casting numbers

[Robin7TFour]

Greetings , the motor in my 74 has a casting number that says it is for a 68 Z/28 . is it possible to have a 2 bolt main Z/28 motor?
also if that is true, then how do i find out if this is a valuble block?


thank you

robin

 

[Tom73]

I guess that would be possable since, to my understanding, 4-bolt blocks did not come along until '69.

What are the numbers you are going by?

tom...

 

[matchframe]

Weren't the 68 and 69 Z-28s 302 CID? 4 inch bore and 3 inch stroke?

If that is what you have, you have a sweet motor!

Bill

 

[JohnZ]

What's the casting number and date, and what's stamped on the front pad? If the casting number is 3914678, that block was also used for '68-'74 truck, passenger, Chevelle, Nova, Camaro, Monte Carlo, and for '68 Corvette 300 & 350hp engines; it wasn't unique to the Z/28 - the only thing that made the Z/28 engine built off that block unique was a different crank, not the block.

 

[mike weyman]

my 75 has a 383010 block 2 bolt main.this # appears at the very back top of the block on the driver side right by the bell housing of the transmission.the 010 indicates a high nickle block (one of the best if its not)not all 010 blocks are 4 bolt, in fact a 4 bolt is the exception . 2 or 4 bolt has no bearing on performance, in fact it only really counts in true high performance applications.If i'm not mistaken there was only 2 options in 74, small block 350 or a big block.If its a 302 check on the passenger side front right next to the end of the valve cover this # is your serial #this should match your serial#for your car.if not it has been swapped, but thats ok cause its a sweet motor(unless matching #s matter to you. mike

 

[Robin7TFour]

well John Z i appreciate the info. at least its possible i have a corvette block. just had fancy dreams of having something special.

thank you for everything


robin

 

[JohnZ]

Actually, there's no such thing as a "Corvette block" - all the blocks used in Corvettes were also shared with other car and truck lines. Only the internals and external bolt-on parts made the finished product a "Corvette engine", which gave it a unique suffix code on the stamp pad.