I have a 1970 F250 with a 360 factory motor and a Warner T-18 transmission all original and still on the road.

I am pondering swapping out the 360 with a 351m; but discovered I would need a flywheel, clutch, starter, and bellhousing to complete the conversion; did I miss anything?

I have also read the 351m is not a good motor compared to the low end 360; 351m has better performance and mileage, less torque and longevity.
That being said, I have read that building my 360 up to a 390 would be a better way to go.

I was informed by a local head shop that to convert my 360 to a 390, I would need the 390 crank, pistons, rods, and HEADS...

Would I need to replace my heads or just rebiuld tham?

Any advice would be appreciated.
Mejamz

 

Forget the 351m. Too many things to change, and the 351m is seriously lacking in power in stock form, so you'd be looking at a rebuild and work there too.

You can rebuild the 360 or make it a 390.

A 390 uses a different crank and rods. 360 pistons can be used in the 390 for a CR in the 9s. Other piston options are available for the 390.

If your heads are good, the will work fine with a 390.

Do you have a budget in mind? Do you want more power, or just a freshened engine?

 

This truck is a good work truck with a nice granny. The engine is original. My truck is used in high altitude constantly. It is used mainly for pulling and hauling. 1970 F250, 360, Warner T-18, so in reality, across town driving uses only three gears, 2nd - 4th. I would like to get the best possible performance and reliability for a modest price.
As it stands, I have a rod knock and the rear main leaks; however, I have replaced the timing chain to extend life as much as possible. The engine, wiring, and cosmetics are all thats left to do.

 

It will cost less to turn it into a 390 than it will to swap to a 351m. Like he said you only need a 390 crank and rods. I would be looking for a different builder if he doesnt know that all FE heads are interchangeable (except 427). I'm sure he's good and all but it sounds like he doesnt have experience with FE's.
390 will give you better performance and mpg than 360 or 351m.

While you're rebuilding I would HIGHLY suggest doing the oiling mods found herehttp://www.clubfte.com/users/ratsmoker/oilmods.html

 

I voted to go to a 390 - much better torque than the 360, and no major changes to everything else.

Plus, the 351m in stock form is a gutless slug. I know, many like them, they have their fans, and if you don't go completely stock, they can be built up to do anything, including going to a 400 with a crank (I think).

But then, you'd still have to replace a whole bunch of other stuff just to get that 351m to bolt-in. 360->390 definitely.

 

I agree...go with the 390. Heck, I would even rebuild it to a 360 at the minimum then going with the 351M. You have everything you need for a 390 FE rebuild...why not use them? You'll be much happier you did.

OJ

 

I'd go 360 with a modern cam for MPGS.

390 if you just want more power.

351M while it can be a good motor with Edel heads will not be worth the effort in a swap. It has practically the same bore stroke as a 360 so its mpg gains likely came from different factory gearing.

 

Rebuild the 360... 351 will cost too much once your buy all the accesorries.
The 360 given a streetable cam will be withing 30lbs torque of the 390
and withing 20 HP....and a little better economy

 

I'm doing that now, if the block checks out. going in a
Fairlane though. Bought it as a 390GT clone, but chasing a vibration had me discover it is really just a truck 360. I'm going to keep my pistons and find a 390 crank and rods as others have suggested.

Here are the numbers I found on another site that back this up:
FE block deck height: 10.17"

390 crank throw: 1.89"
short(390) rod length: 6.488"
360 piston compression height: 1.776" added together: 10.1540

 

Take a look at this thread page 3 https://www.ford-trucks.com/forums/1...-makeover.html

It has the measurements and math you are looking for for deck clearance, and static CR.

 

Beautiful!
Maybe I klept that info from you! Are you also fordification? ;-)

 

Not a member there but I do reference things there some times as well as the fordfe site.

 

Will A 360 engine with a manual tranny fit up to a 390? Need to know if I'm going to have trouble with the bellhousing. Need a new transmission for my 390 and have found one that is attached to a 360

 

Identical. 360 is a 390 with a 352 crank, so externally, they are the same.

 

Caught ya slipping. lol