I have put 362 miles on my newly-built 505", so I pulled the plugs for an autopsy and replacement. These are NGK BKR5E, been in since initial fire-up and the subsequent driving.
Moving the timing and tune around some, working through the carb it's an older speed demon 850 mechanical-secondary and I've added replaceable air bleeds and PVCR's since they were all fixed on this model. I had it on my last engine too (440) and had it pretty well nailed, this time I'm thinking I might wanna add brass in the IFR's. First drive of the day, even here in the heat it seems to go real rich as soon as I crack the throttle, and stays that way while cruising even at higher speeds (3000 RPM) BUT--after a shutdown/heat soak and another trip, the AFRs creep up and stabilize around high 13s-14 at cruise and in the transition area which is better on the gauge but I'm not thrilled with the plugs and that's all I really care about at this point.
WOT is fatty but I'm not really dealing with that yet. Even up close the thread coloring plays tricks on my eyes but they seem like they could've been a step warm so I have 6's in it now.
It's a 'relatively' mild 250 @ .050 solid FT cam, 112 LSA in at 109. Timing is 22/34 by 2500 rpm and I run the ported advance to start pulling in around 15" which gives me 48 total before the engine maxes out the vacuum. Maybe a little conservative now but it seems happy with that. Idles at 850 with about 8" vacuum and pops up to 12" when I crack the throttle, then cruises between 14"-20". The revs come up real quick while cruising with the 9.5 converter and a 10.5 gave it just a bit of a rich hit in traffic so I'm running an 8.5 PV now with the jets at 82/89 (stock was 85/92). Whatcha guys think? Thanks!
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(some of the gunk on the very tips is from my dirty gloves--lol)
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