Chicken or the EGG??? Should I buy motor mounts to fit the engine or the frame?

[akejama]

MY SITUATION: I recently bought a 1966 Cutlass Covertible for a driver, not a show car; I can't sit still long enough for shows. This 66 cutlass came to me with a mid 70's (1974 I think) 403 motor installed that runs quite nicely. It seems well suited to the transmission, is pretty easy on gas, starts every time, and happily burns today's junk gas without complaint.

MY PROBLEM: I do notice that the motor torques up when I accelerate quickly, so I am going to assume I have a motor mount problem.

MY STUPID QUESTION IS: Assuming the mounts weren't properly installed by the previous owner, should my primary concern be finding motor mounts that are a perfect fit for the engine or a perfect fit for the frame? Or by some quirk of fate might I actually expect to find mounts that will work without alteration or welding? I figure asking here is the wisest course of action since I usually get pretty good advice. Obviously I'm a green horn learning as I go, so any and all advice is appreciated.

[joe_padavano]

The motor mount attachment holes on ALL 64-90 Olds V8 blocks are in exactly the same location. You MUST use the rubber motor mounts that match the frame mounts in your car. Assuming your 66 has the original frame mounts, you need Anchor P/N 2261 motor mounts, or equivalent. These allow ANY Olds motor to bolt into your car, including a 403. By the way, the 403 is externally identical to the 330 that your car was born with. Any external part that bolts to the 330 also bolts to the 403. The only exception is the flywheel/flexplate. The 64-67 motors use a different crank flange bolt pattern than the 68-90 motors.

[NTX5467]

In the GM cars back then, the "mount" was a two-part situation. The basic crossmember might have been common to the GM A-cars back then, but the "frame mounts" or "stands" had to match the brand of motor going into the car, due to a different relative position they had on the crossmember itself, not to forget the varying heights of the particular stands. What bolts to the motor would be termed "motor mount", which would be what bolts to the "frame mounts" or "stands" and also to the mounting lugs on the engine block. That would be the item with the part number Joe referenced.

In the time your vehicle was manufactured, it was somewhat common for the rubber part of the motor mount to delaminate from the metal on either side of it, on the driver's side of the car. It's possible that the later versions of those mounts have a "fail safe" link in them to limit engine movement/torque reaction should the rubber fail.

Nice car with an "incognito upgrade" for the engine! Please keep us posted on your progress.

Just some thoughts,

NTX5467

[joe_padavano]

It's possible that the later versions of those mounts have a "fail safe" link in them to limit engine movement/torque reaction should the rubber fail.

They do. The Anchor 2261 mounts I noted above have the interlocking "fail safe" feature. The original mounts do not but the 2261s will replace them with no problems.

[mike brady]

Joe should get $1 for every time he has answered this question.

[akejama]

Wow! Problem solved with the p/n # even.....thanks. The help I have rec'd here has been nothing short of extraordinary. I do so appreciate the help. Its just great to have people share thier knowledge and time. People I most likely will never get to thank face to face. None the less, I do appreciate what I consider a most generous gift. so THANK YOU, Tom

[akejama]

In the time your vehicle was manufactured, it was somewhat common for the rubber part of the motor mount to delaminate from the metal on either side of it, on the driver's side of the car. It's possible that the later versions of those mounts have a "fail safe" link in them to limit engine movement/torque reaction should the rubber fail.

Nice car with an "incognito upgrade" for the engine! Please keep us posted on your progress.

Just some thoughts,

NTX5467

And YES, Today when I examined the engine on the lift I could see the rubber was totally destroyed. So, thanks to you and Joe I'm on my way to getting a satisfactory repair completed. I was also very glad to learn that the 403 was pretty much a 330 in disguise so far as looks go. That is really kind of neat to know. Everyone here is just great to share their knowledge. Father time has taken most of my friends over the years ... so at this time of year its particularly nice to have new friends show up to take the time to help you out. Bill, and Mark, and Brady knew all this stuff but unfortunately they took their knowledge with them. I didn't get interested in working on cars till I turned sixty-five, so I'm having to ask questions that most probaly think silly. I try to research stuff before I ask, so as not to look too totally stupid, but sometimes I just need some help even framing the question. Godspeed, ya all made my day brighter, and my car run better. How cool is that? Tom

[akejama]

Assuming your 66 has the original frame mounts, you need Anchor P/N 2261 motor mounts, or equivalent. By the way, the 403 is externally identical to the 330 that your car was born with.

Joe, I sure appreciate your time reading my question and your very informative response. I plan on effecting the repairs this week. I'll let you know how it comes out. Thanks for giving me such great information. Godspeed, Tom

[NTX5467]

Tom, do not hesitate to ask questions in here -- period! Joe has an outstanding amount of knowledge on Oldsmobiles. My knowledge is more GM-general by comparison, with some carlines I know more about than others . . . if a customer asked something I didn't know, I did what I could to find out so I would know the next time somebody asked that question . . . having been in GM parts for over 30 years AND being an inquisitive car enthusiast before that. Others in here have similar or related experiences which we're all glad to share with those who might need some assistance.

In some cases, you might want to venture down into the Oldsmobile section of the forum, too. I believe there's a "Search" function which can be used to look at archived posts/threads on particular subjects. Or just ask again.

Happy Holidays!

NTX5467

[joe_padavano]

Joe, I sure appreciate your time reading my question and your very informative response. I plan on effecting the repairs this week. I'll let you know how it comes out. Thanks for giving me such great information. Godspeed, Tom

Glad to help. Any Olds that doesn't get a small block Chevy transplant is a good thing in my book.

[akejama]

Glad to help.

No problem getting the Ancor P/N 2261 mounts which cost less than $10. at Auto Zone. So, I drove the Cutlass over to my shop to install the mounts only to find that the 1965 Jestar 88 that I had left on my lift a couple of weeks ago had sprung a leak from the water pump, so decided to just go ahead and replace it and then work on the Cutlass. I finished the water pump and moved the Jetstar off the lift and parked it outside. When I came around the building to move the Cutlass onto the lift I found that my wife had parked her Jeep on the lift expecting an oil change and reporting a squeaky noise in the driver side front wheel. Squeak turned out to be a bad wheel bearing which meant replacing the spindle. Normally not a bad job for me to do, but the rust gremlins had welded the old nuts tighter than David Bowie's jeans, so long story short the Cutlass is still sitting in the bay and it will be Sat. or Sun. before I can get to it. I'll have to report the outcome later. Thanks guys, and happy holidays to all. Tom