GM part #'s

[Mike #32651]

I would like to know part #'s for lifters, pushrods, & rocker arms for my 1969 L46 (350/350) with the 3896962 camshaft. I think the lifter p/n is 12371044.
Thanks, Mike

[Joe L.]

Re: GM part #'s

Mike------

The original lifters for your application were GM #3799644 which were discontinued years ago. The correct currently available lifters for your engine are GM #5232720. These lifters are also available in a kit of 16 under GM #12371044, which you mentioned. If one is replacing the whole set, the lifter kit is, pricewise, the way to go.

The original pushrods used for your application were GM #3796243, which were discontinued quite a few years ago. These pushrods were actually a 3 piece pushrod but they appeared as one piece. The currently available pushrods for your application are GM #14095256. These pushrods use the "welded ball" ends and are, consequently, a 3 piece design which is easy to discern as such.

Kit GM #12495491 which you mentioned are a special HD pushrod which are SERVICE-only pieces. The kit contains 16 of pushrod GM #14044874. These pushrods feature a heavier wall thickness than the standard, PRODUCTION pushrods described above. What's more, their external configuration is VERY similar to the original 3796243. I would recommend that you use these pushrods.

The original rocker arms used for your application were GM #3843359. VERY late 1969s may have used rocker GM #3974290. Both rockers are virtually identical and are non-guided type rocker arms. Both are high quality, parkerized, stamped steel rockers arms. Both have an "O" stamped on the inner surface near the valve end.

The 3974290 rocker arm, which replaced the 3843359 for SERVICE in 1970, was itself discontinued about 15 years ago and replaced by GM #10089648. The latter rocker arms are all that is available from GM today. These rocker arms are of the guided type and are, therefore, configured differently on the valve end than were their predecessors. Functionally, the guided rockers are an improvement and that's why GM discontinued the previous part in their favor. The guided rockers eliminate the need for rocker guide plates and provide the effective benefit of rocker guide plates to engines not originally so-equipped (your 1969 L-46 was NOT originally equipped with rocker guide plates). However, they are not "correct" if that's important to you (not that anyone will really ever know the difference). The 10089648 rockers are available in a kit of 16 under GM #12495490.

If you wish to use original style rockers you will have to use aftermarket, non-guided type. However, these will lack the "O" on the end. Otherwise, you can seek out NOS or use good used original rockers, if you can find some.

[Mike #32651]

Re: GM part #'s

Thanks Joe, you cleared up a lot of confusion.

[Clem Z.]

Re: GM part #'s

joe you can not use the "guided" rocker arms on engines that have tne "double D" shaped pushrod guide holes in the heads because you will get a binding because you are trying to "line up" 3 points. the 3 points are the pushrod,the rocker stud and the valve stem tip. to use the "guided" rocker arms you must enlarge the "double D" hole in the head with a 7/16" reamer so you only have 2 points to align and the pushrod can float "free"

[Clem Z.]

PS so there is no confusion

the "guided" rockers arms can only be used on engines equipted with hyd lifter camshafts.

[Joe L.]

Re: PS so there is no confusion

Clem and Mike------

Yes, however, these should not be a factor for Mike's 1969 L-46. The push rod guide holes for the 3927186 or 3947041 heads used for 1969 L-46 engines do not exhibit the configuration Clem described. Also, of course, the L-46 engine uses hydraulic lifters so the guided rockers will cause no problem there.

Actually, I think that it might be possible to use the guided rockers with mechanical lifters if one used a narrow width feeler gauge for adjustment and slipped the gauge between the guide "rails". I've never tried it, but I've often thought about the possibility. Certainly, adjustment would be a bit more tedious, but it would seem like it could be done.