wyocutlass

I have a 68 cutlass supreme. It has a 350 but I am wanting to swap it for a 455. I have search and can not find the answer I am looking for but I found a 455 that came out of a 76 custom cruiser wagon. Will an engine from a 76 work? Or does it have to be before?

Fun71

All Olds engines mount the same, so it will bolt in just fine. You will need to use the engine mounts for the 350 so that the 455 sits at the correct height. Mixing the engine mounts and frame pads for 350/455 results in the engine being at the wrong height.

joe_padavano

In 1968, the SBO and BBO used exactly the same motor and frame mounts in the Cutlass line. It wasn't until the 1969 model year that different ones were used, but as you correctly point out, so long as they are matched, it doesn't matter.

To the OP, all 1965-1976 big block Olds motors (400, 425, and 455) are externally identical. Be sure to get the A-body exhaust manifolds (or headers if you choose) for your car.

Backstrom

The only difference that I can think of is that the drain petcocks is located differently on fullsize blocks, behind the motor mounts when in a-bodies, and that it probably doesn't have the treaded hole for the clutch linkage boss.

Fun71

Some of the accessory brackets are slightly different between the SBO and the BBO, and at some point the bracket style changed - I think that was in the later '70s but I am not sure.

wyocutlass

Thank you for all the information. I knew that the motor mounts were all the same and all the things that are required for the swap. I just didn't know what years of engines would work for it.

Octania

There will be very little difficulty
When in doubt, for your 455 powered car, pretend it's a 442 and order that part. E.g., if buying new motor mounts, and why wouldn't you, buy 'em for a '68 442. Buy exhaust manifolds or headers for a '68-72 442.

do not throw away ANY parts until you are done.
Compare the new part to the old - like motor mounts- and make sure the new will work.

Use the water pump and pulleys off the car's original engine unless you wish to use the '68 442 setup which is probably all different due to a different water pump. Water pump and pulley setups tend to be a matched set, so when you mix and match there it becomes a headache real fast.

brackets should all interchange- I believe the SB-only brackets came about for model year 1977, when the BB was dropped forever.

While the engine is out and you are putting all new freeze plugs in and whatnot, why not drill and tap the block drain bosses that will be uncovered with the motor mounts in place, so they can be used? 1/4" NPT pipe thread

Your 1976 455 will probably have HEI so that requires a new feed wire w/o resistor, and probably some bit of tailoring of the vacuum and mechanical advance and whatnot. The more changes you make, like headers and cam, etc., the more the spark curve will need attention.

'68 has some unique one year only things like the throttle cable. Are you changing '68 350 2bbl to '76 455 4-bbl?

joe_padavano

While this SHOULD be true, the unfortunate fact is that most vendors have this wrong. They list the 2328 mounts for 68-72, when in fact they are only 69-72. The 68s used 2261 mounts for both SBO and BBO.

And while Chris's info applies for headers (just don't ask for headers for a Supreme), if you choose stock manifolds you want the 69-72 W/Z manifolds, not the 68-only X/Y manifolds. The later ones have divided runners and flow better.

wyocutlass

My car has a 4bbl. I found another engine for sale. Its a 70, and he wants 350 for it but it looks like its in rough shape. What do you think? I should be able to talk him down to 150 possible00d0d_dhLM1EYWvKH_600x450.jpg

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70vert

Those picture are of a Buick motor. That will not just bolt up without major modifications.

wyocutlass

Thank you for the information. The guy has the post as a oldsmobile.

64Rocket

What is your location? There was a guy around here listing a Buick engine as an Oldsmobile.

Gene

Octania

what is the need to change the 350 into a 455?

Bad engine, or powerlust?

wyocutlass

Always wanted a cutlass with a 455. As long as I could remember.

oldcutlass

Can't argue with this logic...

joe_padavano

Jeeze, Chris. Don't make me take away your Rocket Card.

MDchanic

The '70 Buick 455 will pull a lot harder than any '76 motor.

Just get motor mounts for a GS, change the exhaust, make a few wiring changes...

Sorry, couldn't resist.



- Eric

Fun71

To continue the above, the Buick engine will bolt up to your Olds transmission.