I'm getting ready to buy a 1979 ford bronco. It has the 351M, and I've heard these things didn't make too much power from the factory. I also have a 1977 460 sitting in a truck right now. I was thinking about swapping the motors out eventually, but as of now, can i swap the carbs on the two trucks and get a little bit more power? Will it choke out the motor? Another question, i know it's been brought up before, but how much trouble will it be to swap out the 351 for the 460?
Thanks,
Matt

 

if the bronc is an automatic than you will only need motor mounts to install the 460.(assuming its a truck 460, othewise you might run into exhaust manifold and front accessory troubles)

a friend of mine installed an edelbrock performer 400 manifold and a stock 460 carb on his 400 and it was like a totally diffrent motor! it ran good but probably could have used some tuning for fuel econimy etc.(smelled a little rich)

 

yeah, i'd expect it to be a little big. It's comming out of a 1977 f150, so it should drip right in. What about the wiring? would i need something different with the 79 than i would with the 77? I'm probably going to have the carb rebuilt before i put it on there, i might put smaller jets on it too.

 

The 351M would have a 2V carb and manifold. The 460 most likely has a 4V carb. You would need a 4V manifold for the 351M. There are adapters but they are absolutely worthless unless heavily modified, -even then they are junk.

 

With the 4 barrel intake the carb should work fine.As for 460s I used car accesories without much trouble when I put a 460 from a 1978 Mark V into a '79 F-100.The alternator was a low mount but worked out .The Duraspark harness plugged right in .If both are 4 wheel drive oil pans should not be much trouble. BUT HEY THIS IS THE 335 SERIES FORUM WHAT ARE YOU SAYIN MAN!!!!!Your motor will wake up with a little tuning(cam,intake & carb, timing chain).

 

lol, i know this is the wrong place to asking about swapping out the motors. I might keep the 351, but i could just rebuild the 460 and swap it in with no costs for the swap (the motor's still in the truck). I was just thinking i could get a little better gas mileage (if i keep my foot out of it) and some more power with the 4 barrel carb. I know the 460 made alot more power (didn't the 351M's only make like 150 horsepower in 1979?) and i won't have to do alot to the 460 to get alot more power.

 

the cheapest way to go if you are rebuilding an engine anyway is to sell your 460 truck and buy a 400 to re build it there are plenty of guys who have gotten 350- 400 horsepower out of thiers without too much hassle. than its just a drop in. dont get me wrong i love my 460 but my truck came with it. the 400 is a little lighter for 4x4ing and a straight bolt in swap.

 

and you won't get better mileage with a 460 over a properly built 400.

 

ok, so what kind of rebuild kit do you suggest i should do? I've heard a couple people say they are getting 14+ mpg with their 460's, never heard of anyone get too good of mileage out of their 351M's or 400's.

 

Spend some time reading a few of the posts here.

 

as for your horsepower question they made around 135 hp at the rear wheels. In 1972 the started rating them at the rear wheels so it seems low, but actually probobly made around 210-230 hp at the motor. Just estimates though. If i were you if your 351M runs good and doesn't burn oil, I would just fix it up instead. But the 460 would go in with the necessary motor mounts adn make sure that if you're putting it in a 4x4 that you have the right oil pan. wiring should be the same

 

It's in a 2WD truck right now, would i have to change oil pans in it? I haven't went and picked up the bronco yet, but i saw it start and it didn't smoke and idled good. I'm probably just going to sell the 460 like you guys have recomended and put money in the bronco. Is there a stroker kit for the 351M? or are there any aftermarket company's making 400 cranks?

 

well if u want a stroker kit all your gunna need is a 400 crank and pistons and your on your way for more power throw in some badger flat tops pistons and a cam with a aftermarket timing chain it will do u wonders

 

See my post #10 above.

 

ok, i'll check out some earlier posts and see what they say, thanks for the replies.

Matt