Flathead(8BA) Automatic Transmission Options/Question
 

Good morning all. First, I hope you are well. I’m looking to swap my 3 speed manual column shift transmission out (which I like driving) with an automatic transmission (just needs to happen). I am looking for a good, cost effective, bolt up match to my 255 8BA Flathead with Dana 41-3.92. My tires are 205’s instead of the 215 radial equivalents. I would like to maintain this rear end if at all possible. I typically do not operate this vehicle over 65-70 mph if necessary, but most of the time just cruising to spots on average 50-55 mph or less. Most of the threads (tons of helpful info, thank you…definitely got me started in this endeavor and right direction) I’ve searched mention these options…C4, C6, AOD, etc? My humble question is, which one without breaking the bank and will be safe, to operate within normal drivable limits. My apologies for all the rambling. Thank you kindly in advance for your knowledge, experience, and input. Stay safe, blessed, and be well.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

C4 is the easiest and sucks less horse power (25hp) to run and will handle 400hp. With the smaller converter from the earlier 170 inline 6 there is minimal to no trans tunnel modifications. The c6 is too big and the aod sucks lots of HP (50hp) to run
The other option is a c5 which is just a c4 with a lockup converter which will give better fuel mileage on long drives.
The c4 will give you close to the same top speed as your 3 speed. The OD of the AOD has the potential to give you a higher top speed but you most likely will never get the benefit unless you are flogging your engine assuming it’s stock at 85 hp minus the 50 to run the aod gives you less driving power than my lawnmower. But you can go full manual on the C4 C5 and AOD which will cut down the HP needed to run the trans but you will have to be shifting the gears and activating the OD and converter while you try to enjoy the drive.

I put a c4 in my current build with 3.55 diff and 31” tires will give me 70 at 2700rpm

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good morning…Sorry for the delay and thank you kindly for replying. Stock I’m at 110hp. This is great, just what I needed. Thank you so much for the assistance. I appreciate it. Have a safe and blessed rest of your day @ActionYobbo.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

I'm not quite ready for an automatic yet, but power steering sure would be nice.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

@Tubman…Definitely PS in the hopper on the to do list for sure. I just figured going auto now will give me some convenience. I just purchased my vehicle in March so I’m still going through it. Just recently finished a 12V conversion trying to plug away here and there at things.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Another option is a 2 speed powerglide. I have one in my totally stock 64 impala and is a pleasure to drive. The 2 speed sucks the least HP of any automatic and is also an option for the ford flathead with adapter kits available

Re: Flathead(8BA) Automatic Transmission Options/Question
 

@ActionYobbo…Thank you kindly for the follow up info. I did see that in one of the threads. I’m leaning more toward the C4 with my 110hp. Hopefully it’ll be ok. I’m definitely not trying to race or be speedy, I like hot rods in the mix, but not for this one. I had a 2 speed PF in my previous 1956 Dodge CR and it actually did great IMHO. I was going about 70ish and don’t recall ever having any concerns or complaints. It would zip down the interstates 😎. Never had the chance to dig into the ‘40 Plymouth transmission, but is was original, just don’t remember much about it. I think my top speeds were about 70. I appreciate your assistance.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

If you decide on a C4 you have a couple of options as far as the bell housing, flex plate, and torque converter
164 tooth flex plate v's 157 tooth. They are not interchangeable so you must stick with one style.
I have a 164t in a 1948. I love it!
What year is your car?

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good morning @69a. This was going to be my next question. As you can see novice in the transmission stuff. I have a 1950 Mercury. I think it has the 112 tooth but I’ll need to confirm this, I’m not sure. Thank you kindly for the information. I need to figure out what additional parts I’ll need should I pull this plug on a C4. Thanks again.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Here in Salem, Or is the C4 fellow, Nice building and location for these conversions. Google him. Good local rep. Newc

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good afternoon…First, I’d like to say thank you very much for the responses, your input, experiences, and knowledge. I purchased a C4 from a ‘65 Mustang. I am planning on still utilizing the column shift, well I’d like to. Now, to gather the “additional” items I’ll need. Thanks again, I’m grateful for the assistance and so quickly. Stay safe out there, blessed, and be well.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

@Newc …Thank you kindly. I will do that. I appreciate the info.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good afternoon. I tried searching him, but nothing came up with that name.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Hi. I'm fairly certain that you have a 157 tooth bell housing. Bolt the bell to the block and make sure the starter fits. I think you have to grind a little from the block (or starter) to allow it to fit perfectly. Once you have the flex plate bolted to the crankshaft do a trial fit with the torque converter and make sure it goes all the way in so that there is no gap between the studs on the torque converter and the flex plate.
There is a lot of information on a website called pigseye.com pm me if you can't find it and I will email you the info.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Oh, ok copy that. Thank you kindly for the instructions. This is great and will surely get me started. I appreciate it. I was just searching how to install and column linkage stuff. Thank you.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

I did several customer A/32/33-34 chassis over the years with 8BA motors my local machine shop built and either the C4 or AOD kits from Speedway. Both the motors and the trans worked good, no comebacks. Mostly used 3.25 rear gears for the C-4's and 3.78's for the AOD's.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Am I missing something? All the responses seem to indicate that the C4 will just bolt up. No mention of a install kit. Now I never did a C4 to flathead but I have done a C4 to a Yblock, and it will not just bolt up. A conversion kit is needed and the only one I know that has it is Flat-O-Procucts. I believe Speedway carries the same kit.


Am I wrong ?

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Awesome…I appreciate hearing this. I am hoping at some point once installed, I won’t have any comeback either 😌. I’ll check out speedway. I think I’ve come across the SW once at some point searching for other non related parts. Thank you.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

I called Gene from Flatomatics about a C4 conversion kit for a 1950 Mercury 255 8BA and left a vm. I couldn’t find anything on a website for them. Speedway, I will surely check out. Thank you kindly. I appreciate the info.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

No

It needs a Flathead to C4 flex plate, a bellhousing spacer and a starter adapter. Speedway sells a kit with those bits. Look up Flathead C4 kit and you will find what you need. Also depending on what you are fitting it into there is rear mount/crossmember modifications needed.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Awesome thank you…I’ve located on SW. Should I purchase a new torque converter? The transmission came with one.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

There is a combination of differences in torque converters. 24 or 26 spline and different diameters. If the one you have fits the conversion you could use it. So far I have been lucky and all my c4 parts were the correct ones for the conversion. I still need to get a starter
My adapter is similar to this (picture) except the adapter is welded steel. Got it at a swap meet . It’s got no markings so I don’t know where it was made.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good morning, ok copy that. I am going to attempt the bell housing and torque converter that came with this C4 first and adjust as necessary. I, too came across this picture that you shared and may find a kit as such. Thank you kindly for the information.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

The speedway kit is all you need. You have the option of either the 157tooth or the 164tooth kit. I believe your bell housing and torque converter need the 157 T kit. You need to verify this before you order it. PM me or google C4 auto identify and read the article on the pigseye.com website.
Read post #8

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good afternoon sir…Great, I was looking for this. I stumbled on this pigseye website and saved it because I figured it be useful reading, so thank you for confirming this. I appreciate you taking the time to provide this helpful info and all the others, thank you kindly.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Ran a Merc o matic for many years in a 40 International, Ran like a truck!!
Gramps

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Oh, how I wish I could have found or find one of these 😌.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

I’m pretty sure you are spot on. After reviewing the pigeyes, it appears certain it’s a 157t case fill C4. The only problem I’m having is decoding the tag found on the passenger side. It didn’t seem to line up with pigseye chart. I did read before that there could be various tags floating out there, so it may not seem so cut and dry.

(Tag)
PEE C
X 7F8 B2

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good evening…Thanks to the tons of helpful hints and knowledge on here and several spots I came across on the interweb as well, I think I was able to get close to decoding my C4…

PEE C = Mustang, maybe 289.
X = Not sure? Others seem to start with a “D”….
7F8 = June 8, 1967
B = Not sure? I’ve seen “Buffalo” on a search.
2 = Not sure? I’ve seen “2nd shift” on a search.

You guys are really solid on here. Thank you.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

If the "Mustang guys" are anything like the "Corvette guys" I know, decoding that definitively should be no problem.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Definitely…The guys on here and with alittle bit of research got me this far in one day and I’m grateful…I’m sure it’s only a matter of time. :)

Re: Flathead(8BA) Automatic Transmission Options/Question
 

You only need to know three things:
1). Bell housing style. 157 tooth is physically smaller than the 164, that is good. It also has the case fill box, which is also good, as the pan fill tube sticks out a lot further.
2). You need the torque converter to fit the matching flex plate, which I believe you already have, and this is confirmed by the stud spacing (PCD) of the 157T flex plate.
3). Drive shaft yoke. You will need this to adapt to your original drive shaft.
It is not difficult, you don't need to over think everything. Make sure you fit all the components to each other. Fit the torque converter to the gearbox. That should fit because it came with the box, correct?
Fit the flex plate to the torque converter, the studs should go all the way through.
You need the correct metal plate. speedway's will fit either bell housing as it has two sets of holes for the starter. You use the later starter (small block Ford).
Make sure the starter has clearance to the block. I think you need to grind a little off the block or starter. I used the V8 starter with the solenoid on the side and found the solenoid interfered with something (exhaust or chassis) I got a starter from a 6 cylinder and it has the solenoid at a different angle.

ps. Your adapter is just a flat crescent shaped 3/8" plate that has both the 8BA and SBF bolt pattern. It does not look anything like the adapter in post #22.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good morning…You are correct. I, too realize I maybe overthinking things a tad before even getting started, however first time doing transmission stuff with my vehicle(s) and just ensuring I’m taking all necessary and precautionary steps :). I need some woosah cruising wellness in my future :).

1. Yes sir
2. Yes sir, the torque converter came with the C4.
3. I will need to purchase this drive shaft yoke adapter. What am I looking for?

I will be purchasing the 157t kit from Speedway today. I am currently utilizing a Snap Rebuilders Ford high torque mini starter.

Is there a recommended shifter kit to be able to adapt to my column shifter? What does this entail? Based on most of the information reviewed, 1967 was a floor shifter. I’d like to use my column and stay somewhat with the original vibe if possible.

Thank you kindly for the instruction and guide. This is awesome information that I will surely use. I appreciate it.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

For the shifter limeworks makes a conversion that looks good. limeworks safety shift. How’s your fab skills? There is a few parts made from flat plate and some welding and drilling if you want to make it yourself

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good morning sir…Sweet, I’ll check out Lime Works. Minor fab skills on small items, nothing crazy, but I nevermind trying for some things. I suppose, since LW has one on the market, I’ll just secure one of these. Thank you for sharing this info. I appreciate the assistance.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

The starter you need is a Small Block Ford V8 or six cylinder equivalent. Read my post #32 about the orientation of the solenoid on the side of the starter. This starter bolts to the C4 bell housing.
You need the front portion of the driveshaft that goes into your C4 gearbox, or even a complete driveshaft.
Once your installation is completed you can put the driveshaft into the gearbox and see what you need to do to mate this to your diff. Measure the length you need to lengthen or shorten it. You probably need the shoe box back half and the C4 compatible front. You need to make it at least 1/2" shorter to allow for installation and suspension travel. Talk to your driveshaft guy, or someone here may advise. I made mine too long the first time and I couldn't get the driveshaft in.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Ok, copy that on #32. I do have the original starter laying around and understood. Ok, I see now in what you are saying with the drive shaft. Yes, for sure on the shops around here. Once I get most needed supplies, I will be connecting with one of our local transmission shops to weigh in as well. Thank you kindly for the additional info.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

F
Gramps

Re: Flathead(8BA) Automatic Transmission Options/Question
 

Good morning @Ol’ Ron…it’s seems difficult getting hands on a 50/51 Mercury auto, which would seem to be a more efficient solution. I would love to go this route, but I think the C4 once in place will do me right. Any advice on a drop in column shift steering column that I could bolt right in to utilize with my C4? Most columns seem to be 33” in length or shorter, which appears to be shorter than the original 50 Mercury column. I’ve been looking at some options. A couple search threads that I saw said the original 50 column can be used, but how with it being a column shift manual? Anyhow thank you kindly for the reply. Stay safe, blessed, and be well.

Re: Flathead(8BA) Automatic Transmission Options/Question
 

I sent you a PM with a link to another site showing how to convert your column to use it with the c4