Hello,

What is needed to convert a 78 F150 with a 351M and a C6 to a 4 speed tranny? And what kind of work would it be to drop in a 460 later? Would it be better to swap both the motor and transmision at the same time? I apoligize for all the questions, I'm new.

Thanks,

Brandon

 

The switch to 4 speed is no big deal as long as you have all the parts. These include, transmission, bellhousing, flywheel, clutch, pressure plate, throwout bearing, pilot bearing, clutch fork, equalizer bar, upper and lower linkage rods, pedal, pedal spring, and assorted clips and bushings. You must also cut a hole in the trans cover on the floor or get the one that goes with the standard. The C6 is longer than the 4 speed, so a different driveshaft is needed also. Of course if your truck is four wheel drive, things are different. I converted a 72 F250 last year from C6 to NP-435. I collected all the parts before I began, it would been a whole lot easier if I had a parts truck with the correct parts, but instead, I found some parts in local classifieds, some junkyard, some ebay, some swap meet, and some still available from Ford. It was more work collecting the parts than making the swap and it was definitely worth it. As far as 460 conversion, this has been covered in detail in this forum, but if you keep the C6 it is nothing more than changing mounts, if you want the 4 speed, the same bellhousing can be used as the 351M but a spacer must be added between the bell and engine and some different flywheels can be used, such as 390. The 460 though changed balance in 79. It went from internally to externally so the flywheels changed. The clutch and pressure plate are another story, which I am not completely sure of, but it has been covered here before. I hope this helps.

JWR
72 F250 CS 390 NP-435
78 F250 4x4 400 NP-435

 

I just cant Imagine Why someone would want to Swap out an Auto for a Stick YUCK.

 

I am changing a standard to a c6 in a 74 highboy with a 390. my question is besides the driveshaft can I use the same crossmember where it is mounted now. or will it need to be relocated.

 

A few reasons i can think of:

Sticks can get better gas milage
Automatics suck a good amount of HP (I think i heard 60HP not sure)
Sticks are basically bullet proof

David

 

BigBully ~
A stick behind my built 460 and dual thrush mufflers would be just "plain-ole-fun" when running / wailing through the backroads of Georgia.

It's a blast now with the automatic, but there's just something about a close - ratio 4/5 speed under my sweaty palm and a wimpy S-10 sitting next to me ...

 

Yeah i forgot that reason. Standards are fun.
David

 

I dont think standards are fun and if you think you can outrun an Auto with a 4 speed Come up to my neck of the woods I want to show you what an Auto can do. A C6 that is built right will handle anything ya wanna throw at it and its alot cheeper to rebuild if it does crap the bed. BigFoot Monster truck runs a C6 and it puts out 1500 HP and has Won alot of races over the years.

 

[QUOTE]Originally posted by loveoldtrux
[Yeah I have a 460 under the hood and love when I see those chevy guys with the stickers downing FORDS that is when I open her up and blow them right off the road.] :-

 

Since auto are faster is that why (for the most part) they use standards in racing? Some think they are fun some dont.
Any way this is a pointless argument that has no help to the original question so this will be my last post on the thread.
David

 

In my 73 f250 4x4, I traded out my c-6 for a 435 4 speed trannie. I had to grind out therivets on the cross member and remount to line up with the trannie mounts using case hardened bolts.
Hope that helps.

 

This is full of good info guys. Lets not make it an auto vs. stick debate. I do race, and have raced both, and either has their merits. In my case, I do not wish to sink the cash into my C-6 that will make it live in my application....and then have to do it ever season or two like the "Bigfoot" guys. After pricing out a new flywheel, serious clutch, flywheel, etc. I found that the L&L kit is only a hair more expensive. Comes with your flywheel, pressure plate, and 12" clutch...all heavy duty enough to handle a 460. Also comes with the pilot bearing already ready to go. Since I can't really go cheap in my application it seems to make sense to go their route. I suggest you guys who are serious check out L&L. It can be done cheaper by the junkyard route but I can't get away with junker parts with my engine...

 

When I converted the 72 to 4 spd, I had to use a different crossmember because the c6 crossmember was different, they both bolted in though.

72 F250 CS 390 NP-435
78 F250 4x4 400 NP-435
85 F250 4x4 460 T-19

 

ive done the conversion in a 78 3/4 ton, u need a good bit, i just baught a whole other 4 speed junk truck to take everything out of.

 

If you want a 4 speed then thats your right and Im fine with that so dont get me wrong. I just dont understand Why most of the time. I have had guys say Oh its cheeper to Convert then to fix the C-6. Well I Have to Dissagree with that. I can Rebuild/Beef up a C-6 For around 100 Bucks and it will last for many years with hard use. Heck Im running One of my rebuilds Behind a 512CI BB and Plow snow with it. I Done it, Oh had to be like 8 or 9 years ago and still works like a champ. I had 2 others running Behind 460s and Not a problem with them. I had to take one out Because I converted to a Cummins and am now running a ZF5 speed in that truck. Believe me If I could Afford it that truck would have an E40D auto in it.