i just picked up 300 to replace 460 in my 77 250 4x4 . whats the best way to build a 6 for towing? this is being built for a co. work truck. and needs to get at least 14-19 mpg if at all possible. so which intake cam and headers would be best for this build? thanks for any info

also want to install 5spd which one is easier to install nv4500 or a ford 5 . this will also have a g/v overdrive installed in addition to 5 gear

 

Depending on your gvwt your probably not going to get that kind of mileage.

Intakes are getting a little limited. I assume that you intent to go to a 4v carb.

Cam in the 260 range will give you a good power curve.

For a work truck I'd use EFI manafolds that have been port matched instead of headers. Use a good highflow cat and 2.5" single pipe too finish the exhaust.

Unless you really want to spead the funds of the New Venture and a coversion plate, I'd search out a ZF5 with the SBF bellhousing instead.

If your going to be hauling heavy regularly, 18k+ gvwt, I'd look into a turbo diesel swap instead. You'd have power to burn and better mileage that the 460 your replacing or a 300 under the same kind of load. I've seen a few Cummins 12v's in full size Bronco's and F250's. They do cost up front though, but are nearly bullet proof if done right.

 

Id explore my options with the 460...most people get the idea the ford300 is a work horse that lasts forever, its an underpowered turd, of course it will last forever.


If your hell bent on the six banger...

higher compression ratio
little more cam than stock
long tube headers
500 cfm four barrel carb
offenhauser DP

those are pretty standard modifications and about what your limited too.

there are many camshaft suppliers, off the shelf would be the usual big names, look at crower specifically. A mellings is a cheap camshaft but would work, maybe not as efficient. A place called reeds cams can set you up with something a little more custom ~ not really that much more expensive. Your gonna want to have an idea of the compression ratio you plan to run, as well all the other modifications, all the way down to tranny, before you start talking cams with reeds though.



If your looking for hard numbers about the only thing your gonna find is col. flashmans buildup. Do a search, It will give you a parts list, youll have to guess what the builders idea of port/polish meant but there is dyno results. Most modifications done are standard, except the slight stroke increase thats not mentioned but if you crunch the CI numbers based on bore, it musta been done.

 

If you are looking for 14-19 mpg the 460 is not an option. I think you are on the right track but if you plan on pulling any thing too heavy I think you shouldn't be so concerned with mileage. I love the 300 but it isn't the worlds most powerful engine, mine pulls a small boat (about 3000-4000) pretty good, but a my car on a trailer (5000lbs) is a little much and mine is EFI but my carbed motor in my 82 seemed about the same.
-Johnboy

 

The 300 is a good motor, IF you have the right driveline to back it up. The power curve is in all the right places for towing... However, unless you have some nice low gears, it's quite underpowered for anything truly heavy.

It hasn't been mentioned, but have you looked into the 400M? I know it was ford's attempt to replace the 460 for gas mileage and emissions reasons. Perhaps it can serve the same purpose for you.

 

i only do light towing 4500 lbs max. and with nv4500 5spd and gearvendors i should have enough gears to keep it in its sweet spot.
ordering offy dp intake , best headers to buy? and best cam.? 4barrel carb./
also who has best prices on these parts?

 

Headers, go with long tubes...most choose hedman

Best cam for towing/street use...any 260...crane offers one advertised as a truck powermax camshaft...crower would be another good place to look, they have even smaller grinds. Problem is, most members have tried at least one brand/grind but collectivley, there is no way to determine which was more ideal. The crane and crower seem to be more updated, the rest have remained the same for years and years....this may translate to a small percentage difference in reality but its all you can really go on.

Most go with the holley 390cfm...based on a common CFM street formula, and thinking 3000rpm would be your max rpm, on paper that would be more than enough cfm.

jegs and summit usually have what you need.