I recently purchased a 68 convertible with 400 badging, how do I tell if it was originally a 400 car. Also, could you get the 400 engine with the flat hood, or were they all scooped? Thanks

All 400 cars got the twin scoop hoods. 400 car are only positively identified by sending the vin coding into PHS (Pontiac Historical Services)$35. I dont know of any positive way of identifying a 400 car besides this.

Check your cowl plate..If a 400 car, 3rd group should be 3F.

Works for both my 67 400 cars..68?

As stated prior, PHS is the way to go..

I dont beleive 68 400 could be ID using the cowl tag codes like the 67. Not positive.

Pontiac historical services is definately the way to go. My packet just showed up yesterday. For $35 they dig up the original billing history from microfilm for your car and burn a copy. Then they help decode the codes. It even has a 6 digit "engine unit number" that may be the serial number on the block, though my original engine is long gone. If that is the engine serial number, that could be the way to prove "numbers matching", since VIN # weren't on engines back then. You also get a prety good size stack of goodies. For good measure they stuck in a sales brocure for the new GTO's.

Correct..68 cowl plates did not have that info..

The vin number on the car is also on the engine block. It is located on the passenger side front of the block next to the bottom of the timing cover.