Hello and thank you for your post. I am a master certified GM tech and can help you to resolve your issue.you are going to have to swap the brackets from the old engine onto the new one.
Look for witness marks so you can tell which bracket was on top of which bracket.
Then you should eventually be able to figure out which ones go where.
There are three brackets. One bolts to the block and one bolts to the exhaust manifold. the other is like cradle for the old A/C. Will it work with out the A/C or is there a after market pump bracket I should get to simplify things? Is there some where I could get pictures of the original setup?
Just what I was looking for nice find. So where do I get p/n 14082318 rear support bracket? Dealership? All the part stores say they they dont sell mounting brackets?
I doubt that this bracket is available from GM any longer. I would check with salvage yards to see if they have any 85 vehicles back with a Chevy 350 , or 305 engine in them.
This set up was pretty common from the late 70s to the mid 80s when they switched over to serpentine belt set up.
After market companies may still offer a chrome bracket set up. I would look at JEGs catalog, or PAW.
GM s surplus, vintage part, can be accessed through vpartsinc.com . This is where GM sends all it outdated parts.
I just did a search in google for the part #14082318 and found a company called comp nine. ( compnine.com) they listed the part and also offer a better diagram of the brackets $14.92 is what they list the part for.
I hope this helps, let me know if you need more information.