It's a big job, and not worth the effort. It's been done many times, with the common comments being "I wouldn't do it again".The AVL pumps are not positive displacement pumps, so they allow drain back from the return lines which is a partial contributor to wet sumping issues in the AVL. They do pump more oil, but they over oil the head, so you must have valve stem seals fitted, which many iron barrel engines do not have as standard equipment. Otherwise, you will get oil down the valve guides which can cause higher oil consumption and even cause detonation when it gets into the combustion chamber. It's not hard to fit seals, but they are a must with that much oil in the head. Also, the floating bush OEM big-end bearing may build too much pressure with that much more oil feed, causing stress to the pump drive spindle when the oil is cold, possibly stripping teeth off. The AVL pumps were made to feed a roller bearing big-end, which needs more flow and doesn't hold pressure. I recommend hi-flow positive displacement pump replacements for the stock iron barrel pumps when changing to an Alpha roller bearing big-end.
The oil isn't responsible for much cooling in this engine. It is mostly air cooled, and the oil doesn't do much of the cooling. Your best course for cooling improvement is to fit an alloy barrel with that new piston. And hone a correct piston-to-wall clearance for that forged piston, so it won't seize. The amount of clearance depends on the type of piston.
And last, but not least, do not push the working compression too high for the intended fuel. Unless you intend to use the Indian 97 octane fuel, you will need to keep the working compression under about 135 psi on a cold cranking compession test.
These recommendations come from a lot of hard won experience. Failure to observe these guides will yield costly problems.