What I'ld do without hesitation, get a 400 crank kit and some 400 pistons .... they are available now in flat top version for more compression, or use some 351C pistons with bushed 351M/400 rods. Compression and a big kick in stroke and straight up cam timing will set you well on the path and save $$$ and time with not having bellhousing and mount hassles. Also lighter than a 429/460.

Depends on what you have to play with $$$ wise and what you want in the end?

 

I would have to agree with tbear. It's all about what you want to spend.

If you want to spend 5-10K on an engine, do it right...

If you want to go the safest and most reliable route, go with what you have (exactly what I said I was doing XXXXX posts ago...)

It's been mentioned, but the best bang for your buck is to save yourself the troubles and deal with what you have. Your engine can put out gobs of power just like any other engine that's built, but unlike everything else, you've already got the block!!

 

Lowest cost is a rebuilt from a retailer. You get 3 years unlimited mileage warranty. By the time you price in the labor in a machine shop and all the parts it is a wash, but then add in the warranty and it is easy sale for most parts guys.

Personally, if i was to keep the truck a long while, i am going 351W eventually. too many parts, options, power, etc. Better economy than going with a 460, etc.

 

Thanks for all the imput. since my post i have been reading up a little more and the 351 to 400 seems to be the best easiest change for what i need and can spend (any suggested reading or hints would be welcome, as this will be my first rebuild).

As for the rpm at speed comments, its a manual so its not missing a gear, just geared really low (which makes it all the worse to have to down shift on minor hills pulling 18' camp trailers.. ugh). It was born into this world as a warehouse/ delivery truck for a pipe company in anchorage, AK, so im assuming it was geared that way because all the roads were such that not being able to go over 50 was not an issue.

Im tentativly planning on adding one of those bolt on overdrives while i have it torn apart. once again comments are welcome on brands, pluses, minuses etc...

Last, for all of you who recommended the 460, while i don't think it will ever end up in this truck, I know its an awesome motor and it may end up in the ground up restore im planning for my families '76 hiboy sometime in the distant future.

 

With having been a delivery vehicle in alaska originally, anything is possible on the gearing. It's actually possible that regearing to a bit taller gearing could improve the towing power. Towing, particularly on longer grades, relys on the torque of an engine more than the HP, and the RPM you say it is turning is a bit higher than *most* engines peak torque RPM. Converting to a 400 will give you an engine that has a fairly low RPM for making good torque output. The 400 makes quite a bit of torque at 2000 RPM, due to the 4 x 4 bore/stroke.
To backup my statement about torque being the key to towing heavy loads, consider the engines used in semi's. They only make 400-600 HP on average, but 2000 lb/ft of torque is created, usually at about 1100 to 1400 RPM. These engines are rarely capable of exceeding 2000 RPM, yet they are capable of dragging 40 tons (80,000 LBS) up some rather long and steep grades, by relying soley upon the torque of those huge (12-16L)engines. 2.70-3.55 rear gears, and OD trans allow them to cruise the highways at 60-75 MPH, and remain well below the 2000 RPM mark.

Regearing the axle(s) could be a cheaper alternative to the bolt-on OD unit. Just food for thought.....

 

Tim Meyer has everything you need to turn it into a stout 400. TMeyer, Inc. Precision Automotive Machining
Good guy too, he'll set you up with what you need.

A new set of gears is going to be less than half the cost of a bolt on OD unit like Gearvendors. Besides, a 6.50 rear gear is useless in a street driven light truck. Maybe it works in AK but the speed limits 70mph in the lower 48.

 

Not to mention that semis get 4-8 mpg while hauling that 40 tons, not to far off a dents 8-12 lol.

 

Quite true. Dad's truck never got much better than 12, even empty. My brother's 2012 Freightliner with a 15L Detroit can get 7.5 almost any day of the week, loaded.

Dad always said there wasn't much you could do to improve the MPG on an FE. There also ain't much you do to hurt it either, so might as well make it run......
Of course, he also told everyone his truck got 17 MPG, 7 in the city, and 10 on the hyw, that makes 17 total.......

 

Pretty true. My 445ci get just about the same mpg as it did when it was 360ci. There's some guys that get around 15-18mpgs in these old trucks with V8s but they've built the whole thing for economy. Still it's not too shabby considering that newer trucks don't do much better. The shape is the limiting factor. Hard to push a brick through the air efficiently.