Hey,

Does anybody know the torque spec for main caps on the 1965 425 engine? I've read 120 ft lbs, but I want to make sure as in this is kinda important.

Thanks in advance!!!

 

The 1965 manual says 80 ft/lbs for #s 1-4 and 120 for #5, like for a small block, BUT
The 1966 manual (and all subsequent manuals) says 120 ft/lbs for all.

I believe that the 1965 manual is simply mistaken, and they should all be 120, as there is no diference between the main bearings of a 1965 block and those of later big blocks.

Any contrary opinions?

- Eric

 

My 66 Motors manual says 1-4 80#, 5 120#

 

FWIW, here is a link to the torque specs from Olds 65 CSM. The 425 specs start on page 3-92. The engine specs are before that. Hope you will be able to use it. http://wildaboutcarsonline.com/membe...Section_3C.pdf

This info courtesy of the Website "Wild About Cars" - free to join, free to share.

 

This is not the first time I've seen this topic and the different answers. I've always wondered myself because the bolts are the same diameter yet different lengths. I've also seen others listed as 110-120# for all. I wonder if anyone has a good answer for this?

 

Thank you so much for the info guys. In that link Allan R gave me it mentions both the 80 and 120 ft lbs, but I've also read 120 ft lbs for all 5 caps. It is a pretty big difference so now I'm totally stumped!

 

Like I said, if you read the '65 manual, it says 80/120.
If you read any other manual, it says 120.

And there's no difference in the block or the bearings.

Use your judgement.

- Eric

 

The 330, and 350 have smaller bolts (7/16ths) on #1-4 main caps, thus the 80 lb/ft spec. Just like the early heads.
#5 has 1/2 bolts, thus the 120# torque. Just like late model heads.
The 425 has 1/2 main bolts on all caps 1-5 with the 120# torque required.
If you have doubts, measure your bolts/fasteners.

 

So do 120 ft lbs on all main caps??

 

I would.

- Eric

 

Yes,Yes,Yes.
1/2 bolts require 120 lbs.

 

7/16 x 14 thread bolts would be torqued to 80, 1/2 x 13 bolts to 120. See what bolts are used for each main cap, and go from there.

 

They are all 1/2 bolts. The only difference with number 5 is that its longer. Im going to torque them and check for out of round. Thanks!!!