TM 10-3930-660-34 3-7. CYLINDER HEAD ASSEMBLY - REPLACE/REPAIR  (Cont’d) a. To install service valve guides 3906206 (thin wall intake and exhaust guides),machine cylinder head parent metal valve guide bores (B) to 0.4375 - 0.4385 inch diameter. b. To install service valve guides3904408 (thick wall intake) and3904409 (thick wall exhaust),machine cylinder head parent metal valve guide bores (B) to0.5507 - 0.5517 inch diameter. 3. INSTALL SERVICE VALVE GUIDES (14). a. Install service valve guides 3906206 (14). Lubricate valve guides with engine lubricating oil and press guides into cylinder head (6) until they are flush with bottom of guide boss at C. If necessary, trim service guides (14) so they are flush with top of guide boss at D. Note the reference dimension E. Finish ream service valve guides (14) to a diameter F of 0.3157 - 0.3165 inch. b. Install service valve guides 3904408 and 3904409 (14). Lubricate service guides with engine lubricating oil and press guides into cylinder head until guide is 0.4803 - 0.4843 inch above cylinder head. Finish ream service valve guides to a diameter of 0.3157 - 0.3165 inch. 3-42