Has anyone here put a conversion kit on their flathead to run an auto tranny? If so what parts needed to be changed out to make it work?

 

Do you want an IFS, an auto trans or both? Which flathead do you have, ie is it a '48-'53 block or an older one?

 

I would like to find a bolt on IFS, I heard the 48-52 Mustang II kit will work? Not sure on the engine, I believe the block is a 48-53 though. Which is more cost effective, to run a 302 and a c6 or keep the flathead and try to hook it up to an auto tranny?

 

I don't think you are going to find a bolt on IFS. The MII style is one of the more common, it will require welding in most of the parts. Before you attempt it, or have someone do it for you, do some reading. I am not planning on doing an IFS for my truck because when I get done, I want an old truck :-) I do understand why people want the IFS though. The MII style are sold be several vendors. Most of the kits have some weak points as I have read. I recommended this thread earlier its a pretty good read. The guy that started the thread is not opposed to doing MII for his customers, but he has supposedly repaired enough of them to know their weak points and throws in a few good picts along the way:
http://jalopyjournal.com/forum/showt...ht=mustang+ifs

If you use the search function on that forum with "mustang+ifs" you can read for days about home made, some alternatives, and the different places that make the kits -- I think the guy that wroe the above thread actually recommends the Dakota IFS because of the weight differences of the cars and trucks, and of course I think he may even sell parts.

I think you can get an adapter kit for the auto trans for either of the flatheads (early or late) but I will need to check again -- someone else might answer before I can get some info. I think you want to stick with the C4 though, its plenty tough enough for the flathead and will lose less power. The stock flathead is about 100 HP and you can make some gains off that, but to get to the starting end of the 302 will cost a lot of money (FlatHeadsForever) Does your flathead run?

 

I forgot to mention that it is correct that the MII kit for the '48 trucks will fit the the '46, they have basically the same frame rails where it counts.

Speedway motors sells a basic adapter for the '48-'53 engine to an AOD or C4 trans, from this it looks like you will need the slip yoke, starter and a shifter, there is a link to their instructions on the page for more details:

http://www.speedwaymotors.com/Flathe...Kit,11051.html

Flat-O-Matic has a conversion kist for the older style engine (although it could be used on the newer engine -- you probably have the extra parts you would need for this if you have the '48 style engine and the '46 style trans). They also have some other good reminders in a link on the page and some instructions you can read through. It looks like this kit is limited to the early autos though, as their special torque converter will not match the newer ones. Check with them though, they might have something for the newer AOD as well. This kit uses the flathead starter, but you still need a slip yoke and shifter.

http://www.flat-o.com/carproducts/flatomatic.htm

Then of course you will likely need to modify the trans mount in the truck to fit the trans.

 

Sorry, with the Speedway adapter it looks like you need the bell housing from the auto that you get for the conversion. I assume the bell needs to be a 302/5 liter style, I didn't dig into the lit enough to know. I know that I did a swap on a 302 once where I had to put the smaller flexplate on the car -- the torque converter had a smaller bolt pattern, but the bell bolted up fine and the old starter worked fine. The slip yoke from the donor trans can be used as well for both adapters. Finally you will need to to have a driveshaft made to fit since the new trans is longer than the old.

 

Just to see the work involved, I have some shots related to installing a Fatman Fabs IFS in the following forum:

https://www.ford-trucks.com/forums/8...way-guide.html

Is it a pain, sort of

Is it $$ - kind of ~ $2000 with some of the bells a whistles

Is it worth it - A lot better feel driving, and the bumps don't act like they will shake the truck apart!

But many like the original feel, but I was going with a big block and was concerned with the higher weight and capability of the shocks.

Just my $0.02 worth..

 

cody919, I installed a bolt-on MII crossmember on my 46. It was from Chassis Engineering. Look it up and send for a free catalog. I used the one for a 48 and it bolted right on. Also used their A arms and disc brake set up. Had to drill a few holes. I also used their rear spring set up. Had to cut quite a few rivets though. I'm in the process of installing a 302 Mustang engine with AOD the engine mounts were pre welded on the crossmember. Had to cut out the original Trans mount because the trans was so wide. I bought a brake pedal assembly from speedway that was suspose to fit a 53-56 ford frame mount. it bolted right in place with a couple of holes to drill. I'm using MP Brakes power brake and master cyl. that bolts on to that pedal assy. You can also get it from speedway. i'm also using a speedway trans mount crossmember made for a 53-56 frame its exactly the right width. Sometimes you have to be innovative to reach your goal

 

Thanks so much for all the info!

Im also toying with the idea of throwing a 302 in there because I do have an extra one, but it seems like everyone I talk to wants me to stick with the flathead, any opinions? Do you have to cut the firewall at all to make the 302 fit?

 

Did you post a thread on here about this IFS? For some reason now that you post this I am thinking I do vaguely recall someone asking a bout someone finding and wanting to use a bolt on IFS. What do you think of the overall quality?

Could you have used the old crossmember / pedal assembly at all? Is the pedal assembly from speedway under the cab like the stock one? If so how far behind that assembly is the new transmission crossmember -- does it make a tight fit for the master cylinder and power booster?

Although I am going trying to stay stock on my truck I find all of this interesting, I think these would be questions that cody919 would be interested in as well if he wants to do something similar.

 

Well, cody, the 302 should fit in without modifying the firewall,but its not an easy fit. You will have to use the 6 cyl pos. radiator mount at least I'm going to in my set up. I'm going to use the EFI setup also but you can use the carb if its an older engine. Staying with the flathead in fine, a lot of folks do. I just want modern convenience and reliability.

soule46. I probably have posted this information before its been a while. When I purchased the IFS I took a trip up to Iowa where they Mfg these things and toured the factory. I was impressed with the quality and fit. They treated me very well.
I removed all of the original pedal cross member. Yes its an under floor pedal assy. The trans crossmember sets just in front of the power unit the master is behind that. It all tucks inside the frame rail. Its hard to explain if you haven't seen it. I have heard that you can cut the center of the original cross member and weld in a shelve to support the trans. There is a bracket adapter you can get from MD brakes that will bolt behind the original pedal assy. in order to use a power set up. All this stuff isn't cheap. I've saved several years to be able to purchase