I have just installed one of Hals 104 hp kits, this is an amazing upgrade,.
A few questions
1 has anyone done a before and after cranking compression test, my pressure is 145 psi I didn't do a before upgrade comparison.
2 the reason I am asking is we weren't happy with the amount of valve shrouding with the stock 80 hp heads, does everyone leave these as stock?
The heads were cnc machined to be more like the 100 hp heads, this requires a small cutting of the heads to restore stock pressure.
This was a bit of an educated guess ,also valve geometry was taken into accoumt.
BTW we set the ivo 72 inch prop to 5100 static with the original setup. After the upgrade I could easily exceed 5800 after an hours breakin
I'm looking forward to getting some more testing and solid performance numbers