how can you identify a real sixpack block. thanks

What year are you asking about ?

This question has been a topic on the board many times before....Apparently you need a vin. stamped block with a V engine code in the stamping. Others will chime in shortly,,

No such thing as a 'sixpack' block.

The 340 version TA block leftovers were used on 4-barrel cars at times.

440-4 or 440-6 - same casting number though.

So for a 440, you have to match the partial VIN to a car with a legitimate 440-6 VIN.

I agree 100% with Alaskan T/A. You'd need to take the sequence number off the block & match that up with the complete VIN number from a V-code car. You might get lucky with someone who does Mopar research and has huge lists of VIN numbers to match up with an original block. Having said all that, the blocks are IDENTICAL to non six pack blocks.

For starters it would have be an E-F or G 440 HP block & have the partial vin# of a V code car stamped in it,but lets say the supposed 440-6 block came out of a 71 Jensen Interceptor SP that wouldn't have a vin# stamped into it then what,if its just a bare block you would never be able to tell the difference, if its a complete bottom end that's never been rebuilt you could determine if its a SP eng.by the specific SP internal components & that's about it,there was about 200 Jensen SPs made so there could be some engines around.