Thread: Motor mounts not lining up

Tweet

IMAG0646.jpgIMAG0647.jpgIMAG0638.jpg]
Hi everyone,
I am dropping my new 350 in my 1986 pickup, and the engine mounts are not lining up.
The engine is a 1989 Gen. 1 Small Block 350 (Casting # 624) out of a 1986 1 ton 2wd. The engine-side motor mounts are out of that truck.
This truck is a 1986 1/2 ton GMC High Sierra 4wd. The engine I took out of this truck was a 70's #010 casting 350 block with identical mounts.
The frame-side motor mounts are new from Autozone, and installed in the only bolt holes they can be. They are identical in size to the mounts I took off. The mounts have 4 bolt holes with 3 bolts.
I tried swapping what side of the engine the mounts are bolted to, but that made no difference. I tried loosening bolts on the mounts to let them slide around, but still too far off.
In the picture, the passenger side mount is together (it has the through-bolt in it), and you can see how far off the driver side is. I've tried jacking the engine in every direction. There is no way that bolt is going to go in. What am I doing wrong?
Thanks!

The only possibility I can think of is that the engine side portion of the mounts are different enough from the ones you originally had on the truck to make them not fit. A sbc is a sbc, and the holes are no different from one to the other (Unless you get into the LS stuff), so it has to be the mounts that came bolted to the block.

Do you have the entire old mount setup that was on your truck originally? If so, put that whole deal on and it has to fit. GM probably used a different engine portion to work with the later frame configuration.

Don

I'd say the motor mounts on the crossmember need to either be turned around or swapped side to side....Match them with the old mounts, if you didn't do a lot of super cleaning and painting on the crossmember you should be able so see where the original mounts were bolted on....

You can remove the mounts from the frame. put the bolts thru the mounts and set it back in as an assembly. You will then see what is going on. After you see whats wrong and what you need to do pull the assembly back out and corect the problem

Napa lists different number mounts between the two year and engines
They show part # 6021179 for the 86 350 and part number #6021581 for the 89.
The pictures of the two different mounts are very close in appearence.
On another note I would turn your bolts that mount the mount to the frame around so that you don't have the end of the bolts sticking up in your way.

If the assembled side is all snugged up and the other side is snugged to the frame and block "loosen everything" leaving your thru bolt on that side. Use a draw pin or long punch and start wiggling the unattached side. You will be surprised to see what a little slop will get you.

Thanks everyone for the replies.
@itoldyouso - I do not have the original motor mounts, I sold them with the original block. They looked identical, but then again the holes could have been a quarter inch off and I wouldn'tve noticed.

@dave severson - I tried swapping the engine-side and frame-side mounts in every possible combination. And yes, the frame was wire brushed and painted.

@cffisher - that's about the only thing I didn't try, but it looked like to me that if I did that, it still wouldn't help. It looks like the mounts need to both move UP the frame about a half inch and then everything would be fine. I have considered drilling new holes, but thought I'd see what people say first.


@hworrell - I'll go to NAPA today. Everyone I have talked to says the mounts are the same for any small or big block engine, gas or diesel. They all are interchangeable. At least that's what I've been told. The problem I see, is the bolt pattern on the frame is still the same, so that mount is going to have the through-bolt hole in the middle of that bolt pattern. This would still make the engine not fit in there. If I got a different motor-side engine mount, I could see how it would work. The other thing, is the engine was an 1989 engine, but it came from a 1986 truck, and I am installing it into a 1986 truck. Only difference is it came from a 1 ton Chevy 2wd and its going into a 1/2 ton GMC 4wd.

@sfort - Tried that. Motor-side mounts AND frame-side mounts are loose on both sides, even in this picture.


Thanks everyone for the replies. I'm going to go to NAPA today and see if I can't get a different bracket, because there is no way this bracket will work. I honestly tried every suggestion in this thread. I was hoping someone ran into this problem before! I had a buddy who ran into this issue about a month ago, and he said he tried a (motor-side) mount from a 79 truck that was laying in the barn and it worked fine. Everyone else I've talked to said there is only one size mount.

they have a big and wide , and also , a tall and narrow

everything is not the same

You were posting while I was, making my post irrelevant.

Originally Posted by jerry clayton

they have a big and wide , and also , a tall and narrow
everything is not the same

Sounds like a clothing store at the mall!

Sorry, couldn't help myself!!

I just looked up my vin number and the truck came from the factory with a 5.0L 305. Would that make any difference?

Nope, they are the same.

Don

So I was looking at these frame mounts, and maybe I have them in (or one in) upside down. If you turn it one way, the tab is higher on the back than in the front. If you turn it the other way, the tab is on the bottom half and on the back its on the top half. Maybe one is in backwards. Which way do they go? I don't have pictures of before, and I cant find much online. Thanks.

Go back to post 4

Ok now that I'm really looking at it, it has to have the top tab high towards the bottom and low towards the back. It matches the frame's angle. Which is the way I originally had it.....
IMAG0654.jpg