i have a 1990 f 250. it has 351w small block, im sick of it i have a built big block 460 in the garage. i am making a mud truck, i have the motor the big lbock c6 tranny. uh the motor mounts are on the motor just sitting on the stand at the moment. i was told the t case will bolt up to that tranny.i think its the 208 tcase. 351 is efi but 460 has carb. real nice holley. high rise intake etc. basically i am asking for help on any extra needed info on this swap i am ready to pull the small block and throw in the big block i just wanna make sure i have all the parts to do it this weekend. any help will be good. thanxx

 

also i will throw in there, that last weekend i really beat on the truck. and when i drive down the road at about 25, to 40 mph the front hopes around unless i work the wheel back and forth, what would cause that? tie rod ends is my guess.also i am getting the steering shock absorber just to help it jumps pretty bad but my guess is the 38.5 super swampers dont help much but would tie rod ends be my problem?

 

U need a steering stabilizer.

 

U need a steering stabilizer, or with tires that size a heavy-duty double stabilizer. ck out summit.com

 

ok thanx i will buy one see if it helps. any info on the motor swap? or know anyone that has done it

 

Have you thought about a 393 stroker kit for your 351? Even with a mild build, you'll have a reasonably priced setup and a very strong engine. My 393 ran just as well or stronger in my f150 as my 460 does in my F350.

 

For the wheel hop check your axle u-joints. Mine is doing the same thing right now and my axle u-joints need to be replaced.

 

the thing is i already have the big block in my garage with everythign and the big block is already built a little. has 450 horse so im trying to use what i already have instead of spending more cash. and thanx i will check the u joints out

 

Welcome to the forum bbm!

You'll need 460 specific engine perches on the engine crossmember, or conversion mounts from a place like L&L or Jeff's Bronco Graveyard.

You'll also need a complete ignition system.
The DuraSpark II system came stock with carbureted 460's and is simple to wire if you have the correct coil and distributor.
Duraspark II

Then you need a way to get fuel to that carb.
Which will involve abandoning the high pressure pump on the frame rail and adding a FPR with return line to the tank(s).
6 psi is good for your Holley.

Someone will have to plumb an exhaust system for the truck. Do you have short or longtube headers on your 460?

450HP is a lot of power. Have fun but be careful.

 

i have an msd with soft touch rev control from nelson racing to power my distributor.,its a mud truck so i already have my exhaust figured out, as for the motor mounts i have the regular 460 mounts with the 3 bolts to the block and the one to the frame rail., and i already have a fuel pressure regulator but i have a mechanical fuel pump on the block so i am using that and just running a pick up tube into the tank

 

Dont forget about your suspension. your 150 came with coils and is set up for a 351, that 460 is heavy motor. if i were you id look around on some off-road forums to see whats been done as far as suspension goes........460 swaps into off-road trucks is not uncommon just do a little research.... you should be alright. btw i just did a build on 351w to 418 and LOST my efi and im loving life...........i got pictures of the build laying around in my profile somewhere.
Good Luck

 

what trans does the truck have currently. The Tcase should be a BW 1345
it bolts to a C6 just fine. thousands of trucks with that combo.

 

The perches on the frame crossmember need to be changed.
They are unique to the 460. (not smallblock, not diesel)

 

Since you are going carbed/c6 its not that hard

• L&L Motor mounts
• Reposition trans crossmember (assuming the C6 is a 4x4 trans)
• Throttle cable from a carbed F250 BB model (87 I think is what I used, available from Ford)
• F250 460 4x4 carbed header should work
• Resize the front driveshaft
• Locate the oil pressure and temp leads on the existing harness and use them to the sensors on the 460, factory gauges will work
• External tach unless you want to wrestle getting the signal to the stock tach... it can be done, but the stock is only 6000RPM and a built 460 can hit that with no problem
• Fuel pressure regulator ( I used an Areo one from summit, I can find the p/n if needed) plumbed into the supply and return lines
• Deadhead pressure regulator on the supply line to the carb. (With that setup I am running the hi-pressure tank pumps and sitting at 7psi at the Holley all day long)
• Run a constant ground wire to the ground pin on the fuel pump relay (so they will come on and stay on with the key)
• Ignition system (mallory, MSD, or Dura Spark. I ran the Mallory distributor with a Mallory box originally, now I run the Duraspark dizzy with a Mallory box) Tap the hot wire from the factory coil hot wire in the harness.

There are other various brackets and such you will also need. Belt/pulley setup, throttle cable mount, etc. You will be able to use the cruise if you're truck is equipped with it. Both fuel tanks and the switchover will still work also.