(gt35/40 1.06 a/r) VS (gt40 .82 a/r with t3 flange)

[caterpillar]

think its like this( the gt 35= gives only 500-550hp) but you may take it for more rpm( a/r 1,06).....like 8000rpm+
and the gt 40( gives about 600-620 hp) but will end earlier, like 7500rpm or lie this
when the boost are coming, are the EM and IM who desides...( big turbo= longer tubins, for the EM, and you may have "bigger" cams.
and the ccm( you may use the gt 40or the 42 with 0,94 a/r... instead) spec if you use the 2500stroker(2700ccm...)

what can we say about these 2 turbo's if we compare these?

when does the boost start?
when do we have max boost?
what hp can they give?

can any one tell me some about these turbo's