'42 flathead v8 - c4 setup

[str8axle63]

I have a 42 ford flathead v8 I want to install a c4 trans. Any bell house on the market that you would recommend ? Anyone use another auto trans you like?
Thanks for your help

[WABOOM]

Flat-O-Matic makes adapters for that.

[TJ]

Flat-O-Matic is your best bet. I used one and so did a friend and they work well. Also good tech support. They are located in Salem, Oregon.

[blucar]

Speedway has a complete conversion kit for a flat head V8-C4, including a rebuilt C-4 trans that has the required improvements.. One of Speedway's C-4 conversions is currently listed on eBay for $2,149.
You will have to convert your rear end over to an open drive line and parallel rear springs, Speedway has the conversion for an open drive line.
A friend of mine converted his '36 Ford 4dr sdn to a C-4 set up several years ago, a really neat set up. I have another friend that uses Ford C-4 transmissions behind Buick 320 CID straight 8 engines in lieu of the original Dyna-Flow.
A properly built up C-4 will handle 550 HP... This is a must do thing in order to work behind a flat head, it's not that they need the improvements to the C-4 for horse power, it's the other features, stall speed, etc., that are important.

[WABOOM]

Why do they need improvements? I was under the assumption that you could run a stock C4 behind a flathead.

[tubman]

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I think he missed a "not" in his post before "a must do thing". Just a guess. If that's not correct, I would also want to know why.

[str8axle63]

Me too, I would think it would be a straight swap, but I don't know much about flatheads . Also the truck has a two speed rear. Will this be a problem? Also does anyone know the price of the flat o matic ? Their website does not have much info.

[41Joe]

Their website says to call for pricing. 20 years ago, I purchased one from Flathead Jack and I believe it was $500.

[blucar]

Originally Posted by str8axle63

Me too, I would think it would be a straight swap, but I don't know much about flatheads . Also the truck has a two speed rear. Will this be a problem? Also does anyone know the price of the flat o matic ? Their website does not have much info.

Your original comments to this topic made no mention about the C-4 application being in a "truck", especially a truck with a two-speed rear end.
I don't think a two-speed rear axle would work very well behind a C-4 automatic.
I have a lot of friends that are still living in the past, building/modifying vehicles using mismatched parts that they harvest from a wrecking yard. When I was a kid I did the same thing. As I got older, I got smarter, opting for newer better parts/repairs that I did not have to work on all the time.
I don't claim to be a mechanic, I deal with people that are mechanics, that have the expertise to correctly fix things. In the case of a C-4 trans, or any other older automatic, they all have their own built in problems that could use some up grades in order to work a little more efficiently, in it's new application.

Reading the Speedway add for a C-4 flat-head conversion I noted that the kit even includes a 12v modified starter.

[Step-down]

Cling sells a adapter

[str8axle63]

Originally Posted by blucar

Your original comments to this topic made no mention about the C-4 application being in a "truck", especially a truck with a two-speed rear end.
I don't think a two-speed rear axle would work very well behind a C-4 automatic.
I have a lot of friends that are still living in the past, building/modifying vehicles using mismatched parts that they harvest from a wrecking yard. When I was a kid I did the same thing. As I got older, I got smarter, opting for newer better parts/repairs that I did not have to work on all the time.
I don't claim to be a mechanic, I deal with people that are mechanics, that have the expertise to correctly fix things. In the case of a C-4 trans, or any other older automatic, they all have their own built in problems that could use some up grades in order to work a little more efficiently, in it's new application.

Reading the Speedway add for a C-4 flat-head conversion I noted that the kit even includes a 12v modified starter.

This is both my first flathead and first 2 speed rear . So yes I should have been more clear. I put a c4 in my econoline when I built it, the motor is pushing 600 hp and its worked great in there. I was hoping it would also work with the flat head with way less hp. I know nothing about the 2 sp rear. I guess I need to do more homework

[TJ]

Is your "truck" a pickup or big truck? Is the 2 speed rear end a Columbia unit for a pickup or is it the big truck 2 speed rear?

[str8axle63]

I believe it would be considered a big truck. It is an original marmon herrington.
I just got it running after figuring out many electrical and fuel problems. I drove it for the first time and the transmission or the transfer case is making a serious noise and the truck has way to much tork . I was thinking I would take all the all wheel stuff out and hook up a c4 I have to try the rear end shifter and see maybe its in the low gear.
Im still feeling it out just thinking of different ways to go

[blucar]

If your '42 is a MH 4x4 it would be a shame to remove the 4x components, converting it to two wheel drive. The '42 MH 4x's are quite rare, and thereby would have significant value. A 2 speed rear differential in a 4x trk would be a very unusual option, I am not to sure just how it would work in four wheel drive, and if it would work at all.

If you have a C-4 in your Econoline that is pushing 600 hp, I'll bet that the trans has extensive modifications. I have been told that a good C-4, without modifications has become very pricey, just like the GM 2004R because of their adaptability behind large CID/HP engines.
If you are considering modifications to your truck, I would suggest putting the body on a late model chassis. You would still have an old looking truck with modern suspension, etc.
I recently did a conversion to a '64 pickup I have. I used a complete '98 chassis, eng/trans etc. Really made a nice unit, a pleasure to drive..

[mfirth]

I know of two different flathead/c-4 cars and the owners both say: Lack luster performance due to small torque converter. m

[str8axle63]

Originally Posted by blucar

If your '42 is a MH 4x4 it would be a shame to remove the 4x components, converting it to two wheel drive. The '42 MH 4x's are quite rare, and thereby would have significant value. A 2 speed rear differential in a 4x trk would be a very unusual option, I am not to sure just how it would work in four wheel drive, and if it would work at all.

If you have a C-4 in your Econoline that is pushing 600 hp, I'll bet that the trans has extensive modifications. I have been told that a good C-4, without modifications has become very pricey, just like the GM 2004R because of their adaptability behind large CID/HP engines.
If you are considering modifications to your truck, I would suggest putting the body on a late model chassis. You would still have an old looking truck with modern suspension, etc.
I recently did a conversion to a '64 pickup I have. I used a complete '98 chassis, eng/trans etc. Really made a nice unit, a pleasure to drive..

If I did go with a different trans I will take the all wheel drive stuff out but keep it all. I wont do anything that would prevent it going back to stock im really just trying to figure out the best way to go. I still have a lot to figure out with the truck

[Fourdy]

I have the Flat-O adapter with the C4 I rebuilt with a shift kit. I find NO lack luster performance at all. The blown 276 probably helps. LOL Seriously, it has been a pleasure to drive and performs exceptionally well.

[flatjack9]

Do they make a c-4 kit for an early engine, or does it have to go behind an 8BA engine? The Speedway kit would not work on an early engine, they specifically say "late" flathead.

[blucar]

Originally Posted by flatjack9

Do they make a c-4 kit for an early engine, or does it have to go behind an 8BA engine? The Speedway kit would not work on an early engine, they specifically say "late" flathead.

I am quite sure that someone has an adapter for the EFV8 21/24 stud engines. I know that a friend of mine put a C-4 behind a '36 21 stud engine in his '36 3dr sdn. Since the early engines have a bell housing cast into the block, and the C-4's have a bell housing that is bolted to the trans case, the adapter is most likely a flat plate that bolts to the engine block and the trans.


mfirth' comment about his experience with a C-4 behind flat head engines is most likely the result of just what I made mention in my original contribution to this topic. A stock C-4 behind a flat head engine needs a lot of help to make it work correctly.

[Bigmac48]

Just dreaming at this point but would u have to split the wishbones to install the speedway c4 kit in a 40 sedan with a 59ab flathead ? Thanks