The mounting bracket bolts should be fine with either grade 5 or the 8's.Yes the 8 is stronger and I'm not even sure there was a grading system for bolts in 1960 so the 5 was the bolt of choice.The fine thread bolt will give you more holding strength due to the threads per inch so they would be my choice.


In the works 2006 GEN III 6.0 /4L80E/ 205 New process,A/C and power brakes .