Higher RPMs compared to what? You trying to pull OD at 1200 rpm or something?

Specs for '88 included here, no guarantee these are accurate, but they look right:

Engine_Specifications


A MPFI 5.8 shows 210 hp at 3800, 315 ft/lb at 2800.

HP and TQ peaks at higher rpm than the 300 six, but with more of both. If you had a dyno readout you'd probably see the 351 makes about the same or more HP and torque at those lower revs than the 300 does. (you think it gains 60 hp in 400 rpms, for example, or that it gains 55 ft/lb in 800 rpms?)

Compared to a 460, the peaks are 3600 for 230 HP, and 2000 for the 390 ft/lbs torque, so yes, the 460 is going to have LOTS more low end than a 351w, but you'd expect that.

2800 is hardly "high rpms" for a gas engine. 3800 probably sounds high, but you still have 290 ft/lbs of torque at those revs, so it should pull nicely from 2000 rpms up, and depending on your transmission ratios, you could probably run it between 2400 to 3400.

That's not to say that the 351w is powerful enough for your application, maybe you need more motor.