[keith]

I am replacing harmonic damper on my 1965 289, borrowed install kit from auto-zone to do install. None of the included studs appear to fit the crank threads. Everything I have read indicates the crank thread should be 5/8, 18 thread. that size stud from the kit is too large the 9/16 is too small. Is there another size or thread count that I should look for or do I have issues with my crank threads? any help is appreciated. As to the where abouts of the initial harmonic damper bolt I left it with engine builder, I know foolish mistake,

 

[rex1965]

Well for starters, not just any bolt will work, first off it is a grade 8 bolt, the head is 15/16", as for the thread pitch and dia, 18 tpi (is a machine thread not course thread at that dia)and 5/8" sounds about right. It may be that some of the bolts in the kit are metric. My 2 cts. Good luck.

 

[keith]

thanks for the help, I think I now know what occurred. I used an impact gun with the puller to remove the previous HB and in doing so flattened the crank threads close to the opening. The correct bolt to pull on the new HB can not be started. I will attempt the correct condition by using a 5/8 18 machine thread tap to chase threads. Hope it works thanks again.
I think a precaution regarding the possibility of damaging crank threads during HB removal should be noted on some of the you-tube how to videos. If this issue was mentioned I must have watched all the wrong instructional videos. oh well, more lessons learned

 

[rex1965]

If you use a correct balancer puller, and turn the bolt with a wrench or ratchet, it comes right off, I've never had any trouble pulling a balancer. Glad you got it figured out. Good Luck.