i have a 79 ford bronco with a 351m in it from a 77 f-250 and it has plenty of power for passing or getting through those deep mudholes. My only problem is gas mileage. i am getting around 6-7 mpg and i want to improve on it. i have been pricing parts to make my 351 more fuel efficient and powerful and its gonna cost around $550. a friend of mine can get me a 460 out of a 1971 lincoln for $300. he told me that i would be getting the same improvement in gas mileage with the 460 as i would if i fix the 351m, and i would be gaining a lot more horsepower also. i was wondering what all you other ford guys would do. and i was wondering if there are any other mods i might have to do to make it fit? i know the motor and tranny will bolt up but is the 3speed c6 gonna work with the 460? i wont be beating on it or anything too much.

 

seriously guys, i need some opinions here. don't just read it and not reply. the reason people post discussion topics is because they need help or other opinions. so please reply.

 

I have a hard time believing you will improve gas milage with a 460...

I only get 6-8 MPG at best...

As far as the C6 goes, I'm curious as well, I'm wanting to swap my BW T-18 for a C6 if it'll work.

$300 for a 460?? Where at, how many miles on it, is it complete?

If you don't want it let me know where it's at

 

I'm running a 79 Bronc with a 460 (EFI at that) and I'm averaging 12 mpg, C6, 3.5 gears (soon the be 4.10's)

 

im currently doing that sawp in my 78 150, you're gonna need motor mounts and headers, plus the belt set-up, check out www.broncograveyard.com i got everthing i needed there

 

If the 460 is in good shape, go for it. I never much liked small engines...

I would make sure to check how the 460 runs, any noisy lifters? burn oil? make interesting sounds? leaks? get a good radiator to cool the 460 as well.

 

It's not horsepower that you will be gaining so much as torque. The C-6 will handle the 460 just fine. The 351M uses the same bellhousing bolt pattern, so big deal there either. Motor mounts and headers are about the only concerns you need to worry about. If you have a small radiator, then change that too. What is coming with the 460? If you are getting all the brackets and accesories, that's a big plus. And yes,,, setup properly the 460 can and will get better gas mileage, depending entirely on your driving habits, of course.

 

I've had most combinations of non-EFI 429/460s in an 82 Bronco over a 17-year period. If gas mileage is your goal in a 5000+lb brick, I'd pass on the 385 engine.

Here's the latest engine:

http://www.angelfire.com/realm3/george_d/index.html

 

in response to jokerz post, yes it is complete and there are 63,000 miles on the motor. the engine is from some old lady whose husband died and she has no use for an engine lying around. it is out of a lincoln continental but i have the parts to swap it.

 

If an easy swap, go for it. YOu won't get good MPG, but at least have the power. I get 11mpg in my F250 4.10/C6.

 

Then 460 will improve your mileage, but, depending on how the motor is set up you could only see anywhere from 1-2 mpg all the way up to around 10 mpg better. The 351m/400, IMO, is one of the worst motors Ford has put in an automobile. Poor head design, poor crank/bottom end, poor power, and poor economy. I think you would find it will take a lot more than the $550 to gain a lot. If your main concern is mileage, swap motors and tranny's for a 351w, that will give you one of the best balances between power and consistant fuel economy. Plus, everything about them is cheaper (cost, not quality).

 

i read in one of fte's tech arti. thats the m heads were designed after the "boss" heads. if tis is so how are they a bad design.???

 

I have an 86 F250 4x4 3:55 gears, 460 with a C-6 and get 10-13 MPG at 65 MPH. Towing I get 8-10 MPG at 65 MPH.

 

The 351m/400 2V heads are not even close to a boss head. They are open chambered vs. the "Boss" closed chamber design. Also the ports are of a poor design, the port runner is only half the size of the opening. Now, if you could find some 4V heads you would be ok, but, you would still have the poor bottom end. If you went into the motor and fixed the oiling problem, then the bottom end would be better, but still not quite as good as the 460.

 

hhhhaaaaa! your kung fu is strong. thanks for the info