77 build up

Anonymous-0 · Apr 21, 2013

Wondering if my plans would work ok. 77 block bored to take some used 3 7/8 M&W sleeves for an 88 that I have , bored .030 or so over using 283 chevy pistons, Bullet cam,770 crank stroked approximately 1" or a little more to make the pistons come up to the top of the deck with 77 rods,flowed 770 head with 550 valves and a 770 carb and intake, That will make 341 ci. Not looking to build a monster just a reliable speed limit puller

ss409 · Apr 21, 2013

turn down the top sleeve flange so your not over boring the top of the block. May have to cut a little off the bottom of the sleeve too. ive put 88 sleeves in a S66 n its not bad to do n held water. look at dodge 318 pistons. 3.91 bore at 1.75 compression height.

Anonymous-0 · Apr 21, 2013

I figured the distance from the center of the pin to the top of the piston on a 77 piston is 2.295 so if I take off .500 for half the stroke that leaves 1.795, exactly the comp. distance of a L216F power forged piston for a 230/283 if my math is correct, I will look at the 318 pistons though, a person still has the option of using an offset pin bushing to get it exactly right. Would this set-up make 80-85hp if everything was done correctly?

ss409 · Apr 21, 2013

the reason I mention 318 pistons, is they have wrist pin clips stock. you can offset the bushing quite a bit, up, or down to perfect rod centerline distances. cyl head porting alone, with bigger valves to help feed it. 75-80 out of that ci could be an underestimate. I had a old 77 I bought for 500 a long time ago. dyno 42hp all day long. fun lo gear tractor.

johns · Apr 21, 2013

Doug are you going to have both the crank offset ground and welded to gain the 1" extra stroke?

Anonymous-0 · Apr 21, 2013

the 526P piston for a 318 also has no valve reliefs for compression loss, the little difference in comp. height can be made up in the stroke or or offset bushings or shave the piston a few thousanths, my restored 77 with 3.5 pistons will run 41hp at rated speed, 44 crankdown, were building a puller out of a 1950 $400 dollar runner we bought at a farm sale last summer

Anonymous-0 · Apr 21, 2013

yes ,welded up and turned down to a 2" 77 journal

Bryce · Apr 21, 2013

With the 770 crank you will have to relieve the rod at the top on alternating sides otherwise the rods will squeeze the pistons in the cylinders with 77 rods.

Anonymous-0 · Apr 21, 2013

oooooo, I suppose they use offset rods like a 1550. what about a 2.250 journal super 77 crank

bock · Apr 22, 2013

just bolt in a 320 our 310 it would be alot cheaper and more reliable, and make more power , if your rules allow it. got a 320 for $1200 6182466030

Anonymous-0 · Apr 22, 2013

they're not national legal, we've got a couple of people that pull with us that took the easy way out and put in 310's, a few of our local pulls do have rules against it but it hasn't been enforced, my intent is to build something that will be competitive with the correct block for the tractor

Bryce · Apr 22, 2013

dont know about the s77 crank ,but yes on the offset rods.

77 build up

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