[SD455DJ]

Originally Posted by HO LEMANS

I can't seem to locate the information I am looking for so again I turn to you guys for help ( which is always greatly appreciated) 2 things what does the factory 390 hp 428 HO air cleaner look like and does anyone have the correct part number?

Thank You
H.O.

Fair warning…there’s a ton of applications to digest here! The ’68-’69 428 HO air cleaners used on B-body & GP’s is a single large snorkel unit also found on 4-bbl high performance engines (except ’68 Ram Air engines in GTO’s & Firebird 400’s). There are several part numbers and codes for each engine (L76 350 HO, L74/L78 400 4-bbl, L79 428 4-bbl; L75 428 HO), however, L75 428 HO’s use PN 6424826/6424827 (with & without K45 HD air filter).

(The ’69 GTO standard engine (WT/YS code 350 hp) was the first use of the dual large snorkel air cleaner PN 6484993/6484994) that didn’t have the California emissions carb bowl vent hole. The Firebird 400 base and HO along with the GP 400’s, still utilized the single large snorkel air cleaners. The ’70 – ’72 dual large snorkel air cleaners with PN 6485778 with the vent hole…plugged for non-CA use.) The ’70 GP/B-body base 400 4-bbl was equipped with the single small/short snorkel air cleaner.

The attached snip from the ’75 Parts Catalog no doubt contains superseded part numbers and appear to have dropped the PN’s for the air cleaner assemblies with the KL45 HD Air Filter for simplicity.

Dennis

[HO LEMANS]

SD that is some great information (alot to digest as you said but interesting for sure) I do have a question that I am confused on if you type the part number 6424827 into google it shows a bunch of dual snorkel air cleaners but the info here shows it to be a chrome lid single snorkel and the duals are 6484993/994 or 6485778 so I have to admit I'm lost I guess for what I'm doing it's not critical to have the "exact" air cleaner but the 6485501 that I currently have will be replacing the missing air cleaner on my 350H.O. so I want to get a replacement 428H.O. air cleaner (honestly I prefer the single snorkel but will be happy with either)
Thank You again for the great info