The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

**69Tom** · 11-29-2021, 01:18 PM

Have a question for you guys. All the bracketry was removed from my engine for the stock A/C system prior to my ownership. Stock 74 454 truck. Since sourced said brackets, now I need bolts to connect them.

Are the threads in the heads and block to mount the brackets fine or course threads? They seem to be coarse, but I didn't want to screw up the threads by tightening in my test bolts (I still need to get the correct lengths)

Also, should I go with grade 8 for strength or 5 so there's some slight flex so they don't just shear off due to potential vibration?

Thanks.

11-29-2021, 01:18 PM	#1
69Tom Senior Member Join Date: Jul 2015 Location: Phoenix, AZ Posts: 1,333	A/C bracket bolt question Have a question for you guys. All the bracketry was removed from my engine for the stock A/C system prior to my ownership. Stock 74 454 truck. Since sourced said brackets, now I need bolts to connect them. Are the threads in the heads and block to mount the brackets fine or course threads? They seem to be coarse, but I didn't want to screw up the threads by tightening in my test bolts (I still need to get the correct lengths) Also, should I go with grade 8 for strength or 5 so there's some slight flex so they don't just shear off due to potential vibration? Thanks.