HI has 3 x uses:
1965 250hp 327 4BBL manual with A/C Corvette.
1968 250hp 327 4BBL manual full size.
1969 250hp 350 2BBL full size.
You'll only find the HI though on the end of the date code on the engine number pad, not in the casting.
1965 250hp is a different engine, it is the base 327 for Corvette in 1965. It won't normally have a code as it is the base V8. It won't be a Quadrajet either, but a Carter or one of those earlier Rochester things.
The HP ratings are SAE Gross so exhaust doesn't come into the equation, but exhaust manifolds do.
The 1968 250hp 327 L48 HI is the same engine we got here in the GTS327. I agree that some US literature shows this engine option as 75cc heads and between 8.5 and 8.75:1 compression, and this is what is in the technical data also. BUT this is the problem, as our 327 and any others from Tonawanda (which will include Canadian stuff as they didn't make 4BBL 327's so would have imported them from Tonawanda) got 69cc heads for about 9.1:1 compression.
The 1967 4BBL 327 was 240hp I think as it had 75cc heads, as that is the only difference I can find between the 1967 4BBL 327 and the 1968 version with 69cc heads(that we got here). Same Quadrajet, same inlet manifold, same cam, same dizzy. Finding data on the 4BBL 240hp 1967 engine is hard though as it was a rare option.
Edit - I just found what the 1965 250hp 327 is. It is 10.5:1 engine, and is PO L30 in full size Chevy. This is the 1965 version of the 1967-1968 L30 which was 275hp - the main difference for 1967-1968 is a slightly smaller but hydraulic cam and slightly less compression (slightly larger combustion chambers for 10:1) and the biggie - a Quadrajet (the 1965 got a Carter) which is where most of the extra peak hp comes from as the Crater is a far smaller carby.
Edited by user Sunday, 8 May 2016 8:16:16 PM(UTC)
| Reason: Not specified