I've been looking for a vortec 350 engine for a while to swap out in the Firebird because it's a roller block. My dilemma is that I found one that "needs bearings" pretty cheap and I'm wondering if it's worth buying and rebuilding or not? What are the chances the block would have damage based on what you guys have seen? The crank and a rebuild kit isn't too much money but once I get into machine work the price goes way up.

If I pay more for another engine it doesn't guarantee that I won't find bad bearings in those once I open it up since most are pulled already out of the vehicle and not running. Any engine I'd swap I'd open up anyways just to be safe and check over before throwing in the bird.

 

"Needs bearings" has quite a range of possibilities. If it had rod knock your into machine work on the crank as a min. If it was just lower than normal oil pressure maybe u can replace the bearings and go. When labor was cheap re-ring and re-bearng overhauls were the norm by 100K mi and most of your service manuals still instruct the full engine overhaul today.

I like to measure compression if possible and a leakdown test also if possible. This tells u the health of the cyls - vlvs and rings.

Ya know most boneyards will guarantee an used engine and some will even start it for you.

If u really need a budget motor i would shop the auto parts stores for an ATK rebuild. The small block chevy is as cheap as it gets and ATK has one of the better reputations. They also have performance engines now but u just want to cheap it on a budget.

 

If all you are looking for is a block and don't care about the rotating assembly, chances are good it's fine if it's knocking.

I've only ever seen one motor knock that destroyed the block because a rod broke and smashed the last 1" out of one of the cylinder walls.

 

If you're already buying a new crank and rebuild kit, then you've pretty much covered everything except machine work like decking and honing the cylinders.

 

I will say my concern would be a spun main bearing. Ask if you can pop the caps and if they're spun leave it be. Getting an align hone/bore can be pricey.

If the rods are toast consider tossing a crank in it/machining the bearings and being done with it.

As said check the bores. There's a lot of junk out there people try to push off as servicable. Definitely the peril of Craigslist and what have you.

 

Well I bought the motor. Spun main bearing. The machine shop my uncle works for told me it's common on the vortec engines and that Federal-Mogul made an oversize bearing for it but their not sure if it's still available. Just hoping I didn't get into a money pit here.