When you go shopping be careful which flex plate bolts you end up with, although the thread sizes are the same the post 86 crank bolt hole mounting diameter is smaller so the heads of the normal bolts end up so close that there is not enough space between them to get a socket on to do them up, you need bolts with a slightly smaller head, I used ARP ones, fairly sure these are the right ones:Hi Chevyvs
Thanks for the comment. I've learnt a lot about flex plates and flywheels in the last few weeks! Funny when something goes wrong it opens up a whole new world of dos and don'ts, get this and not that and make sure you check the other thing first blah blah ! :shake: So much for 'it should just bolt straight on' !!
Having a 89 Chevy ZZZ crate engine with in line starter mounting holes it is definitely a 153, externally balanced item I'm after. Thought I'd try on here first before going to the shops.