Can you use this style of motor mount plate?

[2drx4]

I'm curious if these mount plates will work: https://www.ebay.com/itm/2549049111...d=link&campid=5335822911&toolid=20001&mkevt=1

(let me know if that link won't work)

The ad says they're for a 73-98 GM truck or "other cars that use the clam shell" mount. Are all the SBC clam shells the same after 73 (or 75 I think actually)? I think they changed again in 88? Some searching seemed to indicate they are, or maybe not. And you can't trust a sketchy eBay seller to be right...

Since my car has the Olds engine in it I'd rather just buy a mount plate that has the "clamshell" integrated into it, since I don't believe what's on my engine can be used.


ICT billet also sells this kit: https://www.ictbillet.com/1975-1987...steel-clamshell-bracket-motor-conversion.html

Which says it positions the engine exactly as a SBC was, or so that the transmission is in the exact same place. Reading between the lines I believe this means that it's the same as the 1" set back mounts if you use the factory clamshells. I'm not sure if ICT Billet ships to me, I'd lean towards just buying their product if they do, assuming that's the right one.

I already ordered a 302-1 style oil pan.

 

[ELCAM]

What I do know is that the truck mounts are like 1/2" longer ( Measured from where the bracket mounts on the engine block to the through bolt.) than the car mounts that used the clamshell mount on the frame.

I have a set of both car and truck mount engine side brackets around here somewhere if you need a picture.

 

[2drx4]

What I do know is that the truck mounts are like 1/2" longer ( Measured from where the bracket mounts on the engine block to the through bolt.) than the car mounts that used the clamshell mount on the frame.

I have a set of both car and truck mount engine side brackets around here somewhere if you need a picture.

Oh. A picture would be great.

In one of the other threads a poster complained his mounts wouldn't sit down right when he went to bolt it in the car, and he wound installing the mounts higher on the crossmember (drilled new holes). If it's a 1/2" on each side there, then I could see that being what would have caused his problems. He bought new clamshells and generic relocation plates to do the install and maybe got the wrong clamshells.

But, basically the answer is no, they're not the same.

So, what does the ICT Billet ones fit then? A car or a truck?

 

[2drx4]

Hooker sells these: https://www.holley.com/products/eng...8_gm_g-body_ls_swap_components/parts/12643HKR

Which I'd say puts to rest any doubt, you can tell they bracket does not stick out as far on them as the eBay sketchy seller ones.

Unfortunately the Hooker ones are over $200 US. Rather rich for what they are. Also I think they updated the design to use countersunk hardware (not pictured), which is a massive pet peeve of mine if there is no need for it, and if one hole needs it for clearance only that hole should be countersunk. But that's another topic.

I have no idea where I'm going to find a set of factory SBC clamshells. There is not an abundance of cars that might have them around here.


Edit, man are the welds on that one bracket horrible. I'd be pissed off to receive that crap for any price more than free.


2nd edit, I emailed ICT Billet about their mounts. I don't know if I'll get a reply.

 

[2drx4]

Okay, other option. UMI Performance 90058 HD engine mounts:

1978-1988 GM G-Body SBC Engine Mount Clamshells - UMI Performance Inc.

The P/N 90058 heavy duty engine mounts for GM G-body cars takes the place of the heavy factory clamshell mount.

www.umiperformance.com

They say they work with factory rubber mounts, solid mounts are not required. If I buy these I can run any of the generic flat plate adapters. Which I still think is a stupid solution, but everyone is doing it so it can't be that bad.

I've got them in my Summit cart right now. Hit buy?

 

[ELCAM]

Here is a side view. L to R UMI, factory Car and factory Truck,

 

[2drx4]

Here is a side view. L to R UMI, factory Car and factory Truck,

Awesome! Thanks so much.

I'll order the UMI mounts.