JOEM,

What I am saying is that the previous owner switched engines for some reason, most likely because the original engine was damaged or worn out. The engine that replaced it is not a more powerful engine, at least not noticeably. Let me explain:

All pre 1972 GM engines were rated at Gross horsepower, which means they measured the horsepower at the flywheel of engine with no accessories on it to rob power ( PS pump, alternator, AC compressor, Fan etc.)

Starting in 1972, GM began rating all of its engines a Net horsepower, which means they measured horsepower at the flywheel, with all of the accessories installed including breather and exhaust manifolds. The difference between Gross and Net ratings for the same identical engine can be as much as 25% depending on the accessories. So, an engine with a 250 HP Gross rating in 1970 could yield as little as 188 HP Net rating by post 1972 standards.

So you can see that the 1970 250 hp motor in your car, if compared to the rating system of the original 1978 185 hp motor, is probably very comparable in power output, maybe a little more, but not enough to justify changing the motors out.

If the previous owner just wanted more horsepower, a simple intake and carb changne or headers would have been much simpler and yielded a higher horsepower gain than the engine swap that was performed.

The original '78 engine should have a dual snorkel type breather that has an inlet in the front connected to a flex hose and duct over the radiator and an inlet on the right side connected to a flex hose and duct on the right side of the engine compartment. If it just has one open inlet on the drivers side, it is probably the breather off of the 1970 engine.

As far web sites that trace VINs before 1980, I don't know of any. You might try the NCRS web site, they have a wealth of information about Vettes from 1953 and up.

Let me know, If I can be of more help.

Take care

Jon.

THANKS FOR ALL YOUR HELP. I'M DISAPPOINTED THAT MY NUMBERS DON'T MATCH BUT I STILL REALLY LIKE THE CAR. IT HAS A RED INTERIOR WITH INNER CLOTH SEATS WHICH IS HARD TO FIND. I'LL CONTACT YOU ONCE I FIND OUT THE VIN NUMBER ON THE PAD. I'LL HAVE TO LOOK AT THE HEADER NUMBERS TOO.