I located and acquired an E0BE-6090-BB head, probably from an 83 Granada, to replace my C6 original head. I'm in the process of prepping and painting, decided to compare the intake valves with my original just for verification. Found them to be the same, 1.649 instead of 1.75 as indicated as spec for the head. Is it safe to say that someone replaced the intake seats and valves with what was used in the earlier versions? Should a machine shop be able to acquire the appropriate 1.75 seats and valves?
All Small Six Cylinder Head Swap on 66 200 - Questioning Intake Valve size
- Thread starter ncpe2001
- Start date
This relates to all small sixes
People do some strange things but why they would put in smaller intake valves makes little sense. Yes a machine shop could do that to change them back to a 1.750 or you could even go bigger up to max of a 1.88 intake and 1.5 exhaust valve depending on your engine build plans. Good luck.
If you are getting new valves, SI makes the proflow which has the narrowed stem under the valve head.
After you lap the intake valves in perform a 30 degree cut to right at the inner lap edge. Average gain is at least 5-10 HP depending on the rest of your build.
After you lap the intake valves in perform a 30 degree cut to right at the inner lap edge. Average gain is at least 5-10 HP depending on the rest of your build.
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