Chris, a dragster story for you and other digger owners.
My pal's injected, gas SBC 355" front-engined, direct drive rail, which he bought running could only manage disappointing low tens and IIRC about 145 MPH. Randy and I talked a few times about it but the jetting, plugs, clutch slip was all a-o.k.
So, one day at Great Lakes Dragway, Union Grove, WI I talked his bro Ritchie into having him and I tune the Vertex magneto by ear (no kidding) on the in-ground rollers then in use. After it fired, I turned it up a lot until the exhausts were really crackling at idle.....and fought Ritchie to not turn it down! Locked the mag down and pushed it off the rollers.
Randy lined her up and let fly. Previous best e.t. IIRC was 10.10 or 10.09. This run?
9.27 at 158 mph!
Turns out the previous owner bought a used supercharged F/C mag set up to advance the mech. timing up to about 6,500 rpm and then retard down a steep slope very quickly after 6,500 rpms.....while the rail was geared for near 8,000 rpm! Once he had the Ono Brothers, a Vertex dealer in Chicago, re-do the mag he was flying to I heard later 9.01's.
Pays to check every single thing.