I'm looking to purchase a 95 31 foot with twin 454 Mags. The engines are stock except for Imco exhaust. The boat's currently equiped with 23 Mirage 3-blade props. What top speed should I expect?

I do say 60-65 mph rang !!

I had this engine setup in twin 454MAG in 28" Scarab with 25" Mirage @ 4800 run 108kmh.
now with 502EFI with 26"Bravo@5000 run 118kmh and with 27"lab Mirage @5000 run 121kmh.

I own a 31 scarab with twin small blocks.......(I know, weird combo, 425 plus HP cause I built it). Anyways, I run 70-71 on GPS, and there is an identical one that has the 365, or 385 mags, and we've run a few times. I say he runs about 60-65, like Mike above.

Here are a few I know of:

1991 - carbed 502s - 385's I think - runs about 68 - 70
1994 - carbed 425 small blocks - runs about 70
1994 - carbed 502's (about 500+ HP) - runs about 78
1992 - had 502 efi's - ran about 68-70
1992 - (above with rebuilt engines) - runs high 70's still needs to be tweaked
1991 - larry smith flat deck, about 700 HP, runs about 90.

These are all GPS numbers.

my 96 31 with 454 385hp mags ran 67-68 gps(I did see higher a few times) all the time..no matter the load....fresh water 25p 3 blade mirage, at only 4500rpm