i recently bought a 85 z28. the person said the motor was replace with a 350. so i ran the numbers on the rear of the block and came up with 3 possibilities on mortec.com. 302,327 and 350 any way i can definatly find out what it is? the numbers i found if i read them right are 3970010

Thanks.

 

010 is a very common 4" bore block. Those 3 motor sizes all have that bore diameter, but they have different cranks.

Just based on the probabilities, there are probably 10,000 times as many 350 cranks in the world as 302 ones, and probably 2,000 times as many 350 as 327 ones. Those other cranks are considered far more valuable than 305/350 cranks. So, the odds are very high, like 99.99% or better, that it's a 350.

That's a good thing... you have no idea how many people get told the motor in their car is a 350, but then discover a 305 block casting instead. A very common rip-off.

 

The 010 casting is a good high nickle block. They can be 2 or 4 bolt. As mentioned above it was used for many years with many 4" bore engines and I also think it's going to be a 350.

To determine exactly what the block came from you need the suffix codes. They're stamped onto the pad in front of the passenger side head behind the alternator. If the block has every been decked then the stamped numbers will be gone. They're usually full of dirt, grease or paint.