Oliver 77

[4010 puller]

What all can be done to 77 gas engine to get more
power if a guy had one tore down to rebuild? Are
some boring/stroking factory engine or moving up to
the 310?
 

[supermpuller]

400 cu. and bigger
 

[SPT]

Neighbor had 77 with 440 cubes.
 

[VicS]

A 320 is better. But a 426 is better yet.
 

[Dblair]

to get to about 75hp port the valves to 880 and increase the compression to 12 to 1 .
 

[jd man wis]

They pull good with the up date kit that use to be from MW kit. I would frist check on the class you want to pull because you can build a big motor only to be held down because of a speed limit an then you might have to drop a great and have to much power an spin out. I know that a fresh up motor in it and running good that in a stock class there hard to beat.
 

[Gary Mitchell]

I had 330 cubes in mine, 770 head and manifolds, larger MS carb, and it had more than enuf hp to pull in any of the classes I wanted to fool with. This was in the 3.5 mph era for class III classes. I'm satisfied that 5 MPH would have improved the performance. gm
 

[560Dennis]

Wow 😳 440 almost like those John Deere g with 1200
 

[forty40]

Antique tractor pulling...build what you want, how you want to build it. Above 3-1/2 mph, a 77 motor will require at least stroking and compression increase along with a cam regrind. A stock 310 is 100 more cu-in and 2x the hp of a super 77 motor so thats the beginning. Stroking, boring, custom sleeves, pistons, and rods cost about the same for either. 12 port stock head out performs the best reworked 9 port on the flowbench. Drawbacks to the 310 are weight +200 lbs and spare parts like a good used crank are nearly impossible to find without buying a complete engine.
 

[4010 puller]

Hi Vic, are both your tractors running and ready to go or is the allis still down? You can email me if you would like. Did you ever find that magazine with the 320 article in it?