Are there different engine mounting brackets??
 

I'm wondering if there are different engine mounting brackets. I'm talking about the cup shaped piece that actually bolts to the engine block, not the clamshell rubber engine mount or the so called 'towers' that the clamshell bolts to. Wish I had a pic on the computer to help explain.

The reason I ask is I am trying to install a 2000 BB Vortec engine in my '86 short bed truck and it sits lower in the framerails than the BB engine in my old '77 did. It sits so low, the headers I have hit the top of the frame, whereas I had close to 1/2" of clearance in the other truck. Since I am using the same towers and new replacement rubber mounts, the only suspects are the engine brackets, the frame or perhaps the bosses on the engine block. Anyone have an idea what might be causing this? If not I will get a picture tomorrow to explain.

Re: Are there different engine mounting brackets??
 

Talking about these? I am pretty sure the SB and BB ones are the same. I used the same ones when I went from 350 to 454.

Re: Are there different engine mounting brackets??
 

There is a difference between 305 and 350 brackets, could possibly be the same deal. Not a difference in the actual engine brackets, but there is a plate that goes behind the 305 mounts(engine side) to be able to bolt a 350 in an originally 305 equipped truck. Ran into this problem with my truck. Originally came with a 305 and now has a 350 in it.

Re: Are there different engine mounting brackets??
 

Is this a 454 7.4L Vortec or a 496 8.1L Vortec ?

If it's an 8.1, it's a tall deck motor so that will affect your header placement. Also, I believe these have dual motor mount bosses for a new style mount and the traditional mounts so thats also something to check out. You could have the stands bolted to the wrong set of holes but I don't know how probable that is.

Re: Are there different engine mounting brackets??
 

The later engine may have different engine brackets. Try the ones off of the original engine that came out of your truck to see if they make a difference.

Re: Are there different engine mounting brackets??
 

On a 74 c20 I did an engine swap on, the towers could be moved to fit different engines. check to see if the cross member can allow the needed movement. if not get a drill.

Re: Are there different engine mounting brackets??
 

Yep, those are the ones. I was able to snap a quick pic. You can see by the green arrows that the rubber mounts are pushed way down. What I am wandering is if the dimension 'A' on these brackets is too short.

http://home.att.net/~gotdart/pictures/HPIM0023_8x6.jpg

Just eyeballing against another set of brackets off of my 77's 402, they look about 1/4" - 3/8" shorter. I really need to take them off to measure and be sure though.

And BTW, this is a Gen VI Vortec 7400 block.

Re: Are there different engine mounting brackets??
 

Worst case, you might be able to make a spacer plate and get some longer grade 8 bolts.

Re: Are there different engine mounting brackets??
 

Are these rubber auto parts store mounts ? They might have settled some...maybe a little too much. You could either make spacers or try some high quality polyurethane mounts.

Re: Are there different engine mounting brackets??
 

Brand new from Advance Auto.

Re: Are there different engine mounting brackets??
 

I have seen a few engines that have 1/2" spacers between the engine and the cups.

There is also a difference between 2wd and 4x4 engine mount cups as well, I had a heck of a time trying to bolt my engine back in when I converted to 4x4 till I figured that out.

Re: Are there different engine mounting brackets??
 

I finally got some time to work on the truck again yesterday. The new Vortec 454 is finally sitting in the frame correctly now. Here is what I found on the mounts.

First, I had 3 different engine mounts, or 'cups'. I could tell just by looking the cups on the Vortec were not as tall as the cups that were on the '77 big block that I parted out, or the cups on the '86 305 engine I was replacing. But I couldn't get a measurement without removing then.

So here are the three cups side by side. The left one is from the '77 long bed with original big block, center is from the '00 C3500 Vortec 7400, and the right one is from the '86 short bed with a 305.

http://home.att.net/~gotdart/truck/HPIM0138_8x6.JPG

The approximate measurement from the block mounting surface to the center of the engine mounting hole for these mounts are:
'00 Vortec - 2-1/8"
'77 454 - 2-5/8"
'86 305 - 2-3/4"

That is only half the story. I also discovered the rubber engine mounts for the 305 small block are different from the original big block mounts from my '77. Here is the picture, look at the lower monting holes on the right side of the pic.

http://home.att.net/~gotdart/truck/HPIM0134_8x6.JPG

You can see they are spaced closer together both in the horizontal and vertical dimension. This causes them to line up differently with the holes in the mount towers that are on the frame. Unfortunately I did not snap a picture of this.

I first tried using the 305 mounting cups since they were the tallest with the BB engine mounts. After much grunting and cussing trying to get it to line up, I gave up and swapped the cups for the 454 cups out of the '77. Then the motor literally just dropped into place!

:metal:

Here is the money shot.

http://home.att.net/~gotdart/truck/HPIM0144_8x6.JPG

I got the 1/2" clearance I was looking for! Yeeee Haaaahhh!!!

And here is the front shot showing both mounts. Notice I used poly bushings that are inserted into the original steel clamshells from the '77 truck. I plan on cleaning up the new small block mounts I bought and trying to exchange them for big block mounts.

http://home.att.net/~gotdart/truck/HPIM0153_8x6.JPG