Ok, here's the deal. I have a 350 that was in a truck. It came out of a truck that originally had a 305 in it. I know it's a 350 from looking up the casting number on the block. It's: 3970010 which is typically a 70's 350, or possibly a 68 327, but I know it has the 3.48 inch stroke and 4.00 inch bore of a 350. I still don't have the pan off, so I don't know if it's a 2 or 4 bolt main block (this casting could be either) The engine plant is the Ontario plant, according to the STAMPED number. The suffix is CNB, CNP, or CNR. The CNB shows a 1970 302 (NOT) or a 1982 Police motor )Very Doubtful). The CNP & CNR numbers say Belair, Caprice, or whatever.
From the best I can tell, after looking up what the stamped numbers appear to be, I think it is a 1970 "Land Yacht" (Caprice, Impala) motor.
The heads are really beefy on the inside of the valve cover, and there is a raised portion along the inboard valve cover rail. It comes almost above the cover rail. The casting number on the heads is: 3973370
Now, here's the weird thing. I've only seen this on one other block and set of heads. It has a letter "M" with a square around it on the back of the block and in between the center rockers studs on the heads.
Is there something special about this engine? The heads look like they would be great to port because of all that extra material. I'm really curious as to what that "M" in the square is!

Please let me know if you know any more about this engine!

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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

http://www.Mortec.com says the block is a350 or 302, You heads are listed also.


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82 Firebird,355,Cam 224/234, .466/.488,TH350 Tranny,650 HolleyDP,Hooker Headers(I.E. POS) Manual steering
Best 8th et 8.62@80mph.

 

The "010" block is a high nickle content block. Whenever I need to build an engine I'm always looking for one of those. It's a 4" bore and can be 2 or 4 bolt mains. One of the pics of my destroyed 383 shows the "010" casting The production number doesn't mean much for this block unless you're building a numbers matching car. Keep the block especially if it's a 4 bolt.

CNB = 1970 302 4 bolt, 290HP Nova
CNB = 1982 350 4 bolt, 182HP Police B chassis
CNP = 1970 350 2 bolt, 250HP 4 speed police or taxi, Caprice/Bel Air/Kingswd
CNR = 1970 350 4 bolt, 300HP, automatic tranny, Caprice/Bel Air/Kingswd

The "370" heads should be camel bump heads with accessory bolt holes. They were over the counter 64cc replacement heads for the 492's offered in 69-70. They probably have small valves (1.94/1.5) and press in studs unless someone spent the money to upgrade them. These heads were never offered on a production vehicle.

Not sure on the "M" casting. I can only assume it means the foundry where it was cast. I know the big block heads that have a W inside a snowflake were cast in the Winters foundry.

I just went and checked my "370" heads. They also have the "M" casting. Right under the GM and beside the 8. I still think it's a foundry mark.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car and knocking on the SuperPro ET class
383 stroker (carbed) with double hump cast iron heads and pump gas
454 Big Block buildup now in progress for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857
Best corrected ET: 11.163
Best MPH on a time slip: 117.87
Best corrected MPH: 126.10
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car
91 454SS daily driver
95 Homebuilt Harley


[This message has been edited by Stephen 87 IROC (edited November 21, 2000).]

 

That sounds like what I have! I has very little wear in the cylinders, but I still don't know if it beed bored out, or anything though. THe other on ethat I saw was never down, and it also had little wear.

The heads seem to have bigger valves. I don't know for sure what size, but I'm pretty sure they are 2.02 intake...etc.....

It does sound like something I want to hang on to! I already have the block for the Camaro, but I have other projects I can use it for!

Thanks!



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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

i didn't realize that "010" blocks had high nickel content...I got a kickass block and didn't even realize it It's a 4 bolt main as well.

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The '82Z
Hugger Orange
383 4 bolt main
3000 lbs
Bad cornering
NOS Sportsman Fogged
10 bolt braker

Coming to a street near you in the spring...
The car's website

 

In 1991, I picked up a rebuilt long-block .030"-over 350 for the '57: 4-bolt mains, 010 casting (don't know the full casting #, but the "010" was cast in the timing chain area). 6 months later, I have frothy oil. Pull the intake, discover a crack on each side of the valley that goes into the water jacket.

This after having pulled the heads, six weeks after getting the engine running, because of a cracked head (leaked water over the headers). I went back to the shop that sold it to me, see a hand-written sign on the door that says: "You have my money, where's my engine? See you in court." Guy from the neighboring business says he hasn't seen the guy for a while.

I'd suggest a thorough going-over of any used engine. Don't assume that because it's "the good stuff", that's it's good to go.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

there were no '70 302s and if there were they would of been in a camaro z/28 and not a nova.

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-=ICON MOTORSPORTS=-
1st & 3rd

 

That's what I thought, too ede. I thought that Camaro's were the only thing to get a GM 302.

I totally agree with you five, that's why I plan to have it gone over really well. Luckily, the machinist that I deal with specializes in small block chevy's! Maybe I'll ask him about the square "M". I don't plan on putting this engine into the Camaro, (it gets a '98 truck block with fast-burn heads, etc...) but just build it up and have it sitting around for when I get a truck or something to drop it in. Or, I have a couple friends that may want it. Who knows. For the price (free) I couldn't go wrong! I do know that this thing has been really hot before (had a blown head gasket) so I need to check for head warpage. There are no visible cracks, and that's a plus!

------------------
Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

The 010 casting was very common all through the 70s. I have heard all sorts of things about how good or bad they are, but as far as I can tell, there's nothing special about them. They're just a block.

I have had more than one 010 that had the lifter bore problem, where one or more lifter bores weren't oriented correctly at the cam and as a result rolled that cam lobe usually in less than 5000 miles. I also had more than one of those that had the starter bolt hole problem, where the whole bolt pattern was too far from the crank so it was impossible to get it to start right and quit making that awful grinding noise.

Like five7 said, there is no substitute for a careful inspection. Even then there are things you can miss.

Personally I accord no particular significance to the stamped numbers. The casting #s tell the only story that really matters. I find no performance benefit in that cast iron having been wrapped in any particular sheet metal (or fiberglass) during its early life.

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"So many Mustangs, so little time..."