Small Block choices: A feller has too many

Hi All,
For my new square body project, Ive got choices.

I have 3 engines in stock, none of which I know much about in terms of history. They all rotate and appear ok-ish.

Number 1
Block casting: 3970010
Heads: 3973487 - some research shows 75 CC chambers

I just started pulling this one apart. Confirm "010" marking indicating high nickel content block casting. 4 bolt mains. GM OEM forged crank. Pistons marked .040 so 40 over. Heads are 1.94 / 1.5 valves. The cam has the following stamped: COMP CAMS 08197. Hyd flat tappet. I can find no info on the cam.

Number 2
Block Casting: 3914660
Heads: 3947040 - initial research indicates 64cc chambers.

Have not opened it up yet

Number 3
Block Casting 3970010
Heads 3932441 - initial research indicates 76 cc chambers.

My goal for the truck is a daily driver for when I put my camaro into hibernation. Will have a 700R4 and the rear ratio is currently 3.07 or 3:08, which I think will have to be changed to something in the mid 3's. I have long tube headers and will be running it old school, carburetor, no computer.

Any insights, advice etc would be very welcome.

I think my choice would be #3, then maybe bore it out .030 and use pistons that would work well with 64cc Vortec or aluminum heads. With the right pistons you could get it to about 9.5 compression, which would work well with aluminum heads as a daily driver. Very easy 325+ horsepower, and good low end torque with a cam in the range of 214-218 @ .050.

The 010 blocks are good starting points. You can always put on whatever sets of heads suit your purpose. I won't suggest any cam (other than maybe a roller) or performance upgrades because everyone has their own preference, but you have some great options.

UPDATE: Option 1 is FUBAR. See pics. Crank has been cut .010 already and is scored again. 3 cylinders are cracked. I magna-fluxed them and, well, you can see the result.

the 391 block shows a 350 for propane

#3, swap the heads from #2 for higher compression and retrofit roller cam. My 0.02$

#3 block and the 64cc heads it is. Block and heads headed to the machine shop Monday. There's .050 piston to deck clearance which is too much. not going all the way to zero deck but probably .o10 to .015. Hardened valve seats and threaded studs and a valve job. I'll port the heads on intake and exhaust side once I settle on my intake manifold and headers. Meanwhile the bodywork and painting is almost done.

Looking good!
If you land @ .015" deck height to piston a .026" gasket is perfect, even better if @ .010"(yes, I'd go this tight too)

I used Mahle .026 head gaskets with my crate 350 and 64cc
Blueprint heads, to try and make up for the low compression of the stock crate engine. I only used a 213/217 @ .050 retrofit roller cam, so it’s set up for low end torque. Runs smooth and has been that way for several years.

I'm not familiar with the other heads without looking them up, but the 487's were some of the more desirable ones back in the day.

It's been a while but I think the 040 heads were the hot ticket at one point in time. Decent flow 64cc,late bracket holes. All from memory. I'll see if I can find some verified info. Well did a little checking the 040 isn't a bad head but it's a 68 327 head so I doubt it's got bolt holes. I had it mixed up with 041s .

Nardulli said:

#3 block and the 64cc heads it is. Block and heads headed to the machine shop Monday. There's .050 piston to deck clearance which is too much. not going all the way to zero deck but probably .o10 to .015. Hardened valve seats and threaded studs and a valve job. I'll port the heads on intake and exhaust side once I settle on my intake manifold and headers. Meanwhile the bodywork and painting is almost done.

Click to expand...

Those heads probably don't have bracket holes. Something to check and think about.