1981 f100
 

hello i have a 1981 f100 custom. regular cab short boxx. the truck came stock with a 255 or w.e in it, it now has a 302 and a c6 in it. i have a 460 big block to go in it. i am woundering if the motor and tranny well bolt right in, and if i have to change the drive shaft out?

you will have to end up changing just about everything under the hood. Mine originally had the 300 six and now has a 460/C6.

Just to name a few things:
motor mounts
frame mounts
radiator / shroud and hoses
transmission and associated cooling lines
drive shaft (I think)
Exhaust
fuel lines (minimal if any)
You will need to be sure the 460 has a rear sump oil pan

steering is the same

mine has the original springs and are fine

Most of the wiring is the same as long as you have the same vintage 460 with the DS II ignition.

you will need all the accessories and associated brackets (PS pump, alternator, AC, etc...)

On the 460, due to it's oil filter location, you will have to either run a remote filter kit or swap the engine cross member.

Not sure on the transmission cross member...the one you have may or may not work.

just to name a few things...I'm sure I didn't cover it all

ok thanks, i forgot that i had another thred going so i'll continue on that one, i think you responded on it too. thank you

300-6's, 255's, 302's, 351W, and 351C's all share the same transmission bolt patterns ("small block").

351M, 400, and 460's use a separate ("big block") bolt pattern.

To make the 460 fit in the F150, you'll probably need the new drive-shaft, you will need a matching transmission, motor mount perches, and motor mounts that bolt to the perches, which are what bolt to the front cross-member that support the motor. The perches are bolted, sometimes riveted to the frames of trucks and you have to go to a junkyard to get them. Motor mounts you can buy new. You'll probably also need the transmission cross-member unless you're going with a big-block C6 to replace the small-block. In which case, I think they're the same (I think, and someone will correct me as I'm 100% sure there's someone on here who has done the swap).

EDIT:

Forgot the radiator and stuff. In which case, as I was typing, Kevin is right on the money.

:)...hope I said the same thing this time as last :-huh

By way of clarification....

Aren't you referring to the engine bell housing bolt patterns?

I'm pretty sure the manual transmissions (that bolt to the bell housings) all share the same pattern. Automatics (and some manuals, e,g, the ZF5) have the bell housing cast as part of the transmission casing.

unless it's a C4, which for trucks we are not talking about. I don't know if it was all of them or not but the C4's I had, had removable bell housings just like a manual. I swapped a 351 into a mustang II that had a 4 banger in it...all I had to do was swap the bell housing. I always wondered why they didn't do that for all the automatics.

Of course that poor little C4 didn't last long against that 351...but it bolted up.

whats in the truck right now is a 302 with a c4 hooked up to it, can i just swap those bell housings out? or well that not hold a 460 pushing 500 hp. and excuse my lack of knowlegde i am only 20.

NOOOO!!! I doubt very seriously they made a bell housing for the 385 series (429/460) engines and for good reason....it would never hold up to it.

If you want to run an automatic, stick with the C6....or whatever is bolted to it right now.

And no problem with the lack of knowledge...I got lots of it

haha, k well from what i've heard alot of ppl use the c4 as a race tranny cuz there light, so i dunno. but anyways. is the zf5 a standard?

oh you can build a hell of a C4, don't get me wrong. But a stock one is a different story. My Mustang was around 500 HP (off the juice)...I went though 3 C4's until I had one built by a local guy that built race transmission. I paid plenty for it too!!!

The ZF5 was standard....later in the 80's though. Well not sure what you mean by standard actually...but it was offered. That's a big swap!!!

it was just a question. i'm talking to you in the other form too. so if you could answer in that one guys it would be great. thanks

Kevin,

The parts book shows us the C4 was used in F100s with the 6-banger engine in 1980 & 1981, Ford began using the C5 in that model from 1982 onward.

The 302 came with a C6, never a C4.

Sec A70 pp. 1-27

so well a c4 bolt up to a 302 or was i wrong on it being a c4?

yes it will...I just didn't realize they used it in the trucks. But now that Chris mentions it...I do remember the transition to the C5.

check out this page I found. It's for 70's trucks but very helpful

1973-1979 Ford Truck/Van Automatic Transmission Application Chart - FORDification.net

As expected....the C4 was not used in anything bigger then the 302. Was surprised to see it was used in the F250's though