Block codes. Grade my paper?

[cowlby]

72 gmc 1500 Sierra. It has a rebuilt engine from another vehicle. I was told it was a 78 blazer but thats not what I get from the block codes.

I want to ID my engine. The goal is to be able to get engine specific parts by answering year make model with the actual engine info (original auto) and not the truck stats.

Block stamped on flange under head front passenger side
C5Z156659 V0618TYW
Bell housing flange drivers side casting
3970010

My best guess is 350 4 bolt 6/18/1975 in a C10 chevy pickup
I don't know what these mean... L Ls9, conv.cab,

Anyone who cares to check my work or add to it, I appreciate the help.

[special-K]

Yep, by the suffix code (the most specific#) it's a 1975 (truck) 350 4bbl 165hp C10-2500

Conventional cab means a normal pickup/cab & chassis cab. Not a G-series Van or P-series forward control chassis or COE in bigger trucks

[cowlby]

I appreciate your confirmation Special K, and the explanation of the notes.

I wonder out loud (and will look up the answer)...
"What on earth made them look to lower hp to 165? To capture the 4 cylinder market? I think they have 200hp coming from one of those now a days

Best Regards

C

[Steeveedee]

Manufacturers went to the net numbers from gross HP in '71 due to insurance companies going bugnuts over the high HP numbers. I asked that very question of my manager in late '70 when the HP numbers were reduced on the '71 models.