1955 vs 1958 Motor Mounts

[olskool68]

Howdy gentelmen. First post, long time follower. My son and I bought a '58 Fleetside as our project for his first truck a few months back. We've got the front clip off and getting ready to hoist out the 235. He wants to keep the old six in it. I got to looking at the number on the block, 3836233. Number indicates that its a 1955 engine.

My question is, what sort of mounts should I be looking for? Whats the difference between the 55-57 and 58-59 mounts? I see plenty of 55-57 mounts (studs and rubber donuts) available but nothing for the 58-59. Thanks folks.

[Maximus]

Im not 100% sure of this but I am thinking they are the same.
The front frames of the 55-59 were identical so the only changes in mounts I would think would be changes in motors. Looking at a vendors site, Classicparts.com, they have a 'V8 converison mount' from 55-59, and replacement rubber bushings from 55-59.

Replacement Bushings Link

Someone correct me if im wrong, but a 55-57 mount will work?
you may want to simply call ClassicParts and ask them, because that link may be for the entire motor mount set (you can buy the rubber bushings for $2.50 a piece so I don't see why they would be $50/set.

[olskool68]

Thanks, Maximus. I have seen where the rubber bushings are the same for those 5 years on several supplier websites. And I've seen the V8 mounts. But I was wondering if the studs themselves were any different. I can't tell for sure yet, but it looks like one of my mounts may be bent. If all I have to replace is the rubber bushings, then I'm golden.

[TX58]

Are you looking for front or rear mounts? I bought the complete front set from classic. It's a bit pricey but mine were rusted thin. The rears are just the rubber parts, have to reuse the metal parts
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[_Ogre]

olskool
realistically, the studs only support the front of the motor, the rear mounts absorb all the torque.
i don't see why threaded rod with nylock nuts wouldn't work.
if the v8 studs are the same (i'm thinking they are) i might have one for you. pm me.

if your changing the trans over to a rear mount, don't use the front stud mounts

[OrrieG]

They are the same. I had to fab the frame bracket but used mounts from an unknown engine and the donuts and parts from the 55-57. No need to spend money on expensive aftermarket parts if you have NAPA store close buy, I got mine from them. I also have used the donuts for other mounting applications, if I remember right they are about $7 for a pair. If you want I can get the PN and post them. The nice thing about using the factory or replacement rods is they have the expanded necks that catch the fender type washers so the only nuts are on the top and bottom. I used self locking nuts on mine. Back is supported from the rear th350 transmission/transfercase mount. I have always had a cable to the frame on the drivers side to limit engine movement. On a 4wd to much movement leads to broken transmission cases. Here are photos of my engine mount and side restraint bracket

[_Ogre]

orrieg, the problem i see with your mounts is the original heavy mount was on the bell housing, with light mounts up front.
modern sbc have heavy side mounts with a light mount on the trans.
you have used both light mounts and no heavy mount.
the heavy mount is to resist torque, the light mount resist side to side.

i had a truck set up like your, i couldn't keep exhaust donuts in it.
i had a friend stand on the brake and stomp it forward and reverse, i was shocked how much the motor moved.
then i made these (in pic) and that stopped all movement, i cut them out when i did the mustII.

since you have side mount bosses on your motor, i'd fab a set of these.
they use a 68 truck mount and weld to the frame.
i'd send you these but you did a frame swap if i'm correct.

[JumboAMONGus]

v8- 6cylinder front studs are difrent i have both one is longer then the other and the mount that bolts to the engine block is a difrent angle i have a set for a 6 cylinder somewhere in my garage complete and a set for v8 when i switched

[olskool68]

Thanks for all the help guys.

Hey OrrieG, i'd much appreciate that part number if you can dig it up.

Jumbo, I'll go take a closer look tonight. If I needed those studs, would u mind parting with them?

The studs sure do look mighty alike. I'm hoping mine are fine. Another thing brought up is the rear mount...so according to the block number, this was mated with a powerglide in its original life. Would the rear mount be any different vs the one it has now? I believe the tranny sitting in there now is the original 3 speed.

[dwcsr]

Originally Posted by olskool68

Howdy gentelmen. First post, long time follower. My son and I bought a '58 Fleetside as our project for his first truck a few months back. We've got the front clip off and getting ready to hoist out the 235. He wants to keep the old six in it. I got to looking at the number on the block, 3836233. Number indicates that its a 1955 engine.

My question is, what sort of mounts should I be looking for? Whats the difference between the 55-57 and 58-59 mounts? I see plenty of 55-57 mounts (studs and rubber donuts) available but nothing for the 58-59. Thanks folks.

On 55.2-57 and 58-59 the front mounts are the same for 6 cylinders. 58 59 also had sides mount midway on the block so it could be used in a car application. 60 up used a center mount like the 53 6 cylinder and had no provision for a mount that bolted to the front sides like 55-59. 58 up also was drilled for hydraulics on every block not just power-glide blocks. If I were rebuilding a motor I would certainly go for a 58 or 59 block.

[JumboAMONGus]

on my motor mounts i have two sizes of the front long bolts the 6 cylinders sat higher so the space between the top donut mount and bottom is wider v8 is like 2 1/4 inch and 6 cylinders are like 3 to 3 1/2 inches ,, and the brackets on the frame were the same but the bracket on the motor itself were diffrent angles on the holes drilled the 6 cylinder ones wouldnt bolt to a 57 283 ,, you can redrill them but for the rubber donuts there the same

[JumboAMONGus]

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