460 to 351 swap in a 78 F250
#1
460 to 351 swap in a 78 F250
I have a 78 F250 sitting in my back yard that needs some work to get her on the road. The 460 was just rebuilt before it went to the back yard to sit. Been thinking about getting her road worthy again but with the gas prices they way they are was thinking about down sizing to a 351 wich will still have power but also better gas mileage? My question is will the 351 bolt up to the C-6 trans already in the truck or is it a different bellhousing size or bolt pattern for the 460? Also what kind of motor mount mod's will have to be done? Any help will be appreciated.
Thanks
Mason
Thanks
Mason
#2
Yes the 351M will bolt up to the trans.
It may require a different flexplate and or T/C though.
IMO, The 351M is a boat anchor.
It uses more gasoline to equal try to the power of a stronger engine
So much for fuel savings !
Put a 400 in instead and get the best of both worlds.
Retro fitting ?
Just Look at any of the 400 to 460 swaps threads and you do the opposite for what they list
Engine mounts are different.
You need a donor truck
It may require a different flexplate and or T/C though.
IMO, The 351M is a boat anchor.
It uses more gasoline to equal try to the power of a stronger engine
So much for fuel savings !
Put a 400 in instead and get the best of both worlds.
Retro fitting ?
Just Look at any of the 400 to 460 swaps threads and you do the opposite for what they list
Engine mounts are different.
You need a donor truck
#4
Masson,
I can’t say that what happened to me is the norm but here is my story.
I bought my 78 4X4 new with a 400 c-6 auto and 350 gears. After the bottom went out at 130,000 mi I rebuilt it stock and put another 230,000 mi on that one. Neither 400 engine ever got more than 12 MPG combined driving. I’m heavy on maintenance, kept them tuned and stock but for the gas they took they both pinged under load when warm and had a habit of running hotter than I liked. Two years ago I replaced the second one with a 460 that I built with a mild cam added a 4 brl carb and Edelbrock manifold. If I drive it normally I get 12MPG (same as both 400s) ………….. BUT………. if I want to tow or just get on the freeway quick, the 460 has all the poop to “get ‘er done”.
I know there are a lot of guys that like the 400 but after half a million miles looking over the hood of my truck there is no reason for me to even think about going back to the 400 and the 351, from what Iv herd, is worse.
Well that’s just my opinion based on some experience……….for what its worth.
However, if you do go ahead, the swap is not tough. A donor is a good idea. There are a few "bolt on" differiances between two wheel and 4 wheel drive engines and in addition you need to swap motor mounts, towers and exhaust. Fan shroud, alt and PS may need attention.
I can’t say that what happened to me is the norm but here is my story.
I bought my 78 4X4 new with a 400 c-6 auto and 350 gears. After the bottom went out at 130,000 mi I rebuilt it stock and put another 230,000 mi on that one. Neither 400 engine ever got more than 12 MPG combined driving. I’m heavy on maintenance, kept them tuned and stock but for the gas they took they both pinged under load when warm and had a habit of running hotter than I liked. Two years ago I replaced the second one with a 460 that I built with a mild cam added a 4 brl carb and Edelbrock manifold. If I drive it normally I get 12MPG (same as both 400s) ………….. BUT………. if I want to tow or just get on the freeway quick, the 460 has all the poop to “get ‘er done”.
I know there are a lot of guys that like the 400 but after half a million miles looking over the hood of my truck there is no reason for me to even think about going back to the 400 and the 351, from what Iv herd, is worse.
Well that’s just my opinion based on some experience……….for what its worth.
However, if you do go ahead, the swap is not tough. A donor is a good idea. There are a few "bolt on" differiances between two wheel and 4 wheel drive engines and in addition you need to swap motor mounts, towers and exhaust. Fan shroud, alt and PS may need attention.
#5
#6
If that 460 was just rebuilt why change it. I guarantee you a 351 will not get better mileage then a 460 an with the motor already rebuilt an in there an should be a no brainer. The 460 is a torque monster an will pull anything you want with it. Why ruin a good thing. Was this 250 a 4wd or 2wd. I dont think Ford put a 460 in the 250s 4x4s. Not until 1982. Good Luck an keep the 460 in there if its in good running order.
#7
78 is a 2 w/d, Ranger XLT, Camper Special. May be the carb but before it was parked the truck was only getting maybe at the most 8 mpg! I do know people w/351's saying that they getting anywhere from 12-15 mpg? I would like to get 12 mpg w/the 460 but dont think that it's possible? ( I'm not the best mechanic to say I can or can't) I do know that the truck is only with in a grand or so to get it on the road the way it sits now, and here in So. Cal. gas being close to $3.50 a gal. 8 mpg aint gunna cut it!
Trending Topics
#8
rebuild or buy a new carb and try it out. a holley 750 vacuum secondaries would be about perfect IMO.. sounds like you'll need a new on e for a different motor anyway so give it a shot before you're into it the cost of a donor truck, motor, rebuild kit, etc.. by the time you figure the cost of all the other things you need for 351 you're probably looking at a grand... easy!!! so if a new carb gets you to 10 or 11 you only lose 1-2 MPG, which you'll make back up anytime you tow something.. even in So. Cal. you can buy alot of gas for $1000. at 3 bucks a gallon, its 333 gallons you can afford to dump into a 460 before you reach the price of a motor swap. $0.02
#9
The "grand" I need to put in to it is for all new brake system, new bushings on front end and anything that needs to be replaced on the frront end. And a new steering box. I was hoping that an Edlebrock intake and 600 Cfm carb w/headers would get me atleast 12 mpg w/the 460. Is it possible?
#10
Mason, When I wrote my first reply I was on my way out and ran out of time.
Please let me share something with you as it deal with what Craig mentions.
Please read Post #17 on this thread.
https://www.ford-trucks.com/forums/s...d.php?t=102632.
Please let me share something with you as it deal with what Craig mentions.
Please read Post #17 on this thread.
https://www.ford-trucks.com/forums/s...d.php?t=102632.
#11
It is all in the gearing. There are only 3 decent truck engines as far as I am concerned, -the 300-6, 400, and 460. As far as the 400 if your 400 is pinging the EGR and distributor is not set right. Both the 400 and 460 benefit from a straight up timing chain setup. Before I parked my 78F250 with a 400 I was getting 12 MPG and that engine was VERY sick. A properly setup 400 can get 16MPG or better. I can do the same with a 300-6. The 460 is difficult to gear high enough to get great gas mileage but it can be done with sub 3.00 diff gears.
Thread
Thread Starter
Forum
Replies
Last Post
foxbody429
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
11
01-22-2013 10:08 AM