I just purchased a 1994 blazer k5 sport 5.7 350. I went to change my oil and it was thin and smelled like gas. The truck is burning gas like crazy and there is smoke coming out the tail pipe. The truck also smells like gasoline while running. I had a compression test done and everything checked out. He said it appears I have a bad ring. I want to know what is my best alternative to fixing the problem. New engine? Rebuild kit? New rings? What the cheapest effective alternative?

 

Changing the engine will not solve your problem. The problem lies in your fuel delivery system. Find out what's dumping the excessive gas, injectors or carb. and fix that. Change the oil after repair and drive, then you can determine if the engine needs work.

 

yea u are most likely getting too much fuel, a bad o2 sensor will do it, the bad rings dont help much either on the next oil change try using an engine oil cleaner, then use a half can of lucas oil, then go for a good boot on the hyway hammer on it once after it is hot to burn off the carbon and see if that clears it up.
the rings u think are bad may just be stuck and need a good cleaning then a blast to free things up, also use a little bit of fuel injector cleaner

 

I don't think you should buy a new engine. but before that take the car to the mechanic and get the engine oil cleaned. and the rings might be dirty clean them off and try it should change.