1971 Z28 - Numbers Matching Advice


Veteran Member
Dec 29, 2012
Upstate South Carolina
Find another head that is close the date of the correctly dated head... no big deal. I prefer to put aftermarket rods, ARP rod bolts main studs along with custom SOLID ROLLER CAMS or hydraulic roller cams in everything I build just to ensure longevity.
If you run a flat tappet you really should run specific flat tappet HIGH ZINC - AMSOIL or the like to ensure you give it a chance to survive... along with AMSOIL OR LIKE BREAK IN OILS, which have something like 1000 times more zinc than other breakin oils.


Veteran Member
Aug 5, 1999
Oklahoma City, OK USA
The time to define "numbers matching" is before you buy the car, not after. In general parlance, numbers matching refers to the block, numbers matching drivetrain means block, trans and diff and from there you better specify in detail.

Personally I don't care what's inside - those could all be "born with" in a replacement block and that doesn't quite cut it.

Sorry for your bad luck, but it'll only get better from here.


Veteran Member
May 4, 2001
Numbers #s matching to me means the born with Engine, Transmission and Rear end are with the car (Stamped with the VIN). Totally different than a "all original" car. I can guarantee MOST of your restored cars out there do not have the original internal engine components, the valves in the head, seals, seat coverings, carpet... etc..etc..The engine, trans, diff are surely rebuilt on any quality restoration. That engine is probably .030 overbore too. A car that's rebuilt and ALL correct with all period GM parts is a tough feat and a very expensive one. Not worth to most. I'm surprised he even gave you money for the cam replacement. You own a car when you drive off with it as bad as that sounds. I don't think anyone deceived you...Even if you inspected the car personally, you probably wouldn't have even asked and he may not have even known. People look at date code on the big parts.


Final Six
May 21, 2014
Hutto, TX
It's my understanding that as far as rear ends, there is no VIN. On my 73Z, there's a date code on the lower RH side next to the differential cover and an axle code on top of the RH axle tube maybe 4" from the differential.
I can't recall if there's any other numbers like a part number on the differential and axle tubes.

Latest posts