We had similar issues earlier this season. Our timing was off along with a worn mag. Got mag fixed and timed correctly and the issue was gone.

check filter at the end of inlet hose may be stop up

New pro mag/coil setup installed last night. I'll report back Monday if this fixes the issues.

Just for my info, could you tell/was there a difference in the brightness of the timing light? There is a huge difference in a couple of ignitions I have, brighter light, more advance, and add more fuel=more Hp. Bob

A msd timing light has a brighter light than one of those flaming river timing lights.

I have neither, I was just trying to get a fix on the brightness of the same light, used on different ignitions, to be able to tell when the ignition might be getting weak, in other words, using the same light, on a new, vs an older ign, did the light brightness change, the difference in mine was huge, the new ignition also had a longer soak, it was with 2 rotors, one a 120*, and one a 180*, compared to a 90*, same coil used on both! Thanks! Bob

new ignition fixed all my issues. Motor ran great all night, 8 lap heat race, took the checker flag @ 210 degrees. 15 lap A feature green to checker @ 210*.

No I couldn't tell any difference in brightness between my "bad" ignition and the borrowed "good" one. I'm using a cheap o'reilly auto parts timing light hooked up to a motorcycle battery out of my 4 wheeler.

Well good, at least someone had some luck this weekend, glad to hear you fixed it, temps are a bit more in line now too, right in the real good range! Thanks for the results! Bob

Yes sir, thanks for the assistance. Now its all up to me to relearn how to drive these cars. Been 8 years since I've raced sprints, won the track championship that year and then switched back to modifieds.

Dry track Saturday night, I over heated the brakes and exploded the inboard cast iron rotor. It lasted 12 of 15 laps. Ooops. I'll have video up sometime tonight. It was quite the spark show lol.