Question regarding 8.1 front timing cover. I have two motors completely stripped an 2001-2002 and a 2006. The front covers are different. One has a flat cam sensor boss with a smaller diameter sensor hole and the other has a raised sensor boss with a larger diameter sensor hole. Which is the latest? Also on the cam sprockets. One is raised for 180 degrees approx. 3/4" wide for the 'sensor reading' and low for 180 degrees. The other has a low and high area for 180 degrees approx. 1/4" wide each and the same on the other 180 degrees but reversed. Which gear corresponds to which cover. Checked Part #'s on a gm site but wasn't clear with the year changes. Any help would be appreciated.

It is very important to set it up according to the way Mercruiser did originally because the cam sensor has to the read the reluctor on the gear perfectly and has to have the correct tolerances to do so. The PCM is programed to have input readings from the various sensors, When they do not match with the stock flash - you will have problems. My point is you need the timing cover, cam sensor, and the timing gears to match. It would be best to post pics of all to help match it up instead of trying to read into it.

One time we had a 496 come in that would try to run but could not. The 3 seconds it tried to run sounded like a distributor motor that was 180 out - backfiring, spitting sputtering. We scanned the motor it had a cam sensor fault so we changed it and still did the samething. So we pulled the timing cover and some real genius installed a Cloyes hex adjust timing gear set. Anyways ordered all the correct crap and bingo we were done.