You're getting too much gas.
If you prime the carb with a ton of gas in both primary and secondaries and blip the throttle you'll get bogging and popping (fire!) at the carb.
Don't try to run it like this.
You need to rebuild the carb There is a $50 kit you can get at your local auto parts store and a special cleaner (solvent). It's really messy and smells up the house with gas so best outdoors or the garage with the door up.
Best to pick up a cheap rebuild book especially for your carb with clear photos of the process.
Makes it a whole lot easier to put it back together as well as tips on making it perform better by changing the jets and metering rods, springs etc.
It's not worth paying for a rebuild. If you don't want to attempt your own rebuild, I'd just buy a cheap Edelbrock Performer series carb on eBay (if you can find one new in the box). NEW, not "was working when pulled of the car..."Otherwise you'll be rebuilding that one too.
cause the lifters are not pumped up?
572
no
the biggest crate motor GM chevy makes is a 572 not a 502
275 h.p.
yes.
Over 210
no. check with a warehousing distributor such as Scoggin-Dickey or similar for the crate motor that best suits your needs.
The Chevy Crate engine is an engine that is custom built. They usually have more power and are made from the original motor but bored out and modified.
yes
Oreilly auto parts. Can order you a new twin turbo motor in the crate
possible motor mount problem, when you turn the steering wheel- the wheels line up at a differant height and if the motor mount is totally shot then this cause the motor to bind with the tranny and or front axels depending on the car