[My427stang]

That could be a 428, could be a 390, is ABSOLUTELY NOT a 429 with those casting numbers

Check for crossbolts above the pan to see if its a 427, but I highly doubt it with the head and intake combo

The S manifold is garden-variety 390GT or 428 PI, as are the heads.

The only way to tell if its a 428 easily, is pull the pan and get the crank casting #, like 1U, 1UA, 2T etc. Once we get the crank # we can see if its 390 or 428.

If its a 428, its worth more, if its a 390, its a great motor but not worth as much