52 Oliver 77 cubic inches

Bore x bore x .7854 x stroke x # of cylinders.

Example: 4" bore, 4" stroke, 6 cylinders
4 x 4= 16
16 x .7854= 12.5664
12.5664 x 4 (stroke)= 50.2656
50.2656 x 6 (# of cylinders) = 301.5936
 
Stroke is the same, so just calculate it!

Pi r squared h is the volume of a cylinder.

Or pi d squared/4 times h

Pi =3.146, r = radius, d = diameter, and h =stroke.

RAB
 
Thanks everyone I came up with 265 so with stock crank cam and no headwork do you think this tractor would make 50 to 55 horse
 
here's an easy site to figure your stuff on . http://www.race-cars.net/calculators/compression_calculator.html

if you got that compression up to 11 to 1 you could get 75 hp . it would take a 25 cc dome on your piston though .
 
That set up would give you 265.34861718750005 cubes. I had a 77 with 55 horse. Stock stroke, 3 3/4" bore, stock cam, stock carb, stock valves, and stock RPM's. But it had 80 thousandths off the head. Ran premium fuel. Dont bore the sleeves or block or whatever youre doing (unless its already done.) Get murphys roller rockers and intake manifold. Shave the head .0100. 1550 or bigger carb with 770 valves and I bet you will have 65-70 horse. That's pretty good for no machining to the crank or block.
 
The block is already bored thinking of shaving the hed and bigger valves but I might just runit for a season as is to see what kind of power i have I am wanting to pull div II 4000 and 4500
 
I run the 3.75x3.75 in my 66. It is a super 55 engine with the late 550 head, manifolds and carb. The head is shaved .100 and everything else is stock. It pulls really well most of the time. You can see it pulling on youtube. 2014 Pa Farm Show Antique tractor pull - YouTube. It won the 3,000 and got 2nd in the 4,000. Lots of fun!! I use Sunoco 89 pump gas. I don't have the PTO in it so I don't know what the HP is, guessing more than 50 @ 2600RPM. Your 77 should be 60 or better at a lower speed with 3.875.
 
With the big pistons the head work will make it much better. Or get a late 770 or 1550 head for it. I'll try to take a look in my Oliver manual to find the valve sizes. The later manifolds and carb might be a good thing for that engine also. The later upper end really awakened my 4 cylinder. I worked on the carb this year to get rid of a lean problem on a long hard low RPM pull. I like it now, good torque at lower RPM.
 
Thank you everyone Lots of good info I think I am leaning towards doing work to the head, shaving and bigger valves just have to figure out what valve to use I am posting a picture of the tractor
a146209.jpg

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