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