LS swap quick questions on motor mounts

[blazed870]

I have a 70 C10 that I am going to be putting a Gen III 4.8 with the 4l60 out of a 2000 GMC truck. I want to use the stock manifolds as well. I have been looking at the Trans Adapt 4572 and the 4575 motor mount adapters.

1. Should I get the motor mount adapters for stock location or the ones that push the engine back 1"?

2. If I decide to use a F-body oil pan for more ground clearance, which motor mounts should I use?

3. Are these plates big enough that if I need to move the engine forward or back a little, I will be able to drill out new holes?

Thanks

Mickey