Hi folks,
I've got 2 trucks:
1st is an '86 F350 crew cab long box dually. Gas 460, 4 bbl, 5 speed, 410 diff, 2 wheel drive.
2nd is an '86 F250 extended cab 4 wheel drive. Propane 460, zf-5 tranny, 355's. It pulls 27,000 lbs total weight (truck, trailer, load) with ease.

The F350 is retired & is being restored. It will get used for heavy loads periodically, just cuz it's my favorite truck & it's fun to drive. The F250 is my long distance driver unit - it's covered 1,000 miles in a day's driving & we'd trust it anywhere.

Question: I want to maximize the torque & HP on both trucks. Im willing to do anything on these engines to reach that goal. Can anyone offer suggestions? I want to stay with the 460 engines, so Cummins ain't invited to this party.

 

New cam headers duel exhaust 429 heads if can find them

 

Mine is a 400, but it is expected to easily put out 500/500. So it should be easy to do that with the 460. Keys to mine are Trick Flow heads, 10.5:1 CR, custom ground Comp full-roller cam & Scorpion lifters, and headers.

 

Stay away from small chamber heads on the gas engine.
Later engines used the same heads for 4V applications, whether 7 or 7.5 litre.
Poor quench and pump gas do not work together.

Torque and horsepower begin at opposite ends of the rpm range.
YOU need to decide on a redline and power goals before you start.

A crewcab dually could probably use all the displacement it could get.
You say it is a 5-speed. Is that a ZF as well???
420 and even 470 ft lb limits are going to be easily exceeded.
Look into beefing up the ZF or at least going through it.
Traction will be the limiting factor if empty.

A) There is no replacement for displacement.
A Scat or Ohio crank 521 kit with .030 bore will drop in.
Get rid of the Thermactor humps and do some porting + oversized valves if you choose to keep the iron heads.
Zero deck the block.
Choose a 750 cfm or greater vacuum secondary carb and an intake appropriate for your redline.
Cam to suit.
Headers, though not necessarily longtubes for such a vehicle.

Scott Johnston at Reincarnation High Performance is an acknowledged leader in 385 series engine development.
There are others, but he freely shares real numbers on the forums...
He has packages with heads, custom ground cams, valvetrain and rotating assemblies.
Re in"Car"nation High Performance - Home

B) The propane engine is more a quandary to me.
I know the high effective octane means much higher compression ratios (12:1 or more) and limited ignition advance are needed.
I don't know anything about cams optimized for propane.
I imagine you are going to need to beef up the clutch with that much trailer weight.
Go to a powertrain specialist and forget about 'race' clutches like Centerforce.

Just my opinions.

 

I have a 1972 Lincoln 460 in my bronco. It has been bored to 475, it has a Comp cam, Edelbrock intake, 750 cfm carb, head work was done, and long tube stainless headers. It's pushing 500 hp. It had a 830 cfm carb at one point, and made a lot more power, but the mileage dropped to 3 mpg.

 

Nice!

Power takes fuel.
Anyone who thinks they can have 500Ci/500Hp and double digit fuel mileage is out of their mind.

 

I did a search on "460 aluminum heads" and got a lot of hits and choices. I didn't know they made so many different ones. That's where I would start for more power.

 

A lot depends on what "Massive" means...
Non-emissions D6 iron castings can support 700Hp.

500 hp is still well over 200% of stock 220ish horsepower.
This is not difficult without going to aluminum.

Trick Flow Specialties for the win on the street.
ProComp can be made to work but they need a lot out of the box.
Kasse at the top end.
And of course Ford Racing has the C460's + two pro stock SCJ heads.