My 400 recently broke an exhaust valve and the cylinder is beat up really bad. I dont' know if I'm able to sleeve it and an alternate 400 has been tough to find. I have found a few people with a 460 motor. My question is Will a 460 bolt up to a c-4 transmission? If so can I use the same torque converter and what would the MPG be around?

 

A c4 behind a 400? Is it a removable bell with an iron case? Or aluminum case? Or all one piece aluminum?

In a light vehicle this might work, but in a truck.....?

As to torque converter, don't know, MPG would depend on which 460 and what you did to it, but probably about the same as the 400.

 

I bought the truck at auction. It's a 92 F350 which was modified to accomodate this 400 / c4 tranny combo. My research depicts the 460 and diesel motors were what was in it originally and I just recently had the tranny all redone so I need to use it. If not I will just continue to search for another 400.

 

Are you sure its a c4 and not a FMX? A C4 has 11 bolts in the pan, removeable bell housing with an aluminum center case. A FMX has 14 bolts in the pan, Removeable bell housing with a cast iron center case. 99.9 percent of the 400's have the same bell housing bolt patern as the 460. There were some made with the small bell housing patern but very rare. The c4 is a great trans for a car and withstands big horsepower. Not sure if you can find a good torque converter for a truck set up. Lots of racing ones are available though. If it was me I would sell that trans and get a C6. Then you would be basically trouble free for many years.

 

I'm fairly sure the 400 and 460 share the same bolt pattern so it should work. Yes you could have a C4 since ford used the c4 behind the 351M (de-stroked 400) at some point in the 70's; it was a rare setup. I would bag the 400 and install a 460, just find a donor truck in the junkyard and get everything you will need. Do a search on 400 to 460 swap, this topic has been pretty well covered. Performance Automatic in Gathersburg MD specializes in C4 transmissions and has anything you need to complete your C4/460 install. Good luck and keep us posted on progress.

 

A couple of years ago, I saw a swap kit to put a C4 behind the 460. This was from a Summit or a Jegs catalog. As another posted mentioned, if the C4 was an option behind a 351M, this could be done with factory parts.
The same speed catalog also was selling the complete C4 tranny that claimed would hold up to about 1000 HP, so I guess somebody is making the C4 pretty beefy.

 

I picked up a C-4 from a late 70's T-bird with a 351M to use behind the 460 in my Mustang.The C-4 I got was the pan fill version with the 164 tooth flexplate.My C-6 flexplate is also 164 tooth as well and has the same converter pattern as a C-4.This means I can use the C-6 flexplate with the C-4 converter to keep the same balance.Comparing the C-4 flexplate to the C-6 though and you find when layed down flat the offset is different which will effect the converter to flexplate clearance.In order to solve that problem some people just use two or three blockplates to get the right clearance.