ok, in '85 I believe the standard engine was a TBI 305. That's a chevy "small block.. That means any Chevy small block from 305 to 400 will bolt into the hole.
I would recommend the 350 cubic inch crate motor in the 300 - 325 HP range. That is an extremely reliable motor and will give you a much faster car then the 305. They are also easy on fuel. Your only issue there is you will have to put TBI intake system on it or disable the ECM.
As to transmission, it really depends on what the car had in it to begin with. If it was a stick, then no problem, but if it was an auto, you will have to find a donor car to pull the parts for the swap. Lots-O-trouble.
Order a crate motor from GM Performance. They come in HP ratings from mild to wild depending on how much you want to spend. Your car may have originally be a V-6 but no matter a V-8 was available and I'm betting the frame is drilled so you can move the 6's motor mounts to accommodate the 8. The motor mounts should be the same. All the parts you will need are from GM but save yourself some money and try to buy through NAPA. Cheaper and I've never been disappointed with a NAPA replacement part in 30 years of restoring old iron.
After getting yourself a project car in the form of an mid 1980's Camaro Z28 as likely it may have came with a carburated 305 as it now is a rolling chassis. If you really want a dependable daily driver a ZZ crate engine from GM or performance shops would be enough and be pretty dependable. You could be doing serious transmission tunnel surgery just to get the T56 six speed manual to fit as American drivetrain would gladly recommend a five speed manual with little modifications to the transmission tunnel.
They have swap kits.
http://www.thirdgen.org/forums/ltx-lsx/4...
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