This came out of a 58 Pontiac wagon. Its locked up. I don't know what it is or if it's anything more than scrap.
Welp, it certainly looks like a 58 Pontiac [370] engine to me. I run one in my 34 ford and love it! If yours has been sitting in the weather for awhile it might never come un-stuck but I'd have to give it a try by soaking it in a transmission fluid/acetone mix after removing the heads. Who knows? Maybe it's a low mileage engine. You'll know as soon as you yank the heads and feel for a ridge at the top of the cylinders.
The trans should be a Jetaway. It's a 4 speed dual coupling trans. It's not the more rugged older dual range hydro and it's not a roto hydramatic. Trans is not easily rebuilt and can't really be modified for performane either. However IMO they are a decent trans if working and in good shape. Many don't agree with my opinion lol.
I've had several 57's [same as '58 trans] with the automatic trans. Never cared for the way they function. Gear ratios are spaced so the engine drops a BUNCH of rpms when shifting. I've switched to Muncie 4 speeds with mine.
That's just my opinion. Pretty much scrap. If you can find a '58-60 Pontiac with manual trans you can use the clutch/flywheel/starter/bellhousing to put a modern manual trans behind the engine. Sometimes hard to find but anything from a T-5, 5 speed to an old 58-up original 3 speed. The photo shows a 389/Borg Warner T-85 3 speed from a 1959 Ambulance. I used the entire stick setup in my 34 behind a 370 Pontiac engine. I substituted a Muncie 4 speed in place of the 3 speed....
That transmission works best with a 2 series rear end ratio or even the 3:08. They have a 3.97:1 first gear but have no stator so these no multiplying torque like the Turbo 400. I had one behind a very strong 462 and it didn't miss a beat. This same motor cracked the case of the Turbo 400 that replaced the hydro. You can get them to shift later by installing a governor for the 421 tri power. That's what I did. When racing I just put it in L and left it there. The trans would shift at 5200 into second and 5400 into third.. 5000 into fourth.. What I liked about the hydro was the gas mileage. The transmission would couple like a stick shift in third and fourth.. Dropping the hammer at 15 mph with a big motor and having that trans go into first the car would go crazy..
I always liked that 370 engine and never understood why it didn't become more popular... I think they came with a forged crank and rods?
My uncle had a 58 Chieftain HT with the 370 Tri-Power. He never had a transmission problem and he did not baby it! When the body rusted away he gave me the car and the 370 was rebuilt and hopped up a little and we ran it in a modified pulling tractor for a couple seasons until we had to go to a 427 L-88 Chevy to keep up in the horsepower race. When it was took out of the tractor we oiled the cylinders real well and it sat from the early 70's until about 95 when I put it in my 54 Olds with a 59 Pontiac auto trans. Got it running and then it got put on the back burner where it still is. I am getting caught up on some of my other projects so either the Olds is next or it is going down the road.
You have a couple of hundred bucks there in the oil pan, gusher tubes, exhaust manifolds, oil pump core & Vibration dampener. Crank will fit a '57, so will heads.