Interesting comparison

I've spent this last week filling terrace washouts and things I should have done for years. I lined up the grain trucks - a 58 GMC and the 74 Ford. The Jimmy has 77K miles and the original 270 six. The Ford has 20K miles and the 330 V8 (and a two foot longer box). I filled them both just past the helper springs and then dumped both, etc.

That old Jimmy outperformed the new truck every time. When driving through the fields she had the torque to run in two high. The Ford was lucky to be in second low, but often needed one high. The Ford hauls more but I thought that engine would have more guts. If it got below 2000 rpm it fell flat and quick. Actually stalled it a couple of times in the soft spots. It is definitely missing the low end torque of a six. The GMC could lug down to 1000 rpm and pull right back out of it.

I did finally have a chance to compare them using my speedometer app. In the high range they have exactly the same gearing. Low range the same I would guess, but I didn't check. I guess it would have been better to get a six than the smallest V8!

The old inline 6 has a lot more torque at low end RPM than the V8.

I drove a school bus many years ago, I was just out of high school.
It was about the size of a regular bobtail truck.
Chevrolet with a six cylinder engine and four speed truck transmission.
On muddy roads it was a chore to keep it out of the ditches.
One very wet occasion my bus was in for maintenance and they gave me a substitute.
It was almost twice as long. I was concerned about the muddy roads.
I had absolutely no trouble on those roads. I kept it in the middle with ease.
Guess the extra weight helped me.

yes a six cyl. engine will lug through heavy pulling. while the v8 will just stall once the rpm get too slow. i used to have couple cockshutt 542 combines. one had the 265 flathead chrysler engine and the other one had the 318 crysler engine. when they would pickup a clump of tough straw the 318 would just stall. that meant the cyl. was plugged so time to unplug cyl along with some chinese words. the 265 would slow down till you figured it would stall then just split it out and rev up again and keep going.
even the old 292 chev six cyl. was a great powerful lugging engine. that would be an engine to put in a tractor, if you could afford the gas.

Exactly one of the main reasons the old 2 cyl John Deeres had the following they had. Same cu. in. and same rated hp as a competitors 4 cyl and even 6 cyl but put them in the field instead of a dyno and no comparison. Wasn't until all the 6,s went to auto shift , torque amp , over-under etc, that finally let the revvers show their stuff. Everything was rated at "max hp" and "max torque" at the rpm at which it happened. Never took into account what happens when lugged down 500 rpm (or 25%). Lug a 4010 down 25% and see what happens. Now lug a 830 or 730 JD down 25% and it just loves it. A Ford 302 v8 will make upwards of 300 hp but that's rated at 6000 rpm and a Ford 300 six (taxi and truck app) at most 175 hp at 4000 rpm but the torque is almost equal but the 6 makes way more at 2000-3000 than the v8 does. Revvers belong on the race track and let the torquers do the work.

The tendency among V8's it to have a large bore/short stroke, which will make it pick up revs much faster. 6's tend to be long stroke, compared to bore- slower to rev, but much more torque at low RPMs. Takes a pretty long, steep hill to make me shift down in my Hudson.

Most of the bigger trucks I've driven with the BIG 6 have always performed
well in off road a Place where Low end torque was needed. Whether is was a
300 six in a F600 or the chevy big 6. Most of the 6's had a tad shorter ratio
in the rear that really helped. Power band on a V8 requires few more RMPs.
But if you were pounding them over the highway long distance that shorter gear
wouldn't have been to your taste unless you lived in the mountains..

Longer stroke working for ya'. Also the Ford is into the early smog years. 4" stroke on the 270 vs. 3.5" stroke on the 330. The port size and velocity are probably better optimized on the GMC for low RPM.

Just as others stated below-6 cylinders will lug and pull better.All your class 8 trucks(semis)run 6 cylinder engines.Most all large tractor engines are 6 cylinder,too.Mark

It's interesting to play with the numbers. Take two engines with 50 cubic inches per cylinder, one with a 4.0" bore, 4.0" stroke and the other with a 3.5" bore, 5.2" stroke. If you calculate the theoretical torque that the piston can apply to the crankshaft for a given cylinder pressure you'll find that it is exactly the same for both engines. (The increased "leverage" of the longer stroke is countered by the greater "push" of the larger piston's area.) The typically better low end power characteristics of the small bore, long stroke engine are due to the fact that low speeds is the only place this engine can operate due to the resulting small valves and piston speed limits and it is therefore tuned accordingly. It only makes sense for a manufacturer to tune the larger bore, shorter stroke engine to take advantage of the better breathing capabilities and higher speed potential in order to provide more power. The cam profile and timing that provides this often comes at the expense of low rpm torque but since power, not torque, is what determines how much work an engine can do in a given amount of time it is a worthy trade-off. Which is better or worse all depends on what you're doing and what you prioritize most.

That old Jimmy outperformed the new truck every time.

Click to expand...

I guess that's an indication of the age of some of us when a'74 is considered new. LOL

well the gm has shorter stroke too ,,.I can concur about your findings ,,, I have 58 chevy Viking , original 283 v-8,,and a 75 ford with a 330, I haul grain with both .. and to be honest I would rather haul a load with the old 58 Viking , could be because my great uncle bought it new , but ,, It is always eager to tackle the next hill with zest ,, while the 330 ford ,just whined and roared groaned and used gas . could a been a bad carb ,,the 330 motor cog- lokt a rod nd became a memory ,, it was replaced by a 391 ,a new carburetor , that ford was ready to go hunting for that chevy now..,.. btw ,, the 283 will get 8 miles to the gallon round trip .. the ford is lucky to do 7mpg even with the new 391