Propane injection

The horsepower on either your 5T or 7U can be increased dramatically by altering the settings for rack and rpm. Any change from factory settings is not advisable. The factory settings are carefully arrived at by Caterpillar engineers through years of testing and calculation. Any change from these settings risks destruction of your drive train and ultimate dependability of your tractor. No turbo or propane necessary.

I thought the drivetrain could handle it because cat put a d4600 engine on a d4 chassis and called it a d5. Not sure what modifications were done. That's why I thought it could easily handle alittle more. The fuel pumps don't seem to be really conducive to much fuel gian to really utilize a turbo.

With the right fuel injector pump camshaft and increased rack setting you can coax a little more hp out of the D4400 but with out engine balancer you are limited in rpm.

How about the 41/2" bore. Is it a 315 or something. The engine in a 7u.

The 7U uses the D315 engine. Engine balancer was not added until s/n 7U26583.

7u35268 what can you tell me about it. What year is it?

That 7U will have a lot more HP already over the 5T, You shouldn't need any more for "Tough Spots".
Ask anyone who has one of those "D5's" about the rear end being slopped out from too much horsepower.

So that's why they only made 40 something of them.
What year would this 7u be. Just curious.

7U35268 mfg. is early 1956.

5T hp is 44hp @ 1400 flrpm
The 112 grader got 52hp @ 1500 flrpm (D4400)

7U29424-37284 58 hp @ 1600 flrpm
7U37285 got 60.5hp
The 3U grader got 72hp @ 1800 flrpm (D315) with different governor and spring.

For comparison the 4R/5R D6 (D4600) got 70hp @ 1400 flrpm