What technically qualifies the engine as original? Just the numbers matching on the block and heads? Would things like a different cam/intake, boring, stroking, etc. no longer make it original? What things cross the line when trying to get close to an original setup, but squeezing alittle more horsepower than it came from the factory?

Engine internals don't count IMO.

Engine internals don't count IMO.

See, that's my thought as well, because when you rebuild an engine, alot of the parts aren't available. I'm thinking of starting a factory correct resto, and I want to keep the original heads and blocks (and carb) but freshen up things like cam and pistons. Thinking about a possible bore/stroke as well. But I've had some people disagreeing with that idea, saying it messes with the integrity. Just wondered what the experts thought! :D

Beyond the VIN and date stamping on the block, there really isn't any way of telling if the rest of the parts are original or not. Casting dates are a clue as to whether the parts were from the correct time frame but no guarantee that they came with the car from the factory. Very few of these engines haven't been apart over the last 40+ years, even if it was to change leaky gaskets and seals, or to have a valve job done. Judges will be looking for correct stampings and casting dates.

My opiniong for what it's worth: Original engine should be a description used ONLY IF the engine that came in a particular car from the factory is installed in it, INCLUDING block & heads. In my opinion, changing of internal components is an upgrade/downgrade. If it doesn't have THE original block, it's NOT the ORIGINAL ENGINE........... just that simple.

I agree with Norris, the original engine is the first engine put in the car at the factory. With all the restamping going on, I not sure matching numbers means too much today.

I agree with Norris, the original engine is the first engine put in the car at the factory. With all the restamping going on, I not sure matching numbers means too much today.

Do you mean the same exact block/heads or every single part down to the oil pan has to be the same as what went in at the factory? How could you tell which block went to which car?

What qualifies as an original engine?

The original engine, none other can be the original.
It doesn't matter what's inside.

The original engine, none other can be the original.
It doesn't matter what's inside.

I would have to agree with that. The origonal engine is the one that was in the car when it rolled off of the assembly line. As far as the engine is concerned the only component that can be verified "origonal" for sure is the block. As a previous poster posted most other externally bolted on components have a p/n & date code, no possible way to truly verify unless the engine is partially dissasembled. I mean like who has or cares about gaskets, rings, bearings etc. Only a survivor MIGHT could boast about that and that would be RARE( a term that is greatly overused). So I would say do the best you can with what you have and dont try to fake/defraud anything.

Well, I'd like to restore something to start going to car shows with, but I'm torn between a resto and a restomod. What do judges look for in a restoration?

Depends on the judges, most Chevelle show judges don't look at any numbers and wouldn't know if they did look.

I have a question ? what year did GM start stamping the last six numbers of the vin on the block pad, I have an original 63 impala , engine and all and the vin # is not there

How could you tell which block went to which car?

The block usually (on SS's, etc) will have the last 8 digits of the CAR's VIN stamped on the pad in front of the passenger-side cylinder head...

For every car built, there was one and ONLY one original engine with those "matching Numbers"... Thats the reason why true "matching Numbers" is so desired, which in turn leads to the term being abused (and numbers restamped)... A Peeve of mine is when people advertise engines and say something like "make your car matching numbers", etc, as they just assume the casting numbers are all that matter...

Pretty easy (but time consuming) for someone to put together a "correct" engine, consisting of correct casting numbers and even acceptible casting dates for the various components... Its a little harder/more expensive to correctly restamp the block (but getting easier)...


IMO, saying the car has its original engine would imply that it IS the engine the car came with. IMO, I'd allow for normal rebuild/upgrade/replacement pieces if the car was so modified (headers, cam, etc)... BUT, if the car was "restored" with incorect pieces, then I'd think its not original...