DynoDon
Moderator
2024 changes/corrections/additions
Pg 49. Cylinder Head Requirements:
Must be OEM casting only. (ADD) Casting identification and number may not be ground off. Helicoil of the same threads may be used to repair damaged threads on exhaust only.
Pg 49 line #6
(ADD). Bronze valve guides not permitted.
Pg 50: Carb Requirements: line #22. ( Remove) Center inlet hole is NON-TECH (size, configuration, finish), but no rifling, grooving, dimpling, etc. allowed.
(ADD). Center inlet hole may be enlarged. No rifling, grooving, dimpling or any attempt to redirect flow. ( ie, enlargement only )
Pg 51. Valve train. Line #21
Machining to achieve minimum height permitted.
(ADD). No machining allowed to top of lash cap.
Pg. 54. Replace entire information with the following: Previous information was confusing because it was jammed together and missing information.
Header and Muffler Requirements: Any single stage, one-piece header made from .750” OD steel tubing, with the RLV Mini B-91 Silencer (4117) installed at the end of pipe. The B-91 Silencer must be tread fitted to the pipe end. The entire exhaust pipe including the muffler is 15” max length and 10” min length. A safety plate constructed of a piece of 1/4 inch aluminum or 3/16 steel must be attached to the chain guard for the purpose of covering the entire weenie pipe. Total length will be dependent on the type of exhaust system used and must end flush or more than to the very end of the muffler. All sharp edges must be removed. Added protection plate must be bolted to the chain quard with two nuts and bolts either safety wired or double nutted. Exhaust Pipe must be double nutted or safety wired and silencer must be supported by clamped on brace to secure it. Sealer may be used to assist gasket seal. Header may also be run without gasket, sealer only. “Wennie” pipe silencer end cannot be higher than 14 1⁄2” from the bottom edge of the block mounting surface. Tech the pipe by placing engine on flat surface and measuring from the flat surface to the bottom edge of silencer, cannot exceed 14 1⁄2”. Flange for header maximum thickness of .500” / 1⁄2”. Allen bolts of original diameter permitted. Header must be securely wrapped/sleeved from mounting flange to silencer. No wrapping or sleeving on the silencer.
PRO BOX STOCK EXHAUST: (4104) Must be of traditional “candy cane” design, silencer must be directed down and towards the rear bumper. Maximum height from top of header flange to top of pipe curve is 10”. Bottom edge of silencer end cannot be higher than 9” from the bottom edge of the block mounting surface. Tech the pipe by placing engine on flat surface and measuring from the flat surface to the bottom edge of silencer, cannot exceed 9”. All headers must be securely wrapped/sleeved from mounting flange to silencer ... no wrapping/sleeving permitted on silencer. Water/hose clamps may not be used to secure silencer to pipe. Box Stock header length 16 1⁄2” min and 20 1⁄2” max (measured on inside of pipe with 1⁄4” steel tape). Sealer may be used to assist gasket seal. Header may also be run without gasket, sealer only
Pg 49. Cylinder Head Requirements:
Must be OEM casting only. (ADD) Casting identification and number may not be ground off. Helicoil of the same threads may be used to repair damaged threads on exhaust only.
Pg 49 line #6
(ADD). Bronze valve guides not permitted.
Pg 50: Carb Requirements: line #22. ( Remove) Center inlet hole is NON-TECH (size, configuration, finish), but no rifling, grooving, dimpling, etc. allowed.
(ADD). Center inlet hole may be enlarged. No rifling, grooving, dimpling or any attempt to redirect flow. ( ie, enlargement only )
Pg 51. Valve train. Line #21
Machining to achieve minimum height permitted.
(ADD). No machining allowed to top of lash cap.
Pg. 54. Replace entire information with the following: Previous information was confusing because it was jammed together and missing information.
Header and Muffler Requirements: Any single stage, one-piece header made from .750” OD steel tubing, with the RLV Mini B-91 Silencer (4117) installed at the end of pipe. The B-91 Silencer must be tread fitted to the pipe end. The entire exhaust pipe including the muffler is 15” max length and 10” min length. A safety plate constructed of a piece of 1/4 inch aluminum or 3/16 steel must be attached to the chain guard for the purpose of covering the entire weenie pipe. Total length will be dependent on the type of exhaust system used and must end flush or more than to the very end of the muffler. All sharp edges must be removed. Added protection plate must be bolted to the chain quard with two nuts and bolts either safety wired or double nutted. Exhaust Pipe must be double nutted or safety wired and silencer must be supported by clamped on brace to secure it. Sealer may be used to assist gasket seal. Header may also be run without gasket, sealer only. “Wennie” pipe silencer end cannot be higher than 14 1⁄2” from the bottom edge of the block mounting surface. Tech the pipe by placing engine on flat surface and measuring from the flat surface to the bottom edge of silencer, cannot exceed 14 1⁄2”. Flange for header maximum thickness of .500” / 1⁄2”. Allen bolts of original diameter permitted. Header must be securely wrapped/sleeved from mounting flange to silencer. No wrapping or sleeving on the silencer.
PRO BOX STOCK EXHAUST: (4104) Must be of traditional “candy cane” design, silencer must be directed down and towards the rear bumper. Maximum height from top of header flange to top of pipe curve is 10”. Bottom edge of silencer end cannot be higher than 9” from the bottom edge of the block mounting surface. Tech the pipe by placing engine on flat surface and measuring from the flat surface to the bottom edge of silencer, cannot exceed 9”. All headers must be securely wrapped/sleeved from mounting flange to silencer ... no wrapping/sleeving permitted on silencer. Water/hose clamps may not be used to secure silencer to pipe. Box Stock header length 16 1⁄2” min and 20 1⁄2” max (measured on inside of pipe with 1⁄4” steel tape). Sealer may be used to assist gasket seal. Header may also be run without gasket, sealer only