My buddy just picked up a 55 chevy,350 smallblock with a turbo 400, it has the stock forward motor mounts and a cross member/****** mount back on the tail of the 400,he has been told the span is to much and needs a bellhousing mount or the engine mounts need to be moved back? is this a fact?......thanks jim
Side mounts for the engine. Most set-ups like the one your friend has will crack the transmission case.
What Slammed said. The front mounts don't provide enough support when used with a center, single-point transmission mount. The stock 55 had two ears on the frame to mount the ******. Chevy fixed this in 58. You can weld them in or bolt them in.
yup, that's a fact. Something like this should work, there are several vendors selling them http://www.speedwaymotors.com/1955-57-Chevy-Engine-Block-Side-Mount-Kit,1177.html
The Tri-Five vendors also sell a kit to add bellhousing mounts to later automatics; easier to just add that (as long as the frame horn mounts have'nt been removed). Butch/56sedandelivery.
Might be easier, but it looks kinda hokey.... The side mounts/rear trans mount has been used in Chevys since 58, it works real well.
With a center mount in the front and a center mount on the transmission, I don't see what keeps the engine from flopping around side to side and breaking distributor caps. Larry T
It isn't the span, it's the distance from the center line. The motor will try to twist under acceleration or deceleration. The transmission mount is on the center line and the front mounts are very close to the center line so they don't have any leverage. The mounts on the side of the bell housing prevented the motor from twisting.
I haven't seen any cracked bellhousings but used to see a lot of leaking front trans seals attributed to the flexing when they are mounted with the stock tri 5 biscuits in front and a rear trans mount. That crossmeber under the bellhousing was a huge part of the strength of the stock frame too and the frames tend to flex some when it's gone and the cab mounts eventually twist the frame rails out and let the cabs sag. That's the reason so many AD and Taskforce trucks look bent in the middle at the cowl.
I think we're talking about cars here, they don't have a crossmember under the bellhousing, only the trucks do. The car frames are box tube, the trucks are channel. They work quite differently.
Not all mount kits are created equal. The ones like speedway sells don't fit all tri five frames for some reason, there were two . So called East coast ,welded two piece main rails. and the so called one piece west coast frame , hydro formed main rails,(both were used in different ***embly plants however. ) Some mount kits like CPP are made to move the engine 3/4" of a inch forward for better firewall/HEI clearance. Yet another mount by Earl Wiilliams moves the engine to the right for better steering box/header room . Take your pick.
I agree with your comments about the rotational resistance, but I think you are underestimating the effect of the span load. Ray
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