Whats a 427 '69 dated believe its march, has the 5512 block been bored .060, magged, comes with rods, pistons, new rings, timing cover, NEW NOS Gm rockers, 840 mildly ported heads, longblock complete minus crank?

Price would depend on a lot of things.

Does it have anything stamped on the front pad of the block?

Is it ready to run at 0.060 over?

Are the rods and pistons new or in useable condition?

What happened to the crankshaft? If it went bad, makes you wonder if the block needs to be line bored or if anything else might be wrong with it.

I have a similar engine and having been watching pricing for a year or so. If the block is a 4 bolt block and in good shape, pricing on e-bay typically around 2000 - 2500. Being 0.060 over not a great help here.

Porting on the 840 heads actually hurts value. Asking price for a good pair is around $2000 but thats original stuff - not ported.

Pistons and rods not worth much, you might just want to look for a 6223 crank and put it all together. Long block would also include solid lifter cam, lifters and push rods.

Took it to the machine shop to get it checked out, they said a light hone and it could be used, pistons are .060 TRW, dimple rods, and the crank was misplaced by the previous owner, I also wished he had left the heads ALONE!

Finding a good crankshaft won't be that difficult.

what would it be worth assembled?

Really, really tough to say. Depends on how bad somebody wants one. Does it have a partial VIN? It would be worth the most to the owner of the car it belongs in.