6066 (1960-1966) GMC Truck Club - Swapping out a 305 for 351 or 401?

Well i was ready to pull the trigger on that 351 a lot of you helped me rule out was not a magnum.. But when i got back over there to do a compression test i found that the oil cover under the air intake manifold had a lot of dirt on it. As i was cleaning out the space around the plugs, I just barely touched the cover with a scrapper and it caved in, rusted out. But we continued on and tested the number 6 cylinder, it came back at 90 psi after about 8-9 cranks. :banghead: I had to pump the breaks right there! So still on the hunt for a 351 or 401. Heeeewww dodged a bullet there....

I have some questions....

Let me just preface this here that im no SAE mechanic! Im not a complete idiot but in no way have i ever tried to do what im attempting with this motor swap. Luckily i have some guys that i trust that are and have all the resources needed to pull it off. Im trying to get some more info on what i might be in for.

So I got a few questions on going from a 305 to a 351-401

1. What important parts are NOT interchangeable?

2. Are these the exact same blocks with just different bores?

3. Where should i be looking for signs of needing a rebuild or major tear down?

4. If i need all new seals whats my best resource to find them, can i find them?

5. Can i get rings, bearings, pistons all that is needed to do a rebuild? If so where..

6. What don't i know that i should be asking?

7. Ill stop there for now.

Thanks for any n all feedback.

azcbass
66 GMC Open Road Camper
Tucson