Senenich Propeller

Model 74DM6

Serial A56621

with Art Mattison tip mod and correct STC

250 hours total




If you have a Power Flow Exhaust on a O-320/290 or just want a cruise prop this baby is for you !

This propeller was an add on after installation of a PowerFlow Exhaust system on a PA 28-140 with a 160 hp O-320. The additional hp gain of the more efficient exhaust was allowing the engine to over-rev to over 2800 + rpm in level flight. This was the original prop ( as far as I know ) was pitched to 58" and at sea level with 2 pax and 3/4 tanks was now showing well over 900 fpm climb from 750 fpm pre exhaust install. After discussing how to remedy with Art Mattison it was decided to procure a new prop with the Mattison tip mod from Sensenich ( see: and ) and keep the original for the hot and high density alt conditions giving me the poor man's variable pitch versatility on basic Cherokee. With this prop pitched to 62 and balanced I could still manage easy 850 fpm climb on a warm day at sea level with the added benefit of a lean of peak cruise of 130 + mph at 7.2 gph at 10,000 feet and still see 2700 rpm straight and level.

Point being: If you want to bring your O-320 ( or O-290 ) Lyc bird into the 21st century then FIRST a PowerFlow Exhaust system - that was hands down the best performance dollar I ever spent ( ) - THEN get the right prop - yep, this one.

And it won't cost you the $3945 advertised on Sensenich's's site and that's without the Hoerner tip style modification that increases prop efficiency allowing these numbers.

This prop has been well maintained and is untouched and never flown off a gravel or unpaved surface. The paint as you see it is original and I do not believe there are more that 250 hours on this prop as this was only installed half the time in cooler weather or for a longer trip. There is one tiny tiny ding on one side of the leading edge that was according to my A&P simply too small to be bothered with dressing.

Always follow these instructions for installation:

Interest and questions please contact me at