My engine makes around 690 to 715 hp depending on how good or bad the air is, 12:1 compression, .750ish lift 270/280 duration. 240#'s on the seat 650# open springs.
Its not bad maintenance wise(my opinion of course), and has spent 99.5% of its running time on pump fuel. I did a few dyno pulls on ms109 to see if it would be worth running race fuel. I made 10rwhp and 5rwtq more than pump gas. 582 rwhp on pump, 592 rwhp on race fuel, not worth the money unless i need another half a tenth on dragweek or something. I do think there is more power there with e85 but at the time the stock lines on the car would not have supported the volume.
As far as maintenance goes, i dont go more than 750 miles without checking the valves. Now, 750 miles doesnt sound like much to some people, but with these cars not being driven if rain is in the forecast, sometimes it will take a month to put that kind of mileage on it. Which is what i would say, on average, is how often i go thru the valves. Now that i have done it a bunch of times, and have a bump button, it takes about 15-20 minutes to go through them. I also use a LSM tool to check the springs while i am there.
Now onto the wear items, lifters and valvesprings. Lifters... buy good ones, spend the money on a set of iskys or morels. I use isky bushed lifters, there are varying opinions on bushed lifters but i feel in a street engine they are a good idea because there is no risk of needle bearing failure running thru the engine. My maintenance plan on those is every other winter they come out of the car and go to isky for a checkup. I had around 2000 miles on them and sent them to isky, they said the lifter was still within the tolerance of when they were originally produced. Sending them to isky is more of a sanity check for me. Valvesprings... again, buy good ones. I have had good luck with pac's. I went 3000(hard) miles(two dragweeks) on them and found a broken inner spring after dragweek 2015. I spent alot of time on the limiter during dragweek and i think that may have helped the inner break. Now the maintenance plan is to replace them every winter. In the big picture of this engine, 250 bucks for a set of springs is a drop in the bucket and it is about a 4-5 hour job by myself to swap them out.
I had a lengthy conversation with my engine builder about going to a hyd roller cam, ill spare the details but it ended with him saying, "If a lifter rebuild and a set of springs is the cost of being the man, well...."
