Hard to say sight unseen. Are you certain it's a 429 Super Cobra Jet?
429's and 460's use the EXACT same engine blocks...and frankly, all the other parts too. The only difference between a 429 and 460 on any given year that they were both produced is the crankshaft (stroke) and pistons (pin location).
you are buying a 429 SCJ engine. If it is a true CJ, then it should have these block and head casting numbers:
- Heads: D0OE-R
- Block: D0VE-A
Of course there is more to the equation, but the bare block and heads alone are worth well over
$1000 to the right people.
If the numbers on the block and heads are different than what I posted above, please post your findings here in this thread and I'll tell you what the engine really is.