t140 head on t120 jug

I overhead the boss man talking to an old friend about this at the shop I apprentice at. He wasn't familiar, but the friend said it was easy peasy if you fill one of the holes on the t140 head. They talked about the superiority of the head which is all well and good, but I might be interested for a different purpose - making a manifold to fit a weber DCOE carb that would align much better on a t140 head. can anyone walk me through what needs to be done for this swap?

Neither of the two center bolt holes on a T140 head will line directly up with the one hole on the 650 jugs. The front one is close,but not quite.

Originally Posted by dukerollo

Neither of the two center bolt holes on a T140 head will line directly up with the one hole on the 650 jugs. The front one is close,but not quite.

can they be filled with weld and redrilled using a 650 gasket as a template?

that's an an old flat track trick, the 9th 650 hole has to be welded up and then 1/2 of it has to be tapped for the T140 hole, but the only T140 head that is an improvement is th parallel port head (1978+)
If you are going to all that work for more power then get a 750 crank/rods and put the 750 jugs on there too. it runs much better at higher RPM.

power actually isnt even the primary goal here. just trying to do something a little different and looking at my options. Originally I was thinking a tr6 head, but the ports are really narrow and I'm not sure how I'd fit it. the t140 head with the removable bolt-on manifolds seems like the ticket.