So my never ending 292 project engine has found a new home, namely a 1955 Pontiac(Canadian made)which is all 55 Chevy underneath. Couple of questions-where do I start with motor mounts? I have the offset passenger mount from when this motor was going into my 64 GMC but I don't know if that will be required anymore. Additionally since the Pontiac is V8 equipped, it's got front mounts(as would the 6). Would I start with a set of V8 frame mounts to begin with? Additionally has anyone run into steering or shifter linkage issues when going to aftermarket power steering? I'm not doing that quite yet but am planning for it. Thx, Ted.

Nobody here has swapped a six into an originally V8 car?

Let me kick this off.

Are you using the original transmission? -or?

Ha ok. No, '89 700r4. My basic question is how to start with side mounts. Am I going full custom or do I start with a specific type or brand of motor mount? I am aware that the trans mount will be different.

Pretty sure no one sells a kit. It's easier to weld on the frame than the block so start with the stock 292 front mounts and check what frame mounts were used. Something might be close. Length and height will be the issues. Clearing the crossmember and the hood may be tough. The front 292 mounts are off set. It sounds like a fun project. Keep us up on your progress please.

Look for the parts required to install a period correct inline chevrolet six cylinder in a '55 Chevy. They all used the transverse engine mount that bolted to the front of the engine!! Fabricate a mid-plate for the rear of the engine to be bolted between the engine and transmission and weld on tabs to use the factory rubber mounts from a '55 Chevy. Finally, fabricate a crossmember to facilitate use of a transmission mount for the 700R4.

The engines in those tri-five cars mounted originally on four rubber biscuits attached to a transverse engine bracket at the front of the engine and on the bell housing. That configuration didn't support the use of modern aluminum cased automatics. The Powerglides, Hydramatics, and Dynaflows of the day were cast iron and didn't need the rear support. That 700 WILL!!

The Pontiac frame and the Chevy frame may be a little different. GM didn't start consistently using common platforms for another eight or ten years, but they'll be really close! The toughest part to find may be the front transverse mount. The rest will require some sheet steel, (I used 10ga for my mid plate) or 1/4" plate aluminum, (hard machine grade) and some steel tubing and maybe some angle for the trans mount.

This is NOT difficult to do!! I've done it in a one car garage with hand tools and access to a welding machine at a muffler shop!!

The folks over at Chassis Engineering may have some parts that could get you started.

YESSIR!!

Blackwater, thanks for the encouragement. Is what you're talking about a six point mounting system? I'm looking to use the side mounts from the 292, and definitely a rear crossmember for the 700r4. I stumbled on the Chassis Engineering site a couple of days ago. Those mounts look like a solid mount from the engine to frame. I'm guessing I'll have to get my hands on the engine side mount and fab something at the frame. Do the 292's have a provision for the old style front mount cushions? If so I guess those could be used as a locator to start with?

Thx beater I think you may have answered part of my above questions already. Keep in mind this is a Canadian Pontiac, which is unlike the US version-year are all 55 Chevy underneath-mine has a 265/3spd already in it(seized).

Look very carefully at the way the 265 is installed now. They made a front cradle or transverse bracket for the inline six cylinder that mounted the same way. Find or fabricate a duplicate to the one for the six.

Take a pattern of the bolt pattern from the bell housing of your stick shift from the car.

Transfer the bolt pattern that attaches the bell housing to the back of the engine onto a sheet of 1/8" steel or 1/4" aluminum and drill those holes INCLUDING THE DOWEL PIN HOLES through your plate. The plate should be wide enough to duplicate the bell housing and the brackets that attach it to the frame of the car. OR!! You can buy a mid plate from several different chassis builders.

You need this mid-plate because the aluminum case that contains your 700R4 isn't strong enough to support the back of the six cylinder engine without it if you mount the six like the V8 is mounted in the front!

The final part is the transmission crossmember! You should do this piece LAST because you need to have the exhaust run so you can build around it too. These cars had NO transmission crossmember for the reason I explained in my earlier post. Depending on how experienced you are in fabrication, this can be an intricate piece or very simple and plain. On my 4banger project I went simple. It runs an open header and the car is very light, so it only needed to be a heavy wall piece of 1" tubing and three small sections of 2 1/2" angle. You're only seeking to prevent the transmission case from flexing too much and cracking in critical places.

It's really only five attachment points and if you have the front cradle mount and a store bought mid-plate, you can probably accomplish the whole installation in a weekend. I have knocked this same installation out in a long day using an engine hoist, a bunch of good jack stands, and hand tools. I welded the mounting tabs on the mid-plate and notched the bolt holes for the biscuit mounts. You can eliminate the welder if you bolt on those mounting tabs. Takes a little longer though.

This set-up duplicates the system used on the best race cars in the world and you use factory style engine and transmission isolation mounts.

EDIT: This set-up also allows you to avoid steering linkage, exhaust, and probably cooling system interference problems!!

You could look at Speedway # 916-18956 motor mounts for the rear.
There are 4 bolt holes on the front of the engine that could be used for fabricating front mounts that may reach the stock mounts.
At least, that is what I'm considering for a project I have.

I have been told that if you use front mounts, you have to use bellhousing mounts.
If you use a tailshaft mount, you have to use side mounts.

Will Willis

You are correct!! But If you hang a late model aluminum housing automatic off the back of a bellhousing mounted setup, you should use a lightweight crossmember to prevent extra stress on the tail housing and transmission case!! We used this setup on 1,500 hp race cars and 100 horsepower lightweight street cars both. I like this better for long, inline engine setups too!!

I have a nice set on my 292 that I had made. If you send me an email I can send pictures with measurements. Donut mounts. They put a 1/4" plate on drivers side to even them out. Do yourself a favor and look into electric power steering. All the big boys are using it. Easy to install and no mess. Cut a piece out of the column and hook it up.

Hey man, email is wrightsutomotiveinc@gmail.com. It looks like this thing will fit physically, according to the loose valve cover I had lying around! Mick53-is there P/s interference when using an aftermarket setup or are you talking about a hassle in general with p/s?

Sorry, wrightautomotiveinc@gmail.com

I bought my 292 mounts from Chassis Eng. for my 53 3100 pickup reference invoice #44948 12-6=16

Should be in your email. If not let me know.

Got the pics, looks like you have side mounts set up nicely. I'm wondering if a standard sbc mounting kit would work in tandem with something like Tom Lowe's adapter plate for the passenger side mounting.

Be careful not to over constrain things. As the engine and transmission heat up they will expand at different rate than the chassis - things have to be able to move, or something will break.