What is the correct 1968 Road Runner 383 Air Cleaner Pie Tin ??

[Car Nut]

Thats a possibility. The other thing I heard was a slightly different grind on the cam, windage tray, and one other thing I can't recall now that were on HP engines vs. the non-HP engines.

I heard the valves in the heads were bigger.

 

[69Coronetrt]

The claim in the ads said the 383 Magnum had the HP 440 intake , heads , cam and IIRC exhaust manifolds...........................................MO

The 4bbl intake and exhaust manifolds were the same between the 330 and 335. (A 440 intake will not fit on a 383 due to width)
The cam and valve springs in the 335 were the same as the 440 HP.
The cam and springs in the 330 were the same as the 440 350 horse version.
The valves are the same.
335 horse got the Carter carb
330 horse got the Holley carb.
335 horse got a windage tray.

I've heard several reasons as to why the 330 horse was used with A/C.