401 vs 432 torque ratings???
 

Chart has 432 rated at 336 lb-ft @2000 rpm and the 401 at 348 @ 1600.

Why does smaller engine with shorter stroke have more torque?

Is the 432 a Magnum????

I have a 401 but have a serious craving for TORQUE!!!!

Edit to add Wikipedia quote:
"In 1973 & 1974 there was also a 432.2-cubic-inch (7.1 L) version with enlarged crankshaft journals (4.875 in × 3.86 in (123.8 mm × 98.0 mm) bore and stroke). The 432 was a 401 with a 478 crankshaft. It produced 190 hp (142 kW) net at 3200 RPM and 336 lb⋅ft (456 N⋅m) net torque at 2000 RPM. The 432 was a Magnum engine though it was never designated as such."

Re: 401 vs 432 torque ratings???
 

I find that a little strange as my '62 478 had tons of Torque. It was like an old Mack. Even my 305 had some Torque for what it was in my '62 4000.

Re: 401 vs 432 torque ratings???
 

Make sure you are comparing like figures. The 401 being older ws usually rated in gross figures, the 432 in net. The change happened around 1971. Net is usually 15-20% lower. Also, the 432 was tuned a little more for emissions, such as the standards were for heavy trucks in the early 70's. Nowhere near as stringent as passenger cars at the time, but still a factor. Yes, the 432 had Magnum heads, manifolds, and carb..

Re: 401 vs 432 torque ratings???
 

Looked it up, in 1972 the 401 was rated at 298 ft. lbs. at 1600 r.p.m. net.

Re: 401 vs 432 torque ratings???
 

From the 6066GMCguy page
432 401 If the rating system changed what would be a good estimate of what the real numbers are?

Bottom line question: Does 432 make appreciable more torque than 401?

Enough to be worth the difficulty in finding one?

Re: 401 vs 432 torque ratings???
 

The 432 seems to be pretty rare. You never even hear of them anymore.

If you would like to have a lot of Torque, why not go to a 478. They are around here and there.

Re: 401 vs 432 torque ratings???
 

I would think it would be REALLY hard to notice 12 #/ft of torque in a truck engine, especially when the higher torque is at 2000 rpm and the lower torque was at 1400 rpm.

I agree, if you want MORE POWER, drop a 478 in the truck. More HP and torque. NO replacement for displacement!

I got invited to join a Facebook group dedicated to Ford's new 7.3L gasoline V8 engine, 444 cid, I forget what the HP & torque numbers are, well over 400, more like 450 each. That engine is taking a BIG BITE out of diesel engine sales.

Re: 401 vs 432 torque ratings???
 

That Ford 7.3L gas is generating a lot of interest. Seems to have good power, but I have seen the insides of it and can't say I am super impressed with it. I have heard rumors that GM is working on a new V-8 even larger than their new 6.6L. Maybe GM ought to design a modern version of the old V-6!

Re: 401 vs 432 torque ratings???
 

Bob - The 7.3 was recalled, stop production order put on it for a couple weeks after only maybe 1000 engines were built. There's a tubular oil manifold used to oil the underside of the pistons sorta like the squirters on diesel engines, and they were formed incorrectly and were hitting the conn rods, made an odd noise and and there were chances the manifolds could break and foul up the rods and crankshaft.
Some guys are looking for wrecked 2020 trucks to get a 7.3 to shoehorn into their Mustang GT's. The 5.0L makes 460 hp, not sure how much of an improvement the 7.3 would be.
I was hoping the 7.3 would be more of a newer modern Super-Duty like the 401, 477, & 534 CID V8's Ford made back in the late 50's, 60's and I think early 70's. Back when GMC was building these great V-6's. GMC built in so many little features into the V6's that made them hold up to hours and hours of wide open throttle and fire up the next morning and do it all over again. The 637 cid V8 that replaced the 702 V12 is the largest displacement V8 built by ANY GM division, if GMC wants to offer a BIG modern gasoline engine I think there is a market for it. Lots of companies have a hard time justifying a medium duty truck, and a high priced diesel engine with higher priced maintenance needs makes that much harder. Company I worked for put about 50,000 miles a year on their 24 ft box truck. It was a Navistar with DT-466E, it was replaced with a little Sprinter van, also a diesel. But that was after ultra low sulfur fuel but WAY before DEF. SON's 2014 Ram 2500 kept setting Contaminated DEF codes, His Dealer kept complaining he wasn't using MOPAR DEF, he used Peak, ALL DEF is made at the same plant in Iowa, anyway, This dealer happens to be in Iowa. It cost $1500 but the truck was deleted, no longer used DEF at all. I can't imagine a contractor going through that kind of run-around, he would just buy a gas truck.

Re: 401 vs 432 torque ratings???
 

I don't know a whole lot about DEF engines, but I believe it would be enough for me to go with a Gas engine.

If they ever brought back the 637 V-8 Gas, they would really need to work on the Fuel Mileage. I never did check it personally, but I believe the '71 637 that I drove only got about 5 to 7 all around. Although many times I would be maxed out at the full 46,000.

Re: 401 vs 432 torque ratings???
 

BILL - I haven't had a DEF diesel but I drove a '96 F250 with 7.3L PSD for 23-24 years, and 304,000 miles. I gave it to my Son, he traded his Cummins for his mid-life crisis, a new '18 Mustang GT. He fixed a lot of things that needed done to that truck, and it's completely reliable again, at 315,000 miles.
But I bought a gasoline pickup. Hard to justify a diesel when I only drive 2500-3000 miles a year now.
I'm surprised your 637 V-8 got 5-7 mpg. I drove a late '70's IH FleetStar single axle tractor 478 V8 and straight 5 spd, ran 62-65 mph between the Mississippi River and Des Moines 5 nights a week and got between 3-4 mpg grossing about that same 45,000-50,000. 13--1/2 ft tall 45 ft trailer caught a LOT of wind. The '81 or '82 F700 Ford tractor I drove for 6 months before the FleetStar had a 8.2L Detroit Fuel Pincher diesel, I got an honest 7-8 mpg pulling the exact same trailer hauling the exact same loads. But every couple months it needed a tune-up, troublesome fuel system. Drove a single axle dump truck two summers in college, C65 Chevy's with 366 V8 and 5+2. I really can't say what they got for mpg, no gallon counter on the gas barrel at work, but if I ran hard enough hauling rock out of the quarry I had to put some gas in for the last load. I was the only hired help summer of '74, I put a LOT of miles on a brand new C65 that summer. It had much better rear gears for road work than the '67 C65 366, 5+2 did it replaced, but the '67 spanked the '74 bad plowing snow.
The thing I see guys have the most problem with on old gas powered trucks is keeping the brakes working reliably. Second biggest problem seems to be finding rebuilt carbs and fuel pumps.
When I was a kid Dad drove for a couple livestock haulers, think they all had GMC Big V6 powered trucks. Livestock hauling was the last segment of trucking to start using diesel tractors. Lots of old farmers thought the diesel exhaust hurt their livestock, tainted the meat just before butchering.

Re: 401 vs 432 torque ratings???
 

The renewed interest in gasoline engines for medium trucks is due to the high purchase cost and maintenance/repair expenses of the new DPF/SCR diesels, The overall ownership costs for diesels are higher than gasoline engines in many situations, particularly low mileage/speed operations that utilities and municipalities experience. This trend has been a long time coming, in fact GM was trying to capitalize on it back in 2008 when they were the only manufacturer of gasoline powered medium trucks. When GM dropped their medium trucks in 2009 it left a hole in the market that Ford was able to exploit in 2011 when they began offering their 6.8L V-10 in the F-650.

Re: 401 vs 432 torque ratings???
 

Both my trucks had Air Brakes, the '62 6500 and, of course, the '71 9500. Only, I found out somewhat after I quit driving it that the '62 only had Rear Brakes!!

Still had no trouble stopping and don't remember the mechanic changing the Brakes that often.

The 9500 with Full Air had the well liked Maxi Brake (Spring Brakes). The old Dashboard E-Brake in the 6500 didn't hold very well. Had to cut the truck off and put it in gear many times to help it.

Parking on a hill with a full load grossing out at 32,000 was pretty impossible, lol. There is nothing like a Maxi Brake.

Re: 401 vs 432 torque ratings???
 

I was excited about the new Ford 7.3L when I first heard about it and have been following it closely. It is the first gasoline engine designed primarily for commercial trucks in many many years and it's output figures are good all things considered. Have to say after seeing the 7.3L in person and having a good look at its internals I am not that impressed. It seems to borrow a lot from the GM LS engines, which is good, but other features look questionable. For instance, one of the features of the GMC V-6 was its wide cylinder bore centers. This allowed bores up to 5.125" (478) and still have plenty of water passage between the cylinders. It also provided for wider crank bearings and a lot of block deck surface for a good head gasket seal. The Ford 7.3L has a siamesed bore block and one of the thinnest deck areas between cylinders I have ever seen. In addition, Ford saw cut a cooling passage between the cylinders open to the deck, further compromising the head gasket sealing surface. The block coolant passages are largely open to the deck. I guess with current head gasket technology this will not be a problem in service but I suspect this block might be 'throw-away' come rebuild time and you probably shouldn't consider super- or turbo- charging it with any meaningful boost. No roller timing chain, the 7.3L gets by with old style silent chain and a plastic tensioner, and also has a small separate chain and sprocket driving a shaft turning a rear mount variable displacement oil pump that is actually part of a large aluminum cast windage tray. Really kind of clever but a lot of extra parts. Engine has variable cam timing, but it appears all VVT components are behind the timing cover, not accessible behind the water pump like an LS. Cylinder heads look pretty good port and valve angle wise, but do not appear to have much coolant flow through them. The head bolts are large and threaded deep into the block, but the block casting looks to be very light. The whole engine is only slightly larger than an LS. Overall, I might consider a 7.3L in a Super Duty pickup but I think I like the new GM L8T 6.6L direct injection gas V-8 better. It makes a little less power but I hear the fuel economy is better and you just can't beat an LS/LT for toughness and long life.

Re: 401 vs 432 torque ratings???
 

The surface to volume ratio of the old V6's wouldn't work with todays emissions requirements. In addition, that's why the V6's were so hard on fuel.

By the time the engineers dealt with that, the only similarities would be that they are V6's.