Probably not new news here, but after upgrading my stock (131) delivery valves to 191's the difference is night and day. No more stumble with the 370 marine injectors below 1200rpm's. Im in disbelief how smooth it is below 1200. Takeoffs in 1st gear instead of low are awesome, and there is a definete SOTP increase in HP as well. Anyone on the fence, do it up you wont be dissapointed. Oo. Took me about 3 hrs on the install taking my time and being surgically clean around the pump and injectors. 
