additional advice before going with a 2600 stall on a street flathead. Street flatheads don't rev like a small block chev, or later motors and in my view will be a pig to drive with that much stall. No doubt the flathead could maybe use some stall but 2600 is a lot. I have a 408 windsor motor with a 2400 stall and I wouldn't want that high a stall behind my 260 CI merc crank, 2 carb flatty.

 

I used a speedway c4 kit in a 33 coupe with a stock 8cm.i was disappointed to say the least but the customer was happy.had 3.70 gears and 31 in tires in rear and was a slouch.had a stock converter maybe a better converter would have helped. The kit worked easy for what it's worth

 

i put a c4 speedway kit in my '32 bantam altered '53 ford flathead with a 2000 stall convertor. it has 4.10 in rear and runs just fine. it could easily run on the street. i.e it's slow as hell!

 

Personally I don't see any point. The stock manual gearbox is a 3 speed. The c4 is a 3 speed. Both have 1 to final drive. But the c4 drains hp from the already low hp motor to run.
So unless you have problems with a clutch the is no benefit.

 

I guess you missed post #5.

 

What does the flatty have on the build sheet? Bone stock or something 'special'? In stock form you have similar hp to the old Mopar L6 engines and many have used a Torqueflite or a GM trans and had reasonable success.
All automatics have internal parasitic hp losses...something has to drive all of the internals. The trick is finding the one with the least lost hp and figure out if it can be made to work.

 

Remember, Few read entire posts before commenting. Once a trigger point is hit, the typing begins.

 

Mills MA, to about anywhere in Connecticut is not all that far!

 

I'm surprised with the concerns that the C4 consumes too much power for a flathead V8.
Years ago we put one behind a 200 six in a 1963 Falcon and it seemed pretty good.

 

I have driven a flatty for some years with an auto. I certainly do not have problems keeping up with the traffic.
My trans is a four stage, with overdrive top, and lock up converter from a Toyota!! Installed using an Australian kit.
Will the Ford o/d auto work with the kits available for C4??
Raer end gear is important, I would suggest something around 4 or 4.11. This should give an open rod cruise at 2000 / 2500 rpm. Use some basic arithmetic to calculate top gear rpm from tire cir***ference, rear end gear ratio ang trans overdrive at your chosen cruise speed.
FWIW my engine is a C29A, ex military, bored 040", mild Schnieder cam, Edmunds heads, and a wee four barrel.
Later transmissions tend to have a lot of wiring and computer control. Go for an earlier type that will happily work independently, possibly with a lock out switch for 4th (o/d)

 

I guess I did.

 

Flat attack down here manufacture a kit to adapt a Toyota Crown / Cressida OD transmission to a flattie. $USD to $AUD isn't a bad exchange rate today

 

Those would be a rare find to source from in the US.

 

We only got the Crown here from I want to say 1955 (It may have been 1959 I don't remember) to 73 and we just now got it again in 2023.
I would imagine the transmission you are talking about was probably in the 1980s?
Any idea on what the transmission model is actually called and when it was made we had a few rear drive Toyota's here.

 

I don't recall specific years however it was a popular imported RWD model. An old friend built a 33/4 coupe years ago and used this setup behind the flathead. I gather that North American based distributors would know specifics

Flatattack Racing Products, U.S.A. west coast distributor is, Red’s Headers
31 – 410 Reserve Drive, Suite 4 Thousand Palms, Ca 92276
760 343-2590
info@reds-headers.com

Canada
David Love Cloverdale Speed Shop,
Cloverdale BC Canada 604 454 4010
davidclove@shaw.ca

 

The C-4 was not introduced until 1964 and, to my knowledge, no jeepster ever came with a Ford Flathead V-8. Certainly not during WWII.

 

Sorry to stray a bit sideways but what type of loss was noted from the Fordomatic or whatever that auto was behind the later flat head motors?
There was a thread here with the losses of the popular automatics but I'll never find it.
D

 

I used the Flatattack kit. The Aisan A340 series o/d auto was used in various models of Toyota Crown, Cressida, Supra and others. Also used on some rwd Volvo models. Do an internet search fo a full list.

 

I've been reading the comments about the automatic robbing so much power. Back in the 60's I traded for a 52 or 53 Ford with a Ford-O-Matic. The stock flathead engine ran well but was pretty worn out. It wasn't a hot rod, but it didn't have any problem keeping up with traffic. I thought it had sufficient power.

 

I've used the Toyota 4 speed/Flatattack kit a couple of times. (not for me)
I have also driven one. It was a restorers car, a 32 roadster on 35 wires. Restorers do funny things sometimes when they modify stuff. This roadster had a well built 59A engine and the Toyota 4 speed and it was a real slug to get going, but I'm not going to blame the engine or transmission. The guy thought he'd be clever with an open driveline and used a late model diff of the right width...and a 2:78 ratio. He never thought about that and blamed the engine builder for the sluggish performance.

 

I did the Speedway c-4 kit to my Flathead. As did a lot of my friends. No regrets at all.

 

The 3 speed toploader in my '39 p/u came from a local shop owner who took it out of a gorgeous '39 convertible. Got to the point where shifting became too difficult and he could not longer enjoy driving it anymore. Solution was a C4 swap. Problem solved.