hi, i recently disarmed my 260z engine, i cheked the numbers on head and block and they are: E88 & P30, are these numbers from an L24 ?

Those are casting numbers, and both of those were used on both L24 and L26 engines. To verify what you have now, you need to look at the block serial number, not the casting number. It will be on the spark plug side of the motor, on a pair of raised bosses at the top edge of the block, near #5 plug. The rear boss will have the engine type stamped in (L24, L26 or L28), the front boss will have the sequential serial number.

next to the block number is "3205E"

Wrong side of the block. Look near the #5 spark plug.