ChanceALR47

When I was checking to see if my 77 C3 had a matching numbers motor, the research shows that it's a 73 or 74 motor with matching numbers to my VIN. Is that even possible? Would they put a motor that's four-years-old into a new car?
Last numbers on my VIN are 39773. Number stamped on the engine block is V0607CLA
then 17S439773.
What I understand is that motor was for a Camaro with a 400 transmission.
Has anybody ever seen this before. That is them using an old motor or a new car.
You guys are experts and I would appreciate some of your input.
Thank you

Greg

What is the block casting number and date code?
Both on the upper rear, near the bell housing.

Alan 71

Hi C,
Welcome!
It would be highly unlikely if not impossible for your 77 car to have left St.Louis with a 73 engine in it.
The information I'm looking at indicates the CLA engine suffix code was used several times including during the 1977 model year.
For 1977 it identifies a 350 cu.in, 180 hp, 4 barrel engine used with a TH 350 transmission in a Corvette.
Regards,
Alan

V …. Flint Engine Plant
0607…. June 7th.

Easy Mike

ChanceALR47

From everything I read, CLA suffix denotes a block going in a Camaro with a 400 transmission. Block casting number 3970010 is basically the same info. Denotes 302, 327, 350, 4 bolt Main early 1970s block going in a Camaro.
I bought this car from the original owner. Had approximately 60,000 miles on it. He said he's never change the motor. It now has 69000 miles on it. Been in the garage for the last 15 years. Motor was in the Machine Shop approximately 5 years ago. Thought I would get it bored out and freshened up. Not sure if the Machine Shop did they work they said they did.
recently wanted to put aluminum heads on it. That's what started all this. I'm attaching pictures showing the casting number and stamp number and VIN number along with the Dome Pistons. I wanted to know if those Dome Pistons came from the factory.
last 5 digits of block stamp number matches last 5 digits of my VIN number. I think that says it's the original motor, isn't that correct?
both end in 39773.
if you guys could solve this mystery for me I would appreciate it. I really believe the factory put this block in this car. Very strange that block was sitting around for 4 years though.
Block showing casting number and Dome piston Black stamp number with matching number of Vin
VIN number with same last 5 digits as block stamp number
Engine in car with heads off. Showing Dome Pistons

Alan 71

Hi C,
The stamp pad looks pretty nice, very much what I'd expect to see.
The marks in the surface of the block left there when the block was 'broached' at the assembly plant look quite typical.
The Engine Stamp Suffix CLA indicates what the engine WAS when it left the engine plant and went to St.Louis to be installed in a Corvette.
The original pistons were 'flat top'.
Regards,
Alan

Not too crazy about the pop rivets used to attach the vin tag to the a-pillar.
Has this car had some rust 'repairs' done to the windshield frame?
Maybe a different style rivet was used in 77?

bmotojoe

The 5th digit of your vin tag designates (L) L48 motor. L48 had 2 bolt mains. If it were equipped with the L82 that 5th digit would be an X. The L82 would then have 4 bolt mains.

ChanceALR47

as a matter of fact, yes. I have had the window posts and windshield frame replaced. Like most of those Corvettes they were rusted out and leaking. So I had it all done at the body shop years ago. I forgot about that. Also what is it mean when you say the block was broached? You seem really knowledgeable.
if the motor came with flat top pistons, I guess the Machine Shop did do some of the work they said. They must have put those pistons in them selves. I had to pull the radiator and condenser to pull the camshaft out. Looking for a good top end kit to put in. I sent the aluminum heads intake and cam back to Procomp. They sent me 59 cc heads which were wrong and charge me to ship them back. That pissed me off so now I'm looking for another company. Maybe Summitt or JEGS. Problem I have now is, They're asking me what size volume Pistons I have. I don't know what to tell them. I don't know if pulling the oil pan and looking at the Piston skirts will give me any more info on them or not.
So the bottom line, this is the original motor for the car.?

ChanceALR47

that's where part of my confusion comes in. This is a 4 bolt main block. And it's stamped with the same number as Vin. Which denotes it's the original motor.

bmotojoe

I cannot see my vin rivets as they are covered by the vertical cover. (You added to your post when I went to look)

Alan 71

Hi C,
On the right side of the block's rear flange will be the block's casting date.
Look for it.

All blocks were surfaced (broached) as part of the assembly process.
The broaching left a tell-tale surface… faint lines running parallel to the cylinder bores.
The fact that they are still visible indicates it's unlikely the block has been 'decked' at some point in it's life after it left St.Louis.

The stamp pad indicates how this engine began it's life.

The Flint Engine Plant was assembling 5000 engines per day…. there weren't sitting around waiting to go into cars.

Regards,
Alan

L 31 0
The block was cast December 31, 1970.
The engine was assembled on January 7, 1971
The engine went into a car built about the middle of January 1971.

'75

Have you pulled the pan to check for 4 bolt mains? That casting number was used extensively for 2 and 4 bolt main blocks.

TimAT

I don't recall a SBC with domes on the pistons that big.

Greg

"From everything I read, CLA suffix denotes a block going in a Camaro with a 400 transmission."

Chance, your source is simply incorrect. There's no confusion here. The CLA suffix is correct for your car.

68post

Your extremely tall piston domes are to create an extremely high compression ratio. On the order of 11 - 1 to 13.5 - 1 if used with a small chamber cylinder head. Not sure if you are intending to use 110 octane or higher fuel ? E85 ?

Your engine did not come from the factory with "dome" pistons. Those are substantial domes !

HeadsU.P.

You can make some serious H.P. with those slugs. I have 0.120 dome and yours look more than twice the height. Choose your headgasket and cam-lift carefully for valve clearance.
Here is a web site with calculators to help you crunch some numbers. United Engine & Machine.
www.uempistons.com scroll down and click on calculators. Watch your dynamic compression ratio closely. You will need to know how far down the slug is in the bore, head gasket thickness, head chamber size, etc.
And I wish the '77s came with those slugs.

63mako

I believe your block is the one born in your car. As for the pistons they are definitely not stock. It is quite possible the 4 bolt mains were in the car originally as they sometimes ran short and used what was in stock. Or, When it was rebuilt and those pistons were installed they converted to 4 bolt mains. The domes are big but it isn't decked and flat tops yielded 9 to 1 advertised, more like 8.5 actual. With 76 cc heads your likely under 11 to 1. If your doing engine work check piston to valve clearances carefully if your changing cam, heads or gasket thickness.

wendellp601

I thought Corvette engines were painted blue in 1977....

https://www.corvetteforum.com/forums...ue-engine.html

63mako

They were. This engine was obviously rebuilt so was likely repainted at that time. Still like to see the casting date to totally confirm but the stamp pad looks right and correct match with vin.

ChanceALR47

Here's a picture of the date code. Not quite sure how to decipher it.
Heads up, you seem pretty knowledgeable about the Pistons and top-end. I'm basically a backyard mechanic even at 60 years old. Can fix anything but not real technically knowledgeable about the stuff. I'd like to get a good recipe for the top end. I ordered a cam, aluminum heads, and intake from Procomp, but sent them back because they were 59 cc heads and I think they would have been way too high compression. So now I'm back to square one and needing some big-time advice on what kind of a cam and heads to put on this motor. I have an Edelbrock 2101 Aluminum Intake that's been on it. I only original carburetor with the car which was made by Carter has been completely rebuilt and ready to go. I don't know the carburetor size. I'm almost positive it's the original carburetor. Four-barrel. But I'm back to square one with needing to know what Cam and heads to put on this motor. It's not going to be a daily driver but I will be taking it on the street. I'd like to take it to the strip once in awhile or even better yet, put it on the sport track at Palm Beach International Raceway. Just for fun not for serious competition. Oh yeah, one more thing. I'm converting it from automatic to 5 speed. Think I'm going to buy that kit I saw online. Approximately $5000 for the complete kit. Also putting the 2009 ZO6 black wheels on it. 18x8.5 in the front and 18x9.5 in the rear. W 235/50/18 and 285/40/18. If you guys could help me out with some sort of a recipe or advice or maybe tell me what you have I would greatly appreciate it. Right rear of block showing date code. Don't know how to decipher it.