Deltas between a 350 HP ( L-79) and a 300 HP (L-74 ??) 327
 

Since the blocks had the same casting numbers, I assume the blocks are identical. Is that true? They also had 2 bolt mains ? Did the 365 and 375 HP fuelie also use the same block? Where did the extra 50 HP come from? cam, heads, intake manifold?
If I have a 300HP block what do I have to come up woith to make it an L-79?

Re: Deltas between a 350 HP ( L-79) and a 300 HP (L-74 ??) 327 (clearrun)
 

You pretty much hit the whole list of differences. Bigger valves, bigger exhaust (IIRC) being 2.5" versus 2", alluminum intake, hotter cam. That about sums it up. :smash:

Re: Deltas between a 350 HP (Denney)
 

About 90 percent of the difference between the L-75 (300HP) and the L-79 is accounted for by the cam, so the 151 cam is the best bang for the buck, and you can leave everything else as is, but pocket port and port match the heads/manifold. This will gain 5 to 10 percent in top end power, without affecting the bottom end. Run the 1.94"/1.50" valves, but increasing the exhaust to 1.6" has some benefits. Increasing the inlets to 2.02" just increases the chance of getting a crack between the seats. If you want to spend money, get the engine blueprinted and install a set of Crower Sportmans rods. Select a piston/gasket combination that will yield 10 to 10.5 CR and MEASURE EVERYTHING so you actually know the true CR. All the other OEM or equivalent parts are just fine and spending money to "upgrade" then is just cosmetic in value.

If your 300 HP originally had a manual trans it already has the 2.5" manifolds and pipes. The cast iron manifold and AFB or Holley will work just fine with the 151 cam.

Duke