350 Gen I What do y'alls think?

[Andrij]

Hi There! I have a question for y’alls, I’m planning on building a motor for my 1970 C10 to get it up & running. It’ll run (but it smokes grayish smoke if I remember right). I was just seeing what y’alls would advise for the rebuild.
Original block (1970 C10)
Gen 1 SBC 13 GM 391467 Date 237
Now I reckons the GM Code is 3914678 & I just don’t see for whatever reason the last number, but it does match up (along with the glove box ID) & my research has pointed that the block came in 3 varieties:
302 290-290hp 2 Bolt Main
327 210-350hp 2 Bolt Main
--->350 295-295hp.....68....2 Main
Bolt Cast Iron Heads were added later 14014416 1980-1985 305HO, 58cc, 1.84"/1.5" valves, 7 exhaust holes
Will be run by a 600 CFM Holley Carburetor Street Warrior (80457-3 1344) with Electric Choke
My Question to you, any thoughts you have or think I should do with it?
Should I teardown & measure before ordering?
& I see assemblies on Northern Auto (for ex: http://www.northernautoparts.com/part/ek-ek1070 ) & Amazon (same but +$40). What possibilities do you guys see for this project?

*I do apologize for these simple questions, I see videos everywhere on how to teardown, & assemble each individual part, what to shave, what books to read, & what people are doing to theirs but with Gen III & IV it gets kinda confusing if all that is compatible, I was looking for someone that remembers these Gen I blocks & can point out a few doors or directions I can go. Thank you for any advise you may have!

[geezer#99]

If you get the suffix code off the flat pad in front of the passenger side head, it will tell you which motor it is.
And don’t buy anything until you pop the heads off and check how big the ridge is on the top of each cylinder.
You might get lucky and only need to do a quick ballhone and keep your original pistons.
If you find a big ridge you’ll likely be machining it oversize.
Or you might find it is already 60 over and won’t take a bigger bore.
If you can catch your fingernail on the ridge it’ll be rebore time.
And you might need better heads. Those 305 heads add compression but don’t flow well.
Could be a crate motor is needed.

[Dead Parrot]

What's the planned use for the truck? Daily driver? Occasional run to the do it yourself box store? Street monster?

Any idea if the block is original to the truck or was the whole thing a replacement done by a PO? If not original to your truck, depending on which block you have(302, 327) it might be worth enough to someone doing a period but not matching numbers restoration to justify selling it and picking up a crate motor that matches your planned use. Machine work isn't cheap and can quickly exceed the cost of a basic crate motor.

[GASoline71]

I highly doubt it's a DZ302. Not many of those around.

I agree with geezer that the 305 heads provide nothing in the realms of performance. Anything gained by higher compression is negated by the crappy flow and small valves.

Gary

Gary