Need Some Help - Sbc Torque Question

I have a SBC that I bought as a '69, and the casting date looks to be an 8. So it could be a '69 or '79.

There is a torque spec difference for main bearing and connecting rod caps between the Pre-'77 and the '77 and later 4-bolt main blocks.

The Pre-'77 call for 70# inner bolts and 65# outer bolts, where the '77 and later are 80# inner and 70# outer.

Not knowing for sure, should I go with the higher numbers...........or the lower ones?

Thanks in advance,
Unkledaddy

 

unkledaddy............I always used the 75# rule, not to be confused with the 75 minute rule. 75# on the mains inside and outside bolts (or studs), 75# on the rods (if aluminum) and 75# on the head bolts. You won't have any problems at 75# on the the main bolts. Torque the main bolts to 75# then fully back them off, then do the same again torque to 75# back them off, then do a final torque to 75#................ I also always use a soft hammer and tap the main caps down and make sure they are seated before torqueing. Hope this helps. 408 AA/D

 

Also uncledaddy, even if the block has been thoroughly cleaned chase all the main and head bolt holes with a 7/16 - 14 tap and clean all the bolt (stud) threads then apply a small amouint of light oil to the threads before ***embly. AA/D