Transmission mount for a drag car.

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MOPARMAGA

MOPARMAGA

" The other hard member"
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Before I go buying something I won't use, what do you guys use for trans mounts.
I was thinking polyurethane, but just wanted to check with the more seasoned racers.
Should be low 10's, engine plate, big block auto, Dana, decent suspension
 
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I'm using elephant ears, so there won't be much movement, and I don't want the case binding. Using a stock rubber trans mount.
I did have to modify the trans crossmember when I changed from a pushbutton trans to a late model.
 
33IMP said:
I'm using elephant ears, so there won't be much movement, and I don't want the case binding. Using a stock rubber trans mount.
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Elephant ears on the engine ?
 
Are you also using a mid-plate?
 
Probably. But like I said, I don't think the engine/trans will move much, but I don't want to bind the trans case.
My rubber one has lasted for 20 years, so has the trans. 11 second car. My 9 second car uses a front plate and a mid plate. The trans crossmember is decorative. Rubber there too.
 
I'm running a stroker 416 SBM with a front plate & mid plate, I have a poly transmission mount with no problems.
 
MOPARMAGA said:
Me? No mid plate
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I'm no engineer but if I were using a front engine plate, I would also use a mid plate. Think about the distance and weight hanging between a front plate and the transmission mount. With factory mounts on the side of the engine, it's more of the engine weight being supported on the mounts. That being said, I would bet it has been done plenty of times. It may not be an issue at all. People have gotten away with all sorts of things on drag cars at local tracks. This is just my opinion.
 
MOPARMAGA said:
This maybe a dumb question but does a spool mount work on a 70 a body, mine has a biscuit type & I don't see how it would work
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A spool mount k-frame would be needed if you're talking about spool type engine mounts. I think that started in 73.
I just checked my 73 Dart Sport transmission mount. It does look like a spool type mount.
 
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To use a spool mount, you have to change the cross member that the mount is attached to.
 
tinman2 said:
I'm no engineer but if I were using a front engine plate, I would also use a mid plate. Think about the distance and weight hanging between a front plate and the transmission mount. With factory mounts on the side of the engine, it's more of the engine weight being supported on the mounts. That being said, I would bet it has been done plenty of times. It may not be an issue at all. People have gotten away with all sorts of things on drag cars at local tracks. This is just my opinion.
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Well if any bell housing bolts came loose that could be very bad. Something would break
 
tinman2 said:
A spool mount k-frame would be needed if you're talking about spool type engine mounts. I think that started in 73.
I just checked my 73 Dart Sport transmission mount. It does look like a spool type mount.
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I was just asking about the transmission mount.
The 70-72 are different than 73-76
 
I was just looking over at moparts, man a mid plate is much more simple than I had imagined. I will go ahead and make or buy 1 & a flex plate spacer.
Then use my biscuit poly on the c-member.
 
Running plates, it would seem nothing would be moving much at all. Especially with a mid plate. A pretty well respected tranny guy told me no poly trans mounts. They can break tailshaft housings when used with stock mounts. Motor moves, stiff trans mount doesn’t. That being said, I have run a poly one since I finished the car in 2009. Figure if it was going to break the housing it would have already. I’m was also the designated guy to carry a spare 727 tailshaft housing in case anyone in the group has an emergency! They’re going to have to find some other schmuck to hump it around now that I’m running a 904!!! :):):)
 
furrystump said:
Running plates, it would seem nothing would be moving much at all. Especially with a mid plate. A pretty well respected tranny guy told me no poly trans mounts. They can break tailshaft housings when used with stock mounts. Motor moves, stiff trans mount doesn’t. That being said, I have run a poly one since I finished the car in 2009. Figure if it was going to break the housing it would have already. I’m was also the designated guy to carry a spare 727 tailshaft housing in case anyone in the group has an emergency! They’re going to have to find some other schmuck to hump it around now that I’m running a 904!!! :):):)
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I heard the same about a Poly trans mount with rubber engine mounts. Another reason I run a rubber trans mount.
 
I have run a Poly trans mount for years, in several cars all with different combinations. drag car with a solid divers spool mount, filled passenger spool mount. drag car motor plate with small poly bushings. rubber ( new ) engine mounts and the poly trans. never had an issue. I can see how a worn soft rubber mount could add extra stress to the trans mount. never worried about it since the early trans mounts have one tiny bolt holding it in place. its more likely to break than a case. now if your talking the later spool style trans mount, I might be more concerned.
 
With solid engine mounting, doesn't chassis flex come into play with hard launches as far as the mounting? Like a bar vs cage deal? I agree with 331MP that a fresh rubber trans mount is easier on the trans for most of the moderate applications.
 
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