Are there different engine mounting brackets??

[454HO]

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.