I'm buying a 1997 vortec 350 that came out of a 3/4 ton truck. I did alot of reading, and couldn't find much info except that the heavy duty truck motors had 4-bolt mains and steel cranks.
What are the chances that this motor actually has a steel crank if it's a 4 bolt main block? I am hoping the crank is either a 532 or a 552.

I've torn down a ton of vortec engines. The big majority had 2-bolt main blocks and cast cranks. I've seen very few steel cranks, but that doesn't mean yours doesn't have one. Good luck, hope it works out for you.

I'm buying a 1997 vortec 350 that came out of a 3/4 ton truck. I did alot of reading, and couldn't find much info except that the heavy duty truck motors had 4-bolt mains and steel cranks.
What are the chances that this motor actually has a steel crank if it's a 4 bolt main block? I am hoping the crank is either a 532 or a 552.

I will tell you right now that they do exist I work at a GM dealer as a tech bought 2 core motors 1 with 8k on it tore it down as the complaint was engine knock. It was so funny I almost peed my pants, it was so funny so to make a long story short it had carbon on the tops of the pistons so much so that the pistons hit the deck but no damage. The engine had 4bolt mains a steel crank and get this powdered metal rods and it came out of a 3/4 ton truck. I had the parts guy check with the factory and they told him that they had so many lt1 rotating assy. there that they put them in the hd trucks
to use them up and this is not the first time I have seen this. back in 1988 I had GTA trans am that had an engine problem pulled the motor pulled the pan and it had 4 bolt mains so it can happen. I have no reason to lie about this after all the cores only cost me 100$ a good deal for gm's screw ups in our favor. good luck hope yours is a good one too.

Maybe here in Canada they don't do much with steel cranks but since the release of the one piece seal engines back in 1986 I have seen 1 steel crank.

Yea Rust, My vortec 4 bolt roller motor(out of a 98 2500 4x4 ex. cab had a cast crank. That truck would be a perfect candidate for a steel crank!!I also have another 4 bolt 1 piece out of a truck that had a cast unit in it..
Hulk
A forged crank has a flat spot with 2 parting lines???
Hulk

Nothing wrong with a cast factory crank in most of the combo's out there IMHO.
Cast has a thin parting line, forged is maybe 1/4" or so wide.

If you are running less than 500HP at 7000RPM on the street I would not be scared of the cast crank.

My engine core is a vortec from a 1997 railroad service truck. I don't know just how big the truck was but the block has 4 bolt mains. The crank was cast and the rods were PM.

Very low mile engine too, roughly 30,000 miles. It cleaned up reeeeeal easy. I guess the railroad wanted the truck back in service so bad they didn't want the low compression (must have been a head or head gasket problem) actually fixed, they paid for a new engine to be put in right away. The shortblock sat in the corner of the shop for a couple years before I answered an ad. The engine I was calling about was sold, "but we've got that one over there." All they knew was that it was from that RR truck they worked on a couple years ago and they sold the heads to some hotrodders. I bought the core for $100, pulled the pan and about wet my pants when I saw the 4 bolt mains. WOohoo!!!

you'd think the cores would be worth perhaps $100 in american money.
4 bolt mains and steel cranks as a bonus.

in production,, we did the austin independent school district bus's. the ones with the van type front end with a box rear section,, alot of them had steel cranks. not always,, but most of them. i'm thinking it was planned before hand with the school district somehow.