hello i am being given a 69 302 block and 67 289 heads. i have heard that i may need to drill some water ports in the heads to match the 69 302. is this true or is this only for the newer blocks. the topic came up to me that i may have to use 289 pushrods. is this true. i have both non HO pushrods and HO pushrods. can i just use the non ho pushrods and adjust the valves accordingly. thanks, i did search.