You can get 100hp at the wheels easy if you have the money.
Do the flat top pistons from a 4.8, a 228r or equivalent cam, ported/polished 243/799 heads milled .025, with a cometic gasket with a compressed thickness of .030, adjustable timing set with -2 retarded timing, tbss intake with 50lb injectors from a 2013 flex fuel, with a 92mm throttlebody, or an LSXR truck intake with a 102mm TB, e-fans, long tube headers and a super-aggressive tune on 100 octane and you should be at about 370-390hp. Which is 100hp more than stock. But you'll have to do a 3500-4000rpm stall TC, shift kit, servo kit, trans cooler, and beef up the diff to take advantage of it. Or you could do a lot milder cam, like a 212/218 with all those mods and a 3000 stall TC with a turbo setup and far exceed 100hp.