Olds 350's come in a few basic varieties:
1968 - 1972: Smaller combustion chambers, strong blocks, possibility of
Nodular Iron cranks (a close second to the forged cranks that the 330's
used). Four-speed 4-bbl engines had pretty decent camshafts. No EGR. Of
course, if you get a W-31, you've got a pretty great engine right from the
factory. The '68-'69 heads used a smaller exhaust valve than the later
units. The high-compression pistons will make any of these a
high-compression motor. 7/16 head bolts.
1973 - 1976: Larger combustion chambers, small intake and exhaust valves. EGR
intakes, but the #8 heads were not too restrictive (compared to later
units). Block is still relatively strong, with solid main webs. No more
nodular iron crankshafts, but HEI ignitions on the later units are the best
street setup. You need earlier heads to get high compression, even with
high-compression pistons. 7/16 head bolts
1977 - 1980: Large combustion chambers, small ports, EGR, low compression.
They did, however, have ½ head bolts (in common with the 403's and diesel
350's), though the windowed mains on the block make these the weakest
engines to start a performance rebuild from. In reality, however, you're not
likely to blow out the bottom end of this motor on the street below 6000 RPM.
There were also the D- and DX-block diesel 350's that are the heaviest duty
around, and which had ½ head bolts.
Please refer to the Blocks
section as well!
Please refer to the Heads
section as well!
Please refer to the Intake
Manifolds section as well!
Please refer to the Exhaust
Manifolds section as well!
Please refer to the Crankshafts
section as well!
Please refer to the Pistons
and Connecting Rods section as well!
[ Thanks to Bob Barry for this information ]