Ok sounds like a plan. I have the current engine with 67 big port heads and rockers oiling through both the later 70+ pushrods and lifters and the 67 rocker shaft. It seems to be working fine and I had the driver valve cover off for the first time in 1k+ miles and everything seems happy.
Those are really strong rockers and are 1.59 ratio vs 1.55 for a little more lift at the valves. I use them, but I bought TA "HYBRID", ADJUSTABLE, TUBULAR, push rods because those 67-69 rockers have a larger cup. 1. Hybrid...solves the cup size problem. 2. Tubular... gets the oil into the rockers and closed style shaft. 3. Adjustable ...compensates for head and block milling, as well as irregular stem height if there are SLIGHT differences.
Do you recommend 5/16ths or 3/8ths Gary because of the larger cup size (3/8ths) of the 67 rockers? I think I know the answer...5/16ths on the lifter side and 3/8ths on the rocker side.
I don't think TUBE diameter factors in here. I use the smaller diameter rods just because the larger diameter can rub the rod passages in the head and get metal into the engine. You need to call TA Performance. IF you have a 430 block, the 430 lifters may not be compatible with the later style push rods. The 430 block has an oil passage hole that sends oil through a hole in the head, and into the rocker arm pedestal, then into the rocker arm shaft that has caps on both ends to hold the oil. To up grade, you need 70-76 Buick lifters, and "HYBRID" push rods that match the 67-69 rocker arms' large push rod cup . Therefore, the hybrid push rods fit 455 lifters on one end and 430-400 rocker large cups at the adjustment end (top).
I also have later style lifters as well. I’ve also been running 5/16ths tipped pushrods (on both ends) with my 67 rocker arms and haven’t had any problems for 1k miles.
Here are the correct push rods for sale http://www.v8buick.com/index.php?threads/for-sale-1-6-430-rocker-arms.350992/
