i don't know if i have correct anything! i am just using the towers that were in the truck. it had a 327 partially installed when i got it. i don't think it had even been started. the towers look the same as on my 64 and i put a 250 in it, it had the original 230. i didn't look close when i changed my 292 in my 66 years ago and don't have it anymore. i always just saw the extra bolt hole on the frame and figured there would be one below under the grease below. there is really just one more hole on the frame so it uses one new one and one that was already being used. down below their is a slotted hole but it a couple of inches away from being where it needs to be. it is closer to the bottom of the frame instead of being in the same plane only foward. on a side note i found i need to get a engine mount bracket too. i had a pile of mount brackets but none will work. all the ones i have are like the drivers side one where the top bolt hole is recessed in a little. i wonder if all the block castings are the same or i have a pile of drivers side mounts.i checked and the 250 i have is the same and a 292 i have in storage too, but everything else i have off has a car bracket on the engine. on the block on the passenger side the bolt holes are all even in one plane. so i will have to try to rob one off one of my parts trucks. this hole pass side is turning in to a real pain in the rear. yea john if you could check that would be great or if anyone knows.