Slick 60's

ok here goes.
I need to be able to pull a 9000 lb 5th wheel with my truck anywhere in the us.

300 6cyl
carbby head
oversized valves
mild porting
roller rockers
four barrel intake and carb
efi manifolds
custom 2 into 1 exhaust
magnaflow muffler

hypereutectic pistons
zero the deck
252 or 260 cam not sure which would be best.
8.9 to 1 compression or there abouts

almost forgot np435 trans. the head is finished all I need is to have the block built.

the truck currently has 3.73 gears and 19.5 tires. 300 efi 6 with four barrel intake with a carb from a 292 and efi manifolds.
I can pull the trailer on flat ground but the smallest hill drags it down pretty quick.will the added hp from the mods take care of the problem or will I have to regear?

if I cain't pull the trailer at 55 to 65 with this combo I will just buy a diesel f350 and be done with it and save the mods for later. but I sure would like to take my ole slick on a long trip around the us.

sorry its so long winded but need all the facts out there.

thanks robert

If you want to be able to stay at 65, even on the hills with the trailer loaded, I think you had better get the diesel. Although I love the 300 6, it still cannot pull a heavy load like a diesel.

everything I hear about the clifford performance upgrade, tells me you should have little to no problem. I do not know if anyone here has done that mod or not. I think if you do not get your answers here, you should ask the same question over at ford 6 performance.
If you already have the parts go for it and if it bogs alittle try the 3.89 gears

Robert nice truck and setup 300 engine. I would go with 3:00 to 3:25 gear with np435 trans. It will cut the RPM's and helpthe 300 pull at 2400. I will call you if Tom does not buy 4-barrel setup. I go with 252 cam. Tony I buy a diesel for 9000lbs 5th wheels. better brakes,frame stronger,power steering.

Much as I would like to see the ol' 350 put to that use, I tend to agree with Chris and others. The mods you are listing tend to move the torque curve toward higher rpm's.
Low end torque will consequently suffer especially with the large diameter 19.5's.
I no longer remember the gcwr rating for the single axle 350's, but I would think 9000 plus truck load would be exceeding that rating.
It no doubt can be done but I suspect the money spent might be palatable in the long run when spent on the diesel.
I have run stock 300's in single wheel wreckers, and can't say I would recommend them for long distance highway use with that load.
The mods you are considering work great in lighter vehicles. As suggested, you might look at the dyno reports on such set ups to determine if they yield a workable combination for your application.
I sure do like the idea, though!
Paul

Don't change your rear end ratio.
You will lose to much low end pulling ability.
The 300 has lots of low end torque as is.
Use your money to add gears ( 5-speed main and auxiliary transmission) and you can keep the 300 in it's stock torque curve.
I have a 250 with a 300 stock (still has points) , 4-speed transmission and 4.10 rear end.
It will run 70 on the interstate all day at 3200 rpm's.
I pull and haul whatever I want.
I have a Watson auxiliary that I am going to install.
It will give me an overdrive for better cruising rpm's as well as a under drive if I need it.
If you are going to pull a 9000 lb trailer I hope you have converted to a dual master cylinder.

thanks for all the replies.

with the engine mods listed hopefully I should get above 225 hp and 350 ftlbs. torque.
with the 252 cam torque starts at 600 rpm and peaks at 2000. the 260 starts at 1000 and peaks at 2000.
373 gears rpm is 2100 at 55 mph and 2500 at 65 with 19.5 tires
411 would be 2300 at 55 and 2700 at 65.
456 would be 2500 at 55 and 3000 at 65. don't like to turn engine up that high though. I know it won't hurt but just don't like the sound of the engine
gvw is 9800 lbs don't know what gcvw would be.
brakes would be changed to power dual master cyl.
if I can get a pattern from bill w for the disc plate he made for his f250 will look into disc brakes on the front.
for those that haven't read my build thread, I changed out the 6 lug axels for 8 lug.
1984 dana 70 8 lug and 1973 p400 front 8 lug.
the only 5 spd that would be a direct bolt in would be a clark 5 spd od and not only are they scarce but some parts are not available. from what I've read.
would love to have a brownie or watson 3 spd aux but they are just as scarce.

I've been driving truck for a living since I was 18. Mostly, I haul 80,000 lbs combined over Mt. Hood to Central Oregon and back. My current tractor puts 1950 ft/lbs to the ground at 1900 rpm. It's a 14L Detroit rated at 550 hp with a mildly modified pump and at 1900 rpm, I'm running 40 pounds of boost and I've got 13 speeds to choose from. That means I can run grades approaching 10% at 55 mph if I really lay into it and keep my momentum up.

As far as tractors go, my truck is near the higher end of what you'll find on the highways. That said, I've hauled all the way up to 105,500 with far less power. Back in the day, I pulled 96,000 doubles loaded with hay with a 300 Cummins and 20 gears.

My point is simple: Gear down, slow down. Use the tranny, not the motor. Even in my current tractor, I keep the rpm constant and rarely pull at maximum capacity. I split my high-range gears every 250 rpm and stay right in the sweet spot where power, ecocnomy, and cool temperatures combine.

While a 300 with a bunch of mods could probably do what you ask, it would live a longer and happier life with better gearing. That NP 435 is a wide-ratio transmission. Maybe consider splitting those gears by using one of Gear Vendor's products or something similar? http://www.gearvendors.com/f2wdt.html

Brown-Lipe made an over/under auxilliary box back in the 'sixties for RVs and pickups, too. They're hard to find, but incredibly robust.

As the old-timer who trained me to drive used to say, "The motor spins the gears and the gears move the freight."

And that's a solid truth. He was a wizard with a twin-stick. Give him a 220 hp Cummins and a 5 and 4, and he'd make that old truck sing.

Now that I realize we are talking about the dually, it seems more doable IMO. As mentioned ,a split gearbox would be a definite advantage, and with your compression ratio, a turbo would seem worth consideration if you found the need for more power.
Planning to get it together for Slickstock?
Paul

Check out this thread - "Will it pull?":
http://www.ford-trucks.com/forums/97618 ... -pull.html