Background, the engine is a 4 bolt main 350 bored 60 over. Roller cam that back in the day we would call a 3/4 race cam (🤣) and aluminum FloTech heads. All fresh work from a machine shop that builds engines for a couple of the guys on Street Outlaws. Long time reputable local business. Topped with a 750 cfm Holley Street Demon carburetor. It has approximately 350 miles on the build. It has developed a miss on the passenger bank. Before I start doing a bunch of diagnostic work, I thought I would give you racer guys a shot at it. Attached you will see 2 infrared photos taken while the engine is running. The first is the drivers side and the second is the passenger side. Further the exhaust coming out the drivers side tailpipe is fire red while the exhaust coming from the passenger side is more orange. What do you think? See anything out of the ordinary?
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
It appears you've already done some preliminary diagnostic testing. At first glance both banks appear balanced...no cold spots, etc. If it is a miss as you imply try the tried and true broom stick handle method. At each cylinder across the valve cover in an attempt to pick up any noticeable pitch change
Although the plugs will narrow the field fairly quickly.
I'd go a step further and use a laser temp gun on it and see which cylinder is running cooler during miss fire...I've had good success with that method,also I've used a ignition lead tester(snap-on). Last method is a pair of very well insulated pliers and pull a lead at a time to find miss...I'm not a fan of that way, got a few good jolts over the years no matter how carefull I try to be!
All engine speeds. Couldn’t find my laser temp gun. Forgot where I put it after it’s last use. Old age!
Update: Thanks to a PM from Hotrod Lincoln I went out this morning and did a quick spark test of #2,4,6,8. After pulling plug wires I determined #6 and #8 were dead. Trip to O’Reillys and 2 new plugs later no miss. Will monitor the situation for awhile to see if/when it does it again. #8 was wet with fuel but #6 was a bit of a puzzle. It showed no fouling. Thanks guys.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
Did # 6 plug look exceptionally clean, like too clean? You may want to pull the rest of the plugs so that you can compare what they look like compared #6. If #6 is much cleaner than the rest of the plugs like it has been steam cleaned, you might have a minor coolant leak into #6 combustion chamber. I had this issue with a fresh rebuild on a 350. It had a crack in the head. Carl
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
No Carl, #6 had deposits on it but not even in color all the way around. I’m going to monitor the engine for awhile and if it starts missing again I will test further. Thanks
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
