My lt1 had an piggyback underdrive pulley that I want to remove. I need to get new bolts for the crank however, since the bolts that are on now are way too long. Any idea what thread/length I need? Should I just get them from the dealership or can I find them in a hardware store?

 

A GM dealership may not have them in-stock, but will be able to get them in a few days. I think the three damper to hub bolts are 7/16 course thread, but I don't know the length.

WD

 

Thread size is 7/16x20 Bolt head is 5/8 and length I'm not positive on, think it's about 2.25. Maybe someone will chime in that knows for sure. There is a web page that has all that info but it's bookmarked on my home computer.

Edit: Just realized you might be talking about the other bolts. Yes they are 5/8 head 7/16 coarse thread (16?) and maybe 3/4 long?

 

Thanks guys. If anyone knows the proper length I'll just pick Them up from the hardware store.

 

7/16-14 thread for the pulley bolts.

 

Anyone know the length?

 

Posted on my website... 7/16"-14 x .88"

Sorry, I missed the need for the length earlier.

 

Thanks alot!

 

The OEMs are also a flange-head and probably a grade #5 or #8. So, a one inch should work if you're using a washer.

WD

 

Good point...I'll probably go a bit longer and get a lockwasher.