Can 80ci. Motor Internals fit in 1975 74ci. Cases?

Can 80ci. Motor Internals fit in 1975 74ci. Cases?

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Derek43WLC
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Can 80ci. Motor Internals fit in 1975 74ci. Cases?

#1

Post by Derek43WLC »


Can Shovelhead 80ci motor internals fit in 1975 74ci. cases?
What modifications?

Thanks,
D.
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Re: Can 80ci. Motor Internals fit in 1975 74ci. Cases?

#2

Post by RUBONE »

Derek43WLC wrote: Wed May 25, 2022 7:55 pm
Can Shovelhead 80ci motor internals fit in 1975 74ci. cases?
What modifications?

Thanks,
D.
Yes. Other than checking clearances in a couple of places to make sure there is no contact with the crankpin nuts and rods at top of stroke there are no mods needed.
Andygears
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Re: Can 80ci. Motor Internals fit in 1975 74ci. Cases?

#3

Post by Andygears »

By internals, I assume you mean flywheels, rods, sprocket & pinion shafts. They will all fit the cases. The pistons however need to be dealt with. Either boring your cylinders to 0.060 oversized to accommodate the stock 80 inch pistons, or obtaining a set of “stroker” pistons. Either piston has the piston pin located nearer the top of the piston which is needed because of the longer stroke. When Harley increased displacement in 1979/80, both the stroke and the bore were increased.

Andygears
Derek43WLC
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Re: Can 80ci. Motor Internals fit in 1975 74ci. Cases?

#4

Post by Derek43WLC »

Andygears wrote: Thu May 26, 2022 12:10 pm By internals, I assume you mean flywheels, rods, sprocket & pinion shafts. They will all fit the cases. The pistons however need to be dealt with. Either boring your cylinders to 0.060 oversized to accommodate the stock 80 inch pistons, or obtaining a set of “stroker” pistons. Either piston has the piston pin located nearer the top of the piston which is needed because of the longer stroke. When Harley increased displacement in 1979/80, both the stroke and the bore were increased.

Andygears
Thanks Andygears...I have the 80ci. cylinders & 80ci. pistons, so, is that good? ...I'm not using 74ci cylinders or pistons. I also have the the complete heads off 80ci.

Thanks,
Derek
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Re: Can 80ci. Motor Internals fit in 1975 74ci. Cases?

#5

Post by RooDog »

You're ready to rock & roll.... Make it happen.... But don't expect some high output hot rod from this setup....
....RooDog....
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