67ssimp

I have been given an engine block that I need some help decoding. It has 3970010 casting on the back of it. The vin stamped on the front is T0718CMR. I have searched various times on google for information but so far have not been able to find out anything other than it could be 302,307,327 or 350. I'm working on a project and I'm hoping to find out exactly what it is before I get anymore involved in the teardown.

navy02ws6

Any chance you can get the casting date from the back of the passenger's side of the block just in front of the bellhousing? That would at least tell us the year that it was cast, at which point I could at least narrow it down to a 305 or 350, as the CMR suffix was used only for 350s in '74 and '78, and only 305s for '80. The casting date should start with a letter (A-L), then have at least two numbers after it. The last digit of the casting date will be the last digit of the year it was cast (4=1974, 8=1978, etc.).

http://www.nastyz28.com/gm-chevy-cod...s-suffix-3.php

LeonardS

010 blocks were very popular. Measuring the cylinder bore will get you an answer pretty quickly.

sofakingdom

iTrader: (1)

It's a BLOCK.

It doesn't have CID. It has to be combined with a crank to get that. All it has, is bore diameter.

It's not a 307... that engine had a 3.25" stroke (327) but a 3.875" bore (283). Can't make a 3.875" motor out of a 4.000" bore.

The VAST majority of 010s were 350s. Mostly typical 70s smogger turd ones. Look at the crank; if it's a 442 casting, it's yerbasic cast 3.48" stork unit, and the ENGINE is a 350. I'd guess probably 90% of all 010 blocks came with that crank; and probably 95% of all of the that you'd come across as not particularly special cores, will have that crank now. Sight unseen, my money would be on it being that combo. If the crank is any other #, it'll take more than my memory, in its current state, to tell you what it is.

Odds are probably less than 1% that the number stamped on THE BLOCK is in any way related to THE ENGINE that is now built in it. There are so few all-original 70s smogger turds laying around any more, it's not even worth considering. Forget that stamping. It tells you NOTHING. The BLOCK has long since forgot, and/or ceased to care, what variant of sheet metal it was wrapped in during its first pass through life.

LeonardS

My 69 Z28 has an 010 block, 302 engine. Not part of the VAST majority!

67ssimp

I'll measure the cylinder bore and post again when I find out exactly what it is. I appreciate all the info.

sofakingdom

iTrader: (1)

Yup, it happens. Might even have originally come that way.

Doesn't mean that EVERY 010 block is part of one of those engines.

And for that matter, doesn't make THAT 010 block any different from any other 010 block, on its own; except to people that hunt number stamps. THE BLOCK is the same as the others.

LeonardS

No, it DID come that way. Who said it was different.....you made it sound like they all came in mundane smog cars. Some 010’s came in fun cars.

sofakingdom

iTrader: (1)

Well bully for you!!

No, I didn't say ALL were low-perf smoggers.

What I DID SAY was, the VAST majority were. Which I think is being generous, given how few 69 Z28 302s there were, compared to how many 74 Impalas, 76 trucks, and so forth. Don't forget, engines that included that block casting came in Impala, trucks, Nova, Malibu/Chevelle, … in short, EVERYTHING.

Regardless, just because you have one of that casting # that came in a better motor, doesn't somehow translate to the OP's. The ODDS remain the ODDS.

And regardless of whether or not a few came in better configurations, the ODDS of this ONE IN QUESTION (a) being one of them, and (b) if it ever was, STILL being that and not some mish-mash of who knows what "rebuilder" floor scrapings, are infinitesimally small. The crank casting/forging # will help identify that.

Just being realistic here.

LeonardS

Do you even own a vehicle with an 010 block, or are you the self appointed block expert?

sofakingdom

iTrader: (1)

I've owned several over the last 40 yrs or so. Built even more for others. Don't happen to have any at the moment. I don't fool around with SBCs that are that small anymore. All of them I have left of my own, are 400 blocks.

cs2000

3970010 is for a 350 Block.. on the pad below the right front head you got the other numbers off of, should be a VIN stamping, if its not there, check near the oil filter flange , the VIN stamping may be there also. the 010 casting was used from 1969-1979.

Drew

iTrader: (58)

I had two of them there "high nickle content" 3970010 blocks. One was a 76 350 with 2-bolt mains out of some Chebby, the other was a 78 350 with 4-bolt mains. Both were dished piston clunkers with smogtastical cylinder heads. They're so common I know that casting number better than the castings on any of my thirdgens.

I think what Senoir Sofa is getting at, is that the 3970010 casting in and of itself doesn't really tell you a lot. People like to use buzz words like "Vette" or "High Nickle" or "4-bolt" like it means something. At this point, a second hand engine is a second hand engine. You don't know what it is from the block numbers or stamps, the best you can do is know what it was. That doesn't help much when it's been 40 some odd years since the block was what was stamped or cast upon it.

The POINT to take away from Senior Sofa, is that it's mostly a fool's errand to bother decoding the numbers beyond a trivial pursuit. I mean it's something to do after a day in the shop when you're beat and getting ready to zonk out for the night, but it's a poor substitute for taking it apart and seeing for yourself what it is. You can't trust the numbers, you can't really trust the published lists of casting numbers. Hell, some of the published definitions have had the same typos on several different web pages over the years, and no one has bothered to fix them. You're going to assume an engine hasn't been serviced, rebuilt, "freshened up", "warmed over", or gone through one of the plethora of reconditioning factories?

The rarest exception is the dedicated collector that has sought out a special car and verified what it is. In those cases maybe you can trust it, but for the average guy asking on Thirdgen, he's usually getting a mystery block from some tweeker high on something that's as mysterious as the block being offered. Expect the worst.


Now for my standard issue voice of reason - Is it a complete running engine that already does what you want it to do? Because I don't see how a person can build an old 2pc rear mainseal, non-roller block like that into a decent engine for less than it'd cost to just buy an L31 crate engine from Jegs or Summit. For $2000 you get a new engine from the Vortec heads that are better than anything in the 3970010 era, new rods, new pistons, new crank, provisions for a roller cam, and a 1pc rear main that won't **** oil all over your garage floor or driveway. By the time you rebuild an old set of heads, or buy good heads, recondition rods, cut the crank, line bore the block, bore the cylinders over, hone with a torque plate, etc you'll have over $2000 into a 'free' engine block that wasn't all that great when it was new. Plus a 3970010 won't drop into a thirdgen without headers, if it's a truck engine or otherwise has the HUGE flywheel and you want to make it fit in a 700R4 or T5 bellhousing, you'll need a different flywheel, and/or the starter to match... Yeah, I rebuilt one several years ago, was never happy with it, sold the car, sold the other block because I knew I was never going to mess with that crap again.

LeonardS

Amen!! Mine has been rebuilt, only because it’s in a 69 Z.

NoEmissions84TA

iTrader: (1)

Never mind.