not if you got a 99 3L long block you would get split port heads instead of oval port, dont know about the oil drains and all that(if they have the extra like the oval ports do) and dont know if they will give as good of performance as a set of oval ports(have to talk to demon on that one) but it would save you having to port the heads to match them to your LIM

98.5 Black SE ATX S&B filter, SVT MAF, optimized SVT TB, mesh grille, removed orange reflectors, painted rear reflector, gutted pre-cats, optimized SVT LIM, 19lb injectors, resonator removed cant afford an svt but lookin for 1 in nc