I am restoring a 81 F150 4x4 with a 351m and 4sp trans. I would like to go with a big block motor and auto trans (more power ). Any thoughts?

Ken

 

Great idea .I wish you the best of luck with the rising gas prices though lol.In my search for parts on my 1984 F-150,I have seen headers and such for big blocks in these F-150's.Shouldn't be hard at all.

Good luck.

Nightrain

 

thanks Nightrain, it's a project for my wife and with the truck is paid for might as well go for it. the body is in good shape but motor is trash. she wants to be able to turn all 4 wheels over whenever she wants. so as you can see must be Hi-Pro. now i just need to find a motor. looking for a 429-460

 

i think the 351m and 400m are big blocks reason i say this is because back in 81 and 82 thats what engine you got when you bought a HD truck pretty sure and ive looked at posts before saying the 351m 400m 429 and the 460 all use the same block pattern point being for instance i have a 460 in my truck and i had a 4 speed in it i put a ZF 5 speed out of an 88 in it for the 5th OD gear my truck is an 84 came stock with a 460 well the ZF uses a aluminum case housing with a bellhousing intergraded into it you cant undo a bellhousing or anything is what i mean anyway ive looked on post saying that the ZF's will bolt to those engines because they are the same block pattern design so i think putting a big block in wont be a problem another thing to small block or big block you have a 4 barrel on a small block 351W and a 4 barrel on a big block 460 i bet you dont get much of a diffrence in gas milage at all reason being a small block has to rev up more to make its power where a big block dosent so it makes up for itself being a 460 its just huge so its gonna require the same amount as fuel that a 351 is gonna being it has to rev faster just my thought on that anyways plus i havent heard of any small blocks getting much better then my 460 did but with my 5 speed and being a 2wd regular cab long bed i get an average of 17 to 19 on the highway and about 12 to 16 in town thats if i keep my foot out of it around town which i usually do being it has lots of torque i dont need to rev it up to make power

 

F 2fifter, thanks for your comments. I have been under the impression for years that they are small blocks upto the 351m/400. I do know that these two the main differance is the crank and rods, and that the 390 and up were big blocks. not much experirence with ford motors other than the 292 that was in my 63 F-100 or the 302. i would go with the 302 if i thought that i could get enough HP out of it.

Ken

 

yeah i always thought they where to untill reading about them on this forum so im pretty sure there a big block engine 351m or the 400m i think a 400m is just a bored up stroked 351m block my dads 82 f250 XLT had one in it died at 100,000 miles i hear that the 400m arent that great an engine my dads didnt seem to be after dieing at 100,000 miles

 

thanks F 2

 

Big Block Fords are the 351m, 400, 429, and 460. Those are your feasible swaps as they all share the same bellhousing and fit in basically the same holes.

If you REALLY wanted to you could swap to an FE block, but this would be ALOT of work for this year of truck. This would be the 352, 360, 390, 406, 410, 427, or 428.

If youre going big go straight for the 460 swap. Straight forward and the biggest potential for power.

Justin

 

thanks justin, sorry it has taken so long to reply but i am a truck driver and only get home a couple days a week.