..... you check the pushrod lengths? I mean, a 360 has a certain length pushrod, (I am nowhere near that info) is it the correct length of what you have?
I've had the very same 273 factory stock adjustable pushrods on ever LA small block there is. 1 They came off a 273. 2 Ran them on the 340. 3 Ran them with the 318, and now, 4 on the LA 360 in the 67