head cut for 74" pan cylinder

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dcmc
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head cut for 74" pan cylinder

#1

Post by dcmc » Thu Aug 08, 2019 6:33 am

I have an otherwise nice 5 fin Knucklehead head, that has been modified to fit a Panhead 74" cylinder, this has left the head with a larger volume since both the diameter and depth have been increased to clear the lip on a pan cylinder. I am wondering if this rear head could be run with a unmolested 5 fin Knuckle head ? The bolt hole is an easy fix. But trying to weld and machine such a large area in the combustion chamber seems like a bad idea.
Anybody have experience running this combination of mismatched heads ?

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1950Panhead
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Re: head cut for 74" pan cylinder

#2

Post by 1950Panhead » Thu Aug 08, 2019 1:17 pm

I have an otherwise nice 5 fin Knucklehead head, that has been modified to fit a Panhead 74" cylinder, this has left the head with a larger volume since both the diameter and depth have been increased to clear the lip on a pan cylinder
A machine shop could make a ring so both heads have the same volume.
FL cylinders are flat on top, knuckle and pan EL cylinders use the same bore, 3.312".

dcmc
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Re: head cut for 74" pan cylinder

#3

Post by dcmc » Sat Aug 10, 2019 7:42 pm

I was thinking of the possibility of finding a piston ring for a 3 3/4" bore and silver soldering it to the head. But I don't see tying to weld anything in that area since penetration and dissimilar materials would be an issue.

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