Panhead bored out cylinder deck?

[Panhead_Bobber_11C]

I just came across a set of 59 FLH cases. They are very nice. I just have a question regarding the cylinder deck being machined what looks like to be for big bore cylinders. Looks like later on they switched back to stock with these aluminum machine fitted rings. I added pictures so you guys can understand better as to what I'm talking about. I can't confirm why this was done but that's what I think. The engine was parted out and was running before being parted out.

[Rubone]

So what is your question??

[Panhead_Bobber_11C]

So what is your question??

My question is If anyone more intelligent than myself when it comes to panheads what exactly was done here. What I had stated is speculation of what I believe was done but I dont know for sure. My speculation is it was fitted for big bore jugs and then reverted back to stock (I.E the aluminum rings) Would like for someone to agree or have a different opinion as to why these aluminum rings were installed and why the cylinder deck was machined. You can see by viewing the photos I added. It's not stroked for a bigger wheel. Because the belly of the cases aren't machined for a bigger wheel. It ran a stock crank. I would appreciate an insight.

[kitabel]

That may be it.
However, it doesn't need to be done.
The stock spigot should be slightly smaller than the iD of the insert, not a snug fit.

[Panhead_Bobber_11C]

That may be it.
However, it doesn't need to be done.
The stock spigot should be slightly smaller than the iD of the insert, not a snug fit.

Ok so stock cylinders will work fine? How about the oil passage holes in the cases? Or will they just fall through the piston internally for return line?

[kitabel]

The engine may have been built for external drain.
f you use 1948-52 (deck drained) panhead cylinders (with drains in the flange bottoms) you have to drill through the deck down into the case interior,
For 1953-83 cylinders the drains are inside the bore.
The drains in the back of the ring grooves are only for oil removed by the oil ring, not the rocker boxes.

[Panhead_Bobber_11C]

The engine may have been built for external drain.
f you use 1948-52 (deck drained) panhead cylinders (with drains in the flange bottoms) you have to drill through the deck down into the case interior,
For 1953-83 cylinders the drains are inside the bore.
The drains in the back of the ring grooves are only for oil removed by the oil ring, not the rocker boxes.

Ok thanks for the info. These cases are 1959. So would like to use 53-64 barrels. So your saying I don't need to modify if I use those year barrels?

[kitabel]

Your barrels already have drains that end inside the bore, so the blank flange is harmless.
A stroked motor using those barrels (where the oil ring would travel below the drain at BDC) would need the holes extended down and through the case.

[Rubone]

Because the belly of the cases aren't machined for a bigger wheel. It ran a stock crank.

Not sure what you mean by that. Stroker flywheels are not larger than stock, only the crankpin is located in a different spot. The cases have visible notches for rod clearance which indicate a longer stroke was used.