What is Considered 'Numbers Matching' & Effect on Value?
 

Just pulled the motor & trans from an all original 1970 L46 coupe that I bought in May. It ran well, but had sat for a long time, so lots of leaks, needs a clean up, clutch, etc. and I am rebuilding the motor at 80K miles.

It is an original, numbers matching car. I was considering oiling down and storing the original motor, but don't want to go through that, so have decided to rebuild this 350, punch out to 355, lower the compression for pump premium, upgrade the original distributor. I am planning on aluminum heads and intake, retro roller, headers. I will have the machine shop retain the original stamp on the block. I am keeping the original Muncie in the car, upgrading clutch, detail the engine bay, have the radiator checked out, etc. This will not be a street/strip car.

Questions: If I retain the original block, but pull the original heads, is this still a "numbers matching" car? In short, what keeps it as such without completely wrecking it for someone in the future if they are more a "purist"? How will the planned changes affect the value in reality?

I am not the purist/concours guy, but am not a savage. I respect those with pristine original restorations, and realize that what I have here is a complete original that needs some work. At the same time, a 400hp 10:1 roller motor with aluminum heads & intake + headers is what I need to be happy. I already oiled down and wrapped the original heads and will retain the original manifolds, but haven't bought the new parts yet. Where should one draw the line? We plan to keep the car in the family for a long time, but the day could come when I won't be around and maybe it's not my son's cup of tea, so what I do now can help retain the best scenario if it eventually goes to market? I know it's not a $50K car, but it's pretty nice. Thoughts?

Thanks,
Joel

Hi Joel,
A 70 350/350 coupe is a pretty desirable car so you might want to be careful just what you do to it, while still making it be what you want it to be at this point.
The phrase 'matching numbers' means many different things to many people.
Probably in it's simplest form it refers to the VIN stamped on the engine's pad and transmission case matching the car's VIN tag on the windshield post.
I'd save ANYTHING you take off the car and it's engine that you even just think may be original to the car if you have the space.
Regards,
Alan

Will do. Now rethinking a bit. I like the fact that the original exhaust can be tucked up tight w/no flanges hanging under the low car. Heads - to upgrade sufficiently for unleaded it just seems to me it would be as economical to bolt on a modern pair that will make more power. Regardless, I'll keep every original part.

to keep the number matching tag, I would suggest keeping the original block and heads.
I like the stock look, but new HP. on the inside stroked, completely Rebuild heads, complete balanced rotating assemble, forged pistons, cam.
this way it looks stock and has original parts, and plenty of HP.

https://cimg9.ibsrv.net/gimg/www.cor...5a3f72a0d1.jpg

Thanks - I spoke with the machine shop today. I'm going to pull the original heads apart, assess what they need and then make the call on heads. I'll hang onto them regardless. My wife says build it as we want to drive it,so may change up some things but will store original parts.

If you can get a copy of the NCRS judging manual for your car you would be astonished at the number of things that have distinct numbers on them, belts, hoses, carb, brakes... Your frame also has the VIN on it. Most people understand the engine number pad so if you keep that and DON'T ALTER THE NUMBERS when you have it machined almost no one will ever know the difference. Be honest and tell the other 15 people what you did and everything will be ok. If you are really worried about value keep the original parts and put them back on when you sell it. Original cars in excellent condition are usually worth more. Poorly modified cars are rarely worth much.

IMO value is the last thing to worry about. It's a car. I built an NCRS Top Flight car and was too worried about it to enjoy it when I was on the road. My 82 is way more fun than the 78 was. Do what you want to it, keep the work high quality, use good parts, keep Bubba away and enjoy driving it.

Bill :flag:

My advice is to do as much research as you can on your car before you touch it. How much of the car is still original, how many were made with your options and how "rare" is your car.
I bought my '73, big block, TH400, fully loaded, numbers matching car about six months ago. After I've been crawling around the car and digging into some mild repairs such as oil leaks, tune up items, checking the brakes, and suspension components, I found that many things have been changed out over the years. Things like the original owner swapping out calipers, shocks, distributor, carb, PS pump, internal engine parts and other components. The original and prior owner seemed to be the types that would exchange OEM parts for cheap rebuilt parts from auto parts stores to save money without any concern of maintaining the originality. So I've found that my numbers matching coupe has the basic original drive train and major suspension parts still on the car, but little else. I plan to retain the original block, but plan to stroke it to 496, add performance components, upgrade the brakes, suspension, and maybe throw in an O.D. trans. I'll store all the "original parts" I remove. Over the years I've found that a beautifully modified car can be as valuable as any original numbers matching one (some will argue that point). When I complete the frame off rebuild of my C3 it will be everything I want as far as performance and handling. It will be beautiful and will retain the classic grace of a C3 Corvette. If the day comes that I sell it, I'm sure it will bring the big bucks, but that isn't really important. Long post but my .04 cents.

Cars are meant to be driven. Not stored in a bubble for the next owner to enjoy. :thumbs:

At this point, it seems unlikely that your car will ever appreciate significantly. That ship has sailed. Just enjoy it and make it into what you want. Keep whatever original parts you replace.

As the owner of a 1970 L46 coupe myself, I would consider throwing the original block in a corner and building another block. This wouldn't be my first choice either, but the nature of the Corvette hobby has made that block (and heads) very valuable when paired with the original car. Crack that block after a rebuild and your whole car is probably worth 20% less.

A lot of corvettes have been saved way before any other car. Probably too many to make the vast majority collectable s in the future .

Make it your own.

If we were talking about one of the six original Carroll Shelby 1965 Coupes, I'd say don't touch a thing. The number six car sold a couple years ago for around $3.5 million. A 1970 production Corvette, not so much.