i have my 64 wagon with a 289 and an automatic.
I have a 70 351w with low miles just collecting dust, and want to swap
it in for now.
Is it a direct swap, or do i need to worry about the balancer and flywheel?
You don't need to worry about the balancer or flywheel. But you will need another bellhousing or transmission as your 64 289 is a 5 bolt block and the 351 is a 6 bolt block. Find a C-4 or C-6 to fit the engine and it's almost a bolt in.