About to start bending some tube for a buggy. Spec's are - 383 SBC, 700R4, Atlas 4.3, 60's Front and Rear, will be running tires in the 37-40" range, but designed to allow 44's.

My question is - Has anyone solid mounted a motor/tranny combo in a rig?

I have been thinking that using mounting plates similar to these http://www.chassisshop.com/npmp.html, would solve a bunch of packaging problems, and allow a neater header installation. Most high end performance vehicles use a solid mount system, drag cars, sprint cars, indy cars. I plan on using front, mid and rear mounts.

I am concerned that in a heavy impact the forces would be transferred to the motor/tranny combo and would break the tranny case. I don't think the SBC or the Atlas would be the weak link. I am aware of the vibration and other issues.

Actual experience preferred rather than hearsay, or butthole theorizing.

You should try a search, this has been discussed a lot.......opinions vary.

In the early 80s, I ran a drag car with no rubber in the mounting, suspension, etc. anywhere.

I broke lots of parts.

I haven't in a 4x4. I have in a circletrack car.
Because the motor is really strong, and the rest of the parts aren't as much so, the roundy-rounder had solid motor mounts, with only a slight bit of flex in the tranny mount. The motor mounts took all the real stress, the tranny mount just kept the tranny from flopping around up/down in the chassis.

I've also seen roundy-rounders with motor plates both ends, and no tranny mount at all--the tranny just hangs off the bellhousing. Not a great setup for a crawler, as our trannys/transfers are a lot heavier and longer, than roundy-round trannies.

In a full-tube chassis, I wouldn't expect any chassis flex at all... work things right, and you can make the engine block, tranny, transfer, or whatever, stressed members of the chassis... thereby increasing strength while reducing weight. :)

I don't know anybody who runs solid mounts in a vehicle that they have to spend more than three hours at a time, in. I'd think the vibration would drive you nuts.

i run solid mounts in the cruzah, motor and tcase

they are not bad at all...

after suffering a motor mount failure on my rigs maiden voyage (ripping oil filter, clutch line etc)...

I solid mounted my trans and engine.....

Vibrations have not been a problem other than a few loose bolts here and there that where easily cured with lock-tite...

Me or my passengers don't to notice any bad engine vibes... Some people will tell you that it will jar your teeth loose.... but I have found this not the case...

Having an Auto (torque converter) should help absorb the shocks to your driveline....

thanks guys,
my only experience has been in circle track and drag stuff. The SBC is strong enough that it is used in stressed and semi-stressed applications, so I am not too concerned with that, The Atlas is strong enough.

my concern would be the 700R4 but I know they are used in drag cars that see a LOT of load leaving the line.

I don't really want to guinea pig this myself, but I may head that way. The packaging, center of gravity, header neatness, and other advantages are starting to look pretty attractive.

I have seen motor plates that used a small poly interface at the tube connection to help with the vibe issues, but not quite an isolated mount. I think I saw them on Modified's running in the south about 10 years ago, will have to see what I can find.

I was thinking of having to machine my own rear mount. Shave 1/4" off the AA adapter and create a mounting plate that fits in there.

My engine and transmission are both solidly mounted to the frame. I have nothing negative to say about how it works, I really like it. I just built solid mounts for the normal engine mount and tranny mount. Motor plates would be the best way to do it, very trick.

CJ