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BillB · Joined: 25 Mar 2005 Posts: 267 Location: Allen Park, MI

I'm getting ready to drop in a BBO in place of my small block that sat approx. 2 inches too low. The old frame pads and motor mounts were small block. Car is a 1970 Cutlass S.

Thinking about keeping the old frame pads but using big block motor mounts - that is supposed to move the engine up by 2 inches or so, I believe.

Problem is the interlocking tab. Considering modifying the small block frame pads, but got to thinking...the Olds suppliers such as Fusick have big block motor mounts from 68-69 and another design for 1970 big blocks.

So, I'm wondering what the difference is, and could I use a 1968 BBO motor mount without modifying it, and get the height rather painlessly.

Any opinions on this?

TIA,
Bill Confused

rallye bob · Posted: Tue Jun 20, 2006 8:45 am Post subject:

Do not mix BB-SB frame pads with BB-SB motor mounts.
It always causes problems. Crying or Very sad

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BillB · Joined: 25 Mar 2005 Posts: 267 Location: Allen Park, MI

BlackGold · Joined: 14 Mar 2005 Posts: 2100 Location: West Michigan

The '68 BB mount does not have the interlocking feature. '69 is when they re-designed it. I can't tell you if it's possible to mix and match, but I doubt it. I commonly hear '68 owners complain when the parts store gives them later mounts.

What makes you think your engine is 2" too low?
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Brian

BillB · Joined: 25 Mar 2005 Posts: 267 Location: Allen Park, MI

I know the engine is too low because the fan doesn't line up in the shroud, leading to overheating since I had to cut the bottom of the shroud out.

There's other reasons that I know it sits too low, but the fan alignment is key.

68IOU1 · Joined: 03 May 2006 Posts: 952

The '68 uses the short motor mounts for both 350 and 400. You can use the correct big block mounts for '69 and newer but you must use the corresponding frame pads. Do this while the engine is out of the car.

This is besides the point, anyway. The fan should be in the same location as the previous engine if using the original mounts. The difference in height starts above the timing cover. Big olds is just a tall deck small olds. You have issues elsewhere (like incorrect fan shroud for that year or bent frame horns or your fan shroud should be mounted to the bottom first then shimmed on top).

CHRISH8846 · Joined: 08 Mar 2005 Posts: 648 Location: SUMMERVILLE,SC

Several posts on here refer to BBO and SBO mounts and pads not mixing. I was new to the Olds eng when I pulled a stock 350 from a 71 Cutlass convert and installed a 461. I bought BBO mounts from Advance (overlapping straps) and installed them on the frame pads that were in the car. I did not have to move anything or drill any additional holes. After reading the various posts on here about this topic I don't understand why I did NOT have a problem. I can tell you is what I did.
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71 CUTLASS CONVERT 461