L-78 engine Birth date

[JRSully]

I recently had a 70 L78 rebuilt dead stock except for a .030 overbore (70 396'a started life as a 402) 11:1 compression (verifed) nos 143 cam, 569 intake, 4557 holley, stock distributor, stock, uncut heads (hardened seats)stock valve size. Motor was pretty much clearenced and balanced. 422 hp @ 5900 WITH headers, 400 lbs torque on the Dyno. Everything is essentially the same as the 65-69 L78 except the intake (flatter, slightly lower performance) and the I think the 291 heads (70) may have had slightly larger valves vs. the 840 and also what equates to a .060 over bore over an actual 396 inch motor WITH headers, so who knows for sure..