What engine would a 1970 GMC 1/2 ton longbox have?

[Russell]

Howdy!

I helped recover a kid's truck after it's starter apparantly failed the other night. It wouldn't crank, but the solenoid was working properly. We wound up flat towing it to his shop, and at that point, I gave him my number incase he needed more help.

He replaced the starter, and found the new one was doing the exact same thing, and eventually found that his engine is apparantly seized up.

He bought a used 305 for the truck, and gave me a shout tonight asking if I could help him replace the engine this weekend.

Of course, I said yes, but I'd be interested in the old engine. (I'm thinkin 70 engine will have higher compression, better flowing heads than I have now)

However, I am wondering what engine would have come in that truck? Would it be a 350, or could be be something else like a 307, or 327?

Possiblity of it having double hump heads?

Thanks!

Russ