Planning out my 70 Challenger here. Its a 6-cyl car originally, so the K-member will have to come out. I have a V8 one and mounts already handy, but i gets to thinkin'...

If i were to shave off the engine mount stuff on my 6-cyl K-member and go with an aluminum engine plate instead, would i be saving or gaining weight? Does the K-member mounting pads + mounts + insulators add up to more than just a plate?

If its about the same i'd just stick with stock and swap K-members, but if there is even 10lbs in there it might be worth going with the plate. I'm assuming there are other benefits to switching to an engine plate as well...???

Weight is going to be a VERY important theme in this build. Light weight and simplicity. Yet i dont have much money for fancy stuff. I'm willing to spend time on the details.

More or less the same. Maybe a few pounds saved.
The stock K-member mounting pads, steel engine mounts, insulators along with the hardware bolts, washers and nuts will come out to be a little more in weight than a whole cross section aluminum plate, plate mounting pads welded onto the frame, engine/transmission limiters and all of that mounting hardware bolts, washers and nuts. Plus remember that you probably have to weld shut some spaces where the mounts were attached to the steering box mount on some cars.
You'll also have to shave the same difference off the water pump housing on the engine mounting surfaces to make up for the plates thickness.

I have used elephant ears to install B,RB and 426 hemi in Dusters and Demons, I would bet money that you will save around 18 to 23 lbs by using them, especially if you cut all the stock mounts off of the K member I have two motor plates in the shop now on motors, I'll bet money there is not 3 lbs more weight in them than the eelepahnt ears They can be trimmed down a bunch also Now, Get after it

Hmmmmmm......

A 'few pounds' to 23lbs... give or take. That sounds like a worthy endeavor.

I'm assuming the general simplicity ov the install and maintenance on the engine is a lot better with a plate or ears...???

Any downsides to doing this...???

If it's a street car you'll notice substantially more vibration as it's a solid mount. If just a race car go for it.

what about a ploy mounted engine plate to keep the vibrations down?

I didn't notice any difference from solid motor mounts to a plate.

I've definitely heard both sides ov the fence on solid mounts/plate for the street. Some say its horrid, others dont notice. I figure its got a LOT to do with how balanced your engine is. With the usual Mopar factory build, or typical rebuild (to stock specs), yeah... i could see how people get upset. Mopar engines are awful... i think i've had 4-5 smooth running engines out ov probably 25 i've owned. But if you built one right... it should run smooth and cut down on the chassis violence. Ford modular guys run solid mounts and never complain. Those engines run like glass...

I'm basically building a road race car i can daily drive. NVH doesn't scare me, in fact, its half the reason why i went from GM (Buicks) to Mopars.


Also, what is an engine limiter...???

A engine limiter stops or reduces the fore/aft movement of the engine.

If this was my car..I'd cut the mounts off of the stock 6 cyl K and use a plate.The plate makes engine removal/installation so much easier.

So much more benefit from motor plate

A good unanimous chorus in here... rare for my questions. Sounds like i have a new plan. Kind ov a shame to cut up an original SUPER-rare 6cyl E-body K-member though... It IS coming out before the swap anyways, to bolt up my new suspension and stiffen the K... maybe i'll just cut up the V8 one i have kicking around instead.

I like light. I like simple. And i like easy maintenance.

Where does the engine limiter go, and how much extra weight does that add? Funny i've never heard ov these before...

Ya, like there's a line a mile long waiting for that 6 cylinder k member. off the mounts.

I'm not real happy with the aluminum plates in use. The danger is bending, and if 5/16" steel is enough, an aluminum plate has to be 15/16" for the same rigidity.