AT rebuild/update question

[drivfour]

I am in the process of rebuilding auto trans. I appreciate earlier posts saying the manual conversion is cheaper. I am planning to buy kit wholesale < $300 and have a question. The at history indicates the pump gasket was improved and the high drum and hub were changed by adding holes to improve flow for cooling. Can the existing, 1992 components be modified (add holes) - if so has anyone documented change? I have not yet looked into new drum/hub or if they are available. Seems this is the main change that new rebuild parts will not correct. I do plan to add a cooler with filter -stand alone from existing along with synthetic..

Thanks

JD