I don't know if you are aware 395558 is the block casting number for a 350, not a 403.

 

395558 is a 350 block, not a 403. Measure the bores. They will be 4.057". The 403 has a 4.351" bore. You don't even need an inside micrometer for that.

 

I was expecting a large casting number at the end, did that get stopped later on?

 

Yeah, I was looking at that also, along with the different font on the casting number. It almost looks like the font used on the 455s with that "GST" casting number.

 

There also would be a big 403 cast in the side of the block and possibly a X, if a 403. Let me guess, a big 8 on the heads by the number 1 and 8 spark plug. Betting it is a 73 to 76 350, a very good motor.

 

If you look very closely, there looks like a large 1 preceeding the casting numbers.

 

There were about 750 330 motors built at the very end of the 1967 model year that used 1968 350 block castings with smaller bores. This is documented in Dealer Technical Bulletin 67-T-19. I don't know if this might be one of those blocks or not. If this really is from the 1967 model year, it won't have a VIN derivative stamp on the block. These late 67 330s could have come with #4 heads or #5 heads. The DTB shows both as options.

 

Is there a big "N" on the crank?

 

Looks like an early 350

cast crank, full length cyl walls not skirted like late 350 windowed blocks or 403

non scalloped lite weight crank