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pros and cons of a motor mounting plate?

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15K views 3 replies 4 participants last post by  techinspector1  
#1 ·
i am about to put a sbc into my 54 chevy. i have been looking at different motor mounts and then a friend of mine suggested that i use an motor plate. ok so here is my question ....is using a motor plate on the front of an engine hard on the bell-housing of the transmission? do i need to use an mid-plate in conjunction with the front plate. i will be building this plate myself out of 1/4 inch aluminum so any suggestions would be greatly appreciated thanks again
 
#2 ·
Yes, without a mid plate, it is very hard on the bell housing. Just too great a distance between mounts.......By the time you make both plates and mount them, it would be easier to make or buy side mounts and a rear cross member in my opinion.
 
#3 ·
Like Poncho has said, you have to have a mid plate, or at least the mid mount batwings some of the circle track guys use, to support the rear of the engine. It will be too great a distance between the front of the motor and just a regular transmission tail shaft mount.

Pro's are it frees up a lot of header space, provides a very stable place for accessory mounting, and takes large HP loads off the side of the block and puts it into the much more solid front bulkhead of the block.

Con's are the needed mid plate, you have to watch the plate for cracks over time(aluminum fatigue), and you will need to fab up a lateral link support to keep the engine from shifting forward or backward under acceleration and braking, which will flex the plate and lead to cracking. Most use a hiem joint link(rod ends and threaded tube) from one of the old motor mount bolt locations on the block back to the frame near the drivers feet. Very similar to a diagonal link on a set of ladder bars or 4-link rear.
 
#4 ·
If this is a street driver, you're gonna hate motor plates for the engine vibes that will be transferred to the car. If you do it, mount the plates in rubber mounts. The cleanest install is to use a tubular crossmember with stock motor mounts for the engine and a tubular crossmember with stock trans mount for the transmission install.
Here's the engine crossmember....
http://www.speedwaymotors.com/S-B-B-B-or-90-Degree-V6-Chevy-Crossmember-Mount,3273.html
Here are the rubber motor mounts to use with it....strongly suggest using rubber rather than poly....
http://www.speedwaymotors.com/Small-Block-Chevy-Rubber-Motor-Mounts,7959.html

Here's the trans mount....
http://www.speedwaymotors.com/Tubular-Transmission-Mount-with-6-Inch-Drop,4356.html
Speedway makes these trans mounts with a 2", 4", 6" or 8" drop, so you can choose the best depth.