Are you sure about your CE number? It does not look that to me or at least the partial shown. Thinking it ends 3355. However the CE decode I use is from a 69 service bulletin and the N does not fit.
Plus based on your SPID the truck started as a C30 base V-8 truck which would be a 2bbl 307.
Did you find the casting date on the block?
Dig up this tidbit too.
"The 3959512 and that whole series of 39595xx blocks were replacement castings for the out of production 283 and 327 blocks beginning in late 68 early 69 when the CE program started. Any replacement engines/blocks before 68 would have used current production engines/blocks. After 69, those small journal blocks were no longer used in production. GM recast the blocks with new casting numbers to service the small journal requirements as follows.
3959532 283 PASS/TRUCK CE
3959534 283 Chevy II/Nova CE
3959512 327 PASS/TRUCK 327 CE
3959538 327 Chevy II/Nova CE"
http://forums.corvetteforum.com/c1-a...olt-block.html