Hey, I just bought a 1994 chevy 2500 with a 350.
I'm relatively new to mechanical work. The only experience i have is repairing small engines and basic car maintenance.

The guy said all it needed was paint and tires. Test drove it and it rain great.
Upon further inspection of the engine (which supposedly is a crate dropped in 8 months ago) I noticed that the internals were coated with a thick black "varnish" is that the right word? The man who owned it clearly neglected to change the oil on time. I have seen a well maintained engine, it's almost as if you were looking at a new engine inside the oil cap.

I've been considering an engine flush such as seafoam, auto rx, and an old mechanic even said transmission fluid with oil mix.

What are your opinions on using an engine flush?
I was told that on a high mileage engine, it wouldn't be a good idea because the sludge actually helps the seals. Problem is im not sure if the guy lied about the crate engine or not. It is evident he didnt take care of it. BUT it still runs great.

what can i do to clean it up a bit and get it in tip top shape?

 

Personally, I'd run two can's of seafoam through it, then let it get up to temperature. From there I'd find an empty road, and drop it into first and run her up about 4500rpms for 15-20 seconds at a time. Do that three or four times. Then go through a series of hard starts allowing the transmission to shift hard and quick and revving it to the limit.

It's amazing how much **** can be burned off by doing this. I actually fixed an idling problem and a stalling in reverse problem just by doing the steps above on my 98. Just be sure you allow the truck to get up to 190 degrees or wherever your thermostat opens up. Otherwise you could risk damaging something