Need help IDing cylinders
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2nd Gear
Joined: Dec 2023
Posts: 6
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From: Montana
Need help IDing cylinders
I have a 76 (I think) Shovelhead that supposedly had a 93” stroker kit installed with a Super G carb (I know. Too big for a 93”) but I’m having trouble IDing the cylinders. I have 9 fins on the jugs which leads me to believe they are 80ci jugs and the stampings are 16588-78 on the front and 16587–78 on the rear. I haven’t been able to find those exact numbers from searching but it’s making me doubt the 93” stroker claim. The previous owner also told me that it also has a C grind Andrews cam and solid lifters. The bike ripped even with the Super G so I never questioned the stroker claim until I noticed the cylinder stamping while in the process of redoing all the wiring. Any help with figuring out what I have before I have to pull the heads and start measuring? Also, the stamp on the engine case reads 2C12210H6. Thanks!
Road Captain
Joined: Jul 2020
Posts: 521
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From: Gainesville FL
I have a 76 (I think) Shovelhead that supposedly had a 93” stroker kit installed with a Super G carb (I know. Too big for a 93”) but I’m having trouble IDing the cylinders. I have 9 fins on the jugs which leads me to believe they are 80ci jugs and the stampings are 16588-78 on the front and 16587–78 on the rear. I haven’t been able to find those exact numbers from searching but it’s making me doubt the 93” stroker claim. The previous owner also told me that it also has a C grind Andrews cam and solid lifters. The bike ripped even with the Super G so I never questioned the stroker claim until I noticed the cylinder stamping while in the process of redoing all the wiring. Any help with figuring out what I have before I have to pull the heads and start measuring? Also, the stamp on the engine case reads 2C12210H6. Thanks!
H6 = 1976
12210 = Production number
Road Master
Joined: Mar 2012
Posts: 1,018
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From: Ohio
It can still be a 93" motor. 3.500" + 0.030" overbore = 3.530" x 4.750" stroke = 93".
Last edited by Ohio HD; Dec 2, 2023 at 12:31 PM.
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2nd Gear
Joined: Dec 2023
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From: Montana
Thank you very much. I’m going to see if I can ID that flywheel # and hopefully it adds up. That’s the fun part about Shovels I guess. I have a 76 case with 78+ jugs and o-ring heads that have band style manifold clamps. Gets a little confusing lol
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2nd Gear
Joined: Dec 2023
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From: Montana
Thank you very much. I’m going to see if I can ID that flywheel # and hopefully it adds up. That’s the fun part about Shovels I guess. I have a 76 case with 78+ jugs and o-ring heads that have band style manifold clamps. Gets a little confusing lol
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Road Master
Joined: Mar 2012
Posts: 1,018
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From: Ohio
I'm probably a minority, but I prefer the O-ring seal. As long as you have high quality clamps, that manifold will never budge or leak. You can always get a different intake manifold.
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2nd Gear
Joined: Dec 2023
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From: Montana
From what I’m reading on the S&S chart. The G 578 is the serial number, the 3 is the stroke code, which is 4.75, and the AL is the year code, which is 72-early 81. So I guess if the jugs are indeed bored .30 over then it confirms I have a 93” Do you guess see any potential issues with the .30 overbore? Thanks again for all the help.