If you sell it as is , just $150 or so .
Me , I'd make it run and then drive it , as it's a full pressure , seven main bearing high nickle content block GMC L O N G MOTOR , I honestly believe you'll be surprised and pleased with how much power it makes , not a V-8 but those are (yawn) belly buttons , anyone can have one .
Even when you're running it hard , it sips less fuel than any V-8 so consider that as fuel prices raise back up to $5.00 the Gallon next year .
If you tune it up and make it run well , you *might* find someone who needs it and will give you $300 ~ $500 for the whole shebang , fan to U-Joint , engine and tranny but , this is the small l o n g motor so even though it'll run rings around the wimpy Chevrolet 235 , it's not a big deal like the mighty GMC 302 that's worth $1,000. when it's in VGC .
I'd not expect to make any $ by selling this engine so don't invest more than regular tune up stuff until you decide which way you're going to go .