1968 Porsche 911L Trans

[Targa68]

I have a 1968 Porsche 911L soft back Targa.
I bought a 1968 911L engine sixteen engines away from my original,thats close.
My Trans axle is from a 1965. It's in the car for the last 36 years. I was looking for a 1968 911L trans but I think i might as well rebuilt the 1965 Trans. One last try my Trans Number is 3280504 (902/1) it has to be aluminum. Any way the trans that I have the synchro rings in first and 2nd are weak. I'm to old to keep sealing this Trans. What's the best kit to get? Sealing the Trans getting the synchro rings and the fork.