Small block pushrod guides came up in a recent thread so I thought I'd provide some more information in regards to said guides.
Small block pushrod guide plates first appeared for the 1970 model year. They were thereafter used for all LT-1 and L-82 Corvette engines in conjunction with threaded base rocker arm studs. The guideplates used were GM #3973418. These guideplates had slots that were 21/64" wide, a 29/64" stud hole, and 1/8" thick. These guideplates were hardened steel.
After 1980 pushrod guideplates were not used again on Corvette small blocks until 1986 for Corvettes with aluminum heads and also for all 1987 Corvettes. These guideplates were GM #14011051 and their specifications were identical to the above. However, there were 2 slightly different designs for this part number. The first design, which I believe is the design actually used in PRODUCTION, was configured exactly like the 3973418. In fact, I can't really figure out why a new part number was assigned. The second design, which may or may not have been used in PRODUCTION, differed only in that there was a radiused "cutaway" between the guide slots. I presume this was done to improve oil drain back from the rocker area. The GM #14011051 was hardened. Examples of both designs are shown below:
For 1988 all Corvettes were equipped with guided type rocker arms. This rendered guideplates unnecessary and, even, undesirable. However, "guideplates" continued to be used. These were not conventional "guideplates, though, and were actually more of an assembly aid than they were a true guideplate. They had specifications the same as the 2nd design GM #14011051 EXCEPT the slot was 3/8" wide and the plates were non-hardened. These were GM #10111771. These were used from 1988 through 1992. They were dropped from PRODUCTION after 1992 and replaced for 1993-96 by a flanged base rocker stud.
Here are photos of the GM #10111771:
All of the above are GM-discontinued except the 2nd design GM #14011051.
Here is a photo of all of the guideplates together for comparison:
Small block pushrod guide plates first appeared for the 1970 model year. They were thereafter used for all LT-1 and L-82 Corvette engines in conjunction with threaded base rocker arm studs. The guideplates used were GM #3973418. These guideplates had slots that were 21/64" wide, a 29/64" stud hole, and 1/8" thick. These guideplates were hardened steel.
After 1980 pushrod guideplates were not used again on Corvette small blocks until 1986 for Corvettes with aluminum heads and also for all 1987 Corvettes. These guideplates were GM #14011051 and their specifications were identical to the above. However, there were 2 slightly different designs for this part number. The first design, which I believe is the design actually used in PRODUCTION, was configured exactly like the 3973418. In fact, I can't really figure out why a new part number was assigned. The second design, which may or may not have been used in PRODUCTION, differed only in that there was a radiused "cutaway" between the guide slots. I presume this was done to improve oil drain back from the rocker area. The GM #14011051 was hardened. Examples of both designs are shown below:
For 1988 all Corvettes were equipped with guided type rocker arms. This rendered guideplates unnecessary and, even, undesirable. However, "guideplates" continued to be used. These were not conventional "guideplates, though, and were actually more of an assembly aid than they were a true guideplate. They had specifications the same as the 2nd design GM #14011051 EXCEPT the slot was 3/8" wide and the plates were non-hardened. These were GM #10111771. These were used from 1988 through 1992. They were dropped from PRODUCTION after 1992 and replaced for 1993-96 by a flanged base rocker stud.
Here are photos of the GM #10111771:
All of the above are GM-discontinued except the 2nd design GM #14011051.
Here is a photo of all of the guideplates together for comparison:
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