Several months back the motor in my 72 kicked the bucket. The motor wasn't original (random late 70s big chamber head). So I pulled it out & in the process of rebuilding it I came across what was thought to be a 1970 350/350 corvette motor. A family friend had it. So on an impulse buy I sold my motor after the rebuild & bought it for a deal of $1k. He claimed to have ran the numbers on it & rebuilt it with a custom cam cut to factory spec. He is an older man & didn't have any use for it & he knew I had a C3 so I believe that's why he gave me a deal on it. I have found it to be a 1971 LT1 motor.

Specs From The Motor:
Block 3970010
Heads 3973487
Intake 3959594
Left Exhaust Manifold 3872765
Right Exhaust Manifold 3932461

From what I have found this comes back to a factory 1971 LT1. So my question is, should I run this motor or sell it? Or keep it & not run it ? I know the LT1's were of limited production. My car is not an original LT1 equipped car. So I'm not sure if this motor would add any value to my car or not. What is this motor worth? Maybe someone is out there with a 71 LT1 car without their original motor looking for an original motor? I don't know. I plan on tearing it down again to make sure everything looks good & having another cam ground to spec just to make sure it is correct since he thought it was a 350/350 for some reason. Peace of mind ya know. He claimed that the heads are 2.02/1.60 & TRW Pistons. When I pulled the valve covers off to check the casting number I notice they have guide plates on them. Which all sounds right for an LT1. All comments & opinions are welcome. Thanks
-Matt

 

I would check the pad #s,, 010 blocks were used on base motor cars along with LT-1s, L-46s,
and so on, an LT-1 motor by itself thats all done would be a nice motor for your car, $1000
sound like a fair buy

 

I agree. What is the engine ID suffix?

 

Does it have solid or hydraulic lifters?

 

I have a 72 lt1 motor. From the factory its supposed to be the same as yours. Solid lifters guide plates, etc. Runs great but those heads are 76cc chambers. If you want more power just put on some 64cc chamber heads. I have to wait until it warms up, and thats one of the spring time improvements for my vette. I hope to dyno it before and after, but I havent found a local dyno yet

 

Hi 72,
You're right in thinking that if this is an LT-! engine someone might be very interested in it.
On the block there's a flat pad located in front of the right side head on which there are typically two stamps:
The first indicating when the engine was assembled and in what configuration.
The second is a VIN derivative indicating what vehicle this engine was first installed in.
Check those numbers and you'll begin to know what you have.
Regards,
Alan

An engine assembled at the Flint Plant on January 7th, as a 270 hp engine.
Installed in a 71 Corvette #6589.

 

I have tried & tried to read those numbers but they are not very clear. Is there any way I can make them readable? I'll post a picture of it later on when I get back home. All I can make out of it is "2299"

 

Hi 72,
It's impossible to suggest what you might do to make the pad more readable without seeing it.
BUT!!!! Don't use anything ABRASIVE or CAUSTIC to try to make the pad more readable.
At this time the most important thing is to PRESERVE whatever is still there.
So post some pics of what you have BEFORE you do anything else.
Regards,
Alan

 

Ok, l'll wait for advice. Is it possible for those numbers to just wear off after time? They don't seem to be like the numbers that are cast into the heads/intake. I hope it's salvageable. Like I said I'll post some pics several hours from now when I get back home to the shop.

 

Ive used muriatic acid to raise destroyed serial numbers on guns. I guess it depends on how bad they are. You can buy that acid at home depot/lowes. Its for cleaning tile grout and will clean off a few microns of soft steal leaving the hardened serial number. I had to do a couple of rubs with it. Use eye and lung protection nuetralize with a base. Read the instructions.

keep it away from paint, rubber, skin, etc......

 

No. They are stamped into the engine pad. They can be machined off.

 

if they are barely readable, they could be filled with paint, oil, and dirt.
Dont wire wheel the paint, use a paint remover or heaavy degreaser first. If they are destroyed buy grinding, that weak acid could raise them. Post a picture first.

 

once the pad is machined off, called "Decking the block".
which is frequently done during a rebuild.
You loose your number matching block, after that is is just another Small Block Chevy motor.

 

Alright guys this is what I'm working with...doesn't look promising. Let me know what I can do if It's possible to be improved. All I can read is 2299 & possibly a 3 6 further over to the right.

 

I see a 3 and a6 after the initail stamp.

this is how my stamp 72 looks, so Im not sure what yours is from without the build code. You could try raising it with some white paint on a rag to high light any stampings. Then if all else fail try the weak acid as a last resort.

 

Would it be smart to sand off the surface rust, hit it with degreaser, then try the white paint? The paint wouldn't just cover it up?

 

Dont sand it, any scratches will make it harder to read and some people don't want to destroy the broach marks from the original machining.

just put a tiny bit of paint on a rag and rub it into the surface, then wipe it of with a rag damp with acetone on it. the idea is to fill in any depressions on the surface and wipe the surrounding area clean. The block looks pretty worn but this process can bring out any thing that can be barely seen. If you want to clean it use a degreaser then a paint remover with a nylon bristle brush to get all the depressions clean.

another method would be to cover the tab with a very thin piece of paper like tracing paper and do a rub with a soft pencil very lightly like doing a gravestone rub. any depression will not transfer the lead of the pencil, but you have to go very lightly

 

Hi 72,
The 2 stamps on a Corvette sb engine pad were done at 2 separate locations, (Flint and then St.Louis), using 2 different 'gang holders', and at 2 different times.
The 2 stamps were, however, done in typically 2 SPECIFIC areas on the pad.
On your pad the larger stamped digits (the size used for the assembly stamp) are in the location that the smaller derivative digits are typically located.
I'm not saying this couldn't have happened but it's not something I've seen.
Perhaps someone with more experience looking at sb pads will voice their thoughts on the pad and stamps.
Regards,
Alan

 

FWIW: Looks like the engine pad is not going to be any help with solving the mystery of what you've got.

 

Could it have been a CE engine?