Since I covered small block pushrod guideplates, I figured I ought to cover big block guideplates, too.
First of all, ALL big blocks use guideplates which are retained by the threaded base rocker arm studs used by all big blocks. In addition, no big block from the first one built to the very last one built ever used guided rocker arms so all big block pushrod guideplates are hardened. The only difference between pushrod guideplates used on 1965-74 big blocks was the width of the slot. This was sized to accommodate the size pushrod used.
ALL 1965-72 big blocks used 3/8" pushrods EXCEPT early 1967 L-36/L-68 and 1967-69 L-88/ZL-1. Engines using 3/8" pushrods used pushrod guideplate GM #3860038. It was 9/64" thick with 25/64" wide slots and a 29/64" stud hole. An example is pictured below:
Early 1967 L-36/L-68 used 5/16" pushrods. This included 1967 engines manufactured in August, 1966 and, possibly, later. All 1973-74 LS-4 also used these pushrods. These engines used pushrod guideplate GM #3904378. This guideplate is 3/32" thick, 21/64" slots, and a 29/64" stud hole. A 3904378 is pictured below:
1967-69 L-88/ZL-1 used 7/16" pushrods. Pushrod guideplate GM #3879620 was used. This guideplate is 9/64" thick, a 29/64 stud hole and with 29/64" wide slots. It is pictured below:
Here are all 3 of the Corvette big block guideplates pictured together:
There were also 2 other guideplates used on big blocks, although never on Corvettes. The first was GM #14097005. This guideplate was used on Gen V big blocks used only for truck applications. This was designed for 3/8" pushrods. The second was GM #12562369 used for the 8.1 liter big block used for trucks and the last PRODUCTION big block manufactured by GM. It was also designed for 3/8" pushrods. Both of these are pretty much the same as the GM #3860038 except that they are 3/32" thick and the 12562369 has a 10.3 mm stud hole designed to accept 10 mm studs. I really think that either could be used in place of the 3860038 if one wished to do so.
This photo shows the 14097005 and 12562369 with a 3860038 so you can see how similar they are:
First of all, ALL big blocks use guideplates which are retained by the threaded base rocker arm studs used by all big blocks. In addition, no big block from the first one built to the very last one built ever used guided rocker arms so all big block pushrod guideplates are hardened. The only difference between pushrod guideplates used on 1965-74 big blocks was the width of the slot. This was sized to accommodate the size pushrod used.
ALL 1965-72 big blocks used 3/8" pushrods EXCEPT early 1967 L-36/L-68 and 1967-69 L-88/ZL-1. Engines using 3/8" pushrods used pushrod guideplate GM #3860038. It was 9/64" thick with 25/64" wide slots and a 29/64" stud hole. An example is pictured below:
Early 1967 L-36/L-68 used 5/16" pushrods. This included 1967 engines manufactured in August, 1966 and, possibly, later. All 1973-74 LS-4 also used these pushrods. These engines used pushrod guideplate GM #3904378. This guideplate is 3/32" thick, 21/64" slots, and a 29/64" stud hole. A 3904378 is pictured below:
1967-69 L-88/ZL-1 used 7/16" pushrods. Pushrod guideplate GM #3879620 was used. This guideplate is 9/64" thick, a 29/64 stud hole and with 29/64" wide slots. It is pictured below:
Here are all 3 of the Corvette big block guideplates pictured together:
There were also 2 other guideplates used on big blocks, although never on Corvettes. The first was GM #14097005. This guideplate was used on Gen V big blocks used only for truck applications. This was designed for 3/8" pushrods. The second was GM #12562369 used for the 8.1 liter big block used for trucks and the last PRODUCTION big block manufactured by GM. It was also designed for 3/8" pushrods. Both of these are pretty much the same as the GM #3860038 except that they are 3/32" thick and the 12562369 has a 10.3 mm stud hole designed to accept 10 mm studs. I really think that either could be used in place of the 3860038 if one wished to do so.
This photo shows the 14097005 and 12562369 with a 3860038 so you can see how similar they are:
Comment