Motor mounts..Bolt or Weld

[cottonme173]

So, I am putting a 454 in a '78 that started life as a diesel so, the motor mount holes do not line up. First thought was to set the motor mark holes and rill the now ones..easy peasy... I started thinking though...would this weaken the frame just that much more putting more holes in it? So, the other option is to weld them in and eliminate that issue (if it is one).

What are your thoughts given this situation? I am a good welder and have one, so that's not an issue. I will never put anything but a BB or SB in the truck so I wont need to move them.

Thoughts?

[74CustomK20]

I thought all the trucks used the same mount holes n just moved transmission cross member?

[cottonme173]

Originally Posted by 74CustomK20

I thought all the trucks used the same mount holes n just moved transmission cross member?

The 454 I have came out of a 1977 c20. I kept the mounts and the truck i'm putting it into is a 1978 c10 that had the 6.2 Diesel in it. I wish you were correct, but my holes don't line up.

[DieselSJ]

Originally Posted by cottonme173

The 454 I have came out of a 1977 c20. I kept the mounts and the truck i'm putting it into is a 1978 c10 that had the 6.2 Diesel in it. I wish you were correct, but my holes don't line up.

They should. The SBC, BBC and 6.2/6.5 all share the exact same mounting dimensions.

[kwmech]

1978 would have the infamous 5.7 olds diesel. The 6.2 did not come out until '81-82. It it truly had the 6.2 it was converted and if the mounts don't line up with that being said you have other issues

[cottonme173]

Originally Posted by kwmech

1978 would have the infamous 5.7 olds diesel. The 6.2 did not come out until '81-82. It it truly had the 6.2 it was converted and if the mounts don't line up with that being said you have other issues

Well that explains a lot! When I bought the truck there was no motor in it. It did come with 2 diesel motors a 6.2 and a 5.7! The PO told me the 6.2 was in it, but as it turns out from other issues I found, he was probably mistaken. So the 5.7 did have different alignment holes for the motor mount and that's why mine wont line up?

[sweetk30]

and true 454 frame mount holes the rubber mount bolts to have a different BIGGER pattern spread.

if you ever have to change the motor mounts ( oem style replacements suck anymore ) you will be cutting off and re-welding .

I did a 454 swap in my k30 that was 350 stock . I set it level and square to old and marked and drilled the correct holes.

[cottonme173]

Motor mount bracket by UNFORGIVEN173, on Flickr

I must apologize that i have misspoken about what exactly I am talking about. In the picture I wount to weld the bracket that the motor mount attached too. Bracket to frame is where the holes do not line up.

[kwmech]

Drill them out and bolt them, welding won't hold up in the long run---'specially with the diesel

[sweetk30]

some frames come multi holed some didnt . so drill and bolt would be best . and use crimp lock nuts aka stover nuts . lock washers suck anymore . and factory used stover nuts .

[cottonme173]

Originally Posted by sweetk30

some frames come multi holed some didnt . so drill and bolt would be best . and use crimp lock nuts aka stover nuts . lock washers suck anymore . and factory used stover nuts .

Thank you! I will go the bolt route.