[Patina Tiger]

Anyone happen to know the horsepower rating and vehicle designation of #46 heads dated December 2nd of 1968? These have the screw in rocker studs.

Thanks for your insight


Alex

[b-man]

The #46 heads you describe should have press-in rocker studs, pushrod guideplates and 1.96/1.66 valves. I had a set once that came on a '69 Bonneville 428 engine.

They came on 1969 290 HP 2-barrel and 340 HP 4-barrel 400 engines and 360 HP 4-barrel 428 engines. All of them came in the big Pontiac B-body cars and were never originally used on the Tempest, LeMans or GTO.

[Patina Tiger]

Thanks for the answer,

Hmm, held over that long for '69? Yeah these heads have the screw in studs. One would use a deep hex socket to remove. The block they are on is a YH code. I will have to see the date stamp for the year.

Alex

[b-man]

Alex,

Pretty much any head cast late in '68 (in the last few months) would be used for a car built for the '69 model year.

Those # 46 heads should have come from the factory with press-in studs and could have been converted later on. Not that it isn't possible to have come from the factory with screw-in studs, but highly unlikely nonetheless.

The '69 YH code block is a 360 HP 428 auto trans engine, the #46 heads used on this engine should have 45-degree intake valve seats. I have one of these YH 428s here in my stash, block is the 2-bolt main variety. The # 46 heads from it ended up on a 350 engine, great head choice for a hot little 350 engine.

Bart