how much water pressure can i safely run? the 38 that monstaa posted looks like a lightning. are the bottoms on a fever any different from a lightning?

2001 was the last year for the Fever - up to that point the lightnings and fevers shared the same bottom.

As for water pressure I was running around 25 psi at wot with the sportmaster drives. When I switched to the imco's it was reading off the guage which went up to 40 psi. One my second run it blew a hose off so I put it up for the year and had strainers and pressure relief vales installed that winter.

you should be rite around 20 psi at w.o.t . this will save your intake and head gaskets. if you run higher pressure under normal conditions when you spike the pressure, like during rentry, you WILL rupture , blow, or pop something off.
as margin said stainers with pop vavles, and air bleeds in the strainers are a must when reaching trhose high numbers.

I run 1" shorties on my 99 38 Fever... no issues. You could go with 2" shorties and add back a spacer if needed. I see 98 MPH without ever having touched the props... the acceleration is like a drag boat with 750 COBRA's. Ratio 1.35 Props 26 P Hydro 4 blades.

most people do not check there x dimension before swaping lowers, which helps to determine which length would be proper for that application.

some boats came with higher x's, therefore some have experienced major p.s.i increase when going to shorty's due to the fact that the pickup on the imco's is right at the begining of the bulet on the bottom and is about the size of your lil pinky. this causes the water to just ram in. throw into that the increase in speed from said swap and you gots big pressure.

moral of the story watch the gauge.

i wish i would have bought 1.35 drives instead of 1.5s. i could have just used my stock props!

are my imco uppers and lowers much stronger than xrs?

not really the are the same gears essentially. i have been enformed the the imcos have more strength . but i know they both buy from the same manufacturer . imco is supposed to be freezing their gears which helps the integrity of the gear itself. but i can not say for sure.

my experience with both units have been good and have similiar failures. although imcos due blow easier when you spin your engine over 6000 rpm for extended periodsd of time which decintegrates the bearings for the prop shaft and the grendade. i have seen this atleast a half dozen times.

ran the boat with the -2 shorties and 30 bravos. at 3500rpm 52mph, 4000rpm 56mph, 4500rpm 62mph, 5300rpm 86mph(rev limiters). i hate the mid range slip but the top end hookup and acceleration is amazing.
the boat handles sloppy water way better than the stock bravos. i think because i need way less trim.
i'm thinking of trying 32 bravos and 1" spacers or 5 blades. input is appreciated

the pic above is of -2 shorties and max 5 blds. handles slop and ruff like a formula one car.

i d try the 32 with the shorties.

and if you can find em 5 bld 30 max's