I am having my dealer do an engine upgrade , 1550 kit with 258 cams any postives or negatives on these cams. Have new heads put on to # 16952-06 .

 

I think you're throwing 40% of your hard-earned money down a rat hole, but hey, that's just my opinion. Try doing a search on "horsepower" or "heads" on this forum - or just call HeadQuarters, GMR, a trusted independent where you live, or any one of the builders and compare what they're offering. Would you marry your girlfriend on the first date?

 

I've got the 258's in my 01' Ultra. I've got the SE heads, 1550 kit with the forged pistons. My compression is around 185psi with these cams, and I have had pinging problems until I retarded the timing in the problem areas. The 258 cams are high speed cams and make there power at the top end past 4000 rpm's. I get decent performance on the low end, but I will be changing my cams to a low or mid-range cams soon.
You'll be better off by staying with some low end cams like the 204's to keep the torque at the bottom. Also, don't try to get crazy with compression increases or you'll have detonation problems.

 

i agree,had the 258's installed with the se hi-compression 95 inch kit(heads as well)
and never was happy with overall preformance.had a set of 203 put in for now and have tons of ridability,getting about90 horses with 105 tourque using the power comander3 USB,
gonna get a sert and a slightly bigger cam.do some serious research,its cheaper in the long run!

 

thanks guys i really appreciate your feed back...

 

I had 258 cams, SE hi perf heads, hi comp forged pistons in my stripped down road king for 4 years, 50,000 miles, and was happy with the performance, I have the motor apart now, (valve seals leaking). Going back together with the Hippo build.