L31 is a good idea, but the TPI intake for it must be made of gold because it is very expensive. vortec intakes in general are expensive $400+ canadian the last one I bought for engine replacement I did in a boat this past spring. The $2500 was in Canadian dollars, so $2000 us. But yes expensive... there are many reasonably price aftermarket heads these days. it is the route i would go personally. I did the TBI heads as an experiment more than anything. mainly internet myths that you cant go over 10:1 with iron heads on pump gas. i'm 10.3:1 and ran 89 all summer with zero issues once i got my Qjet and advanced dialed in. it shocked the machine shop, especially when we dropped the all in timing from 32* to 26* and it picked up 15hp and 20ft-lbs of torque! SBC can still make power, don't let the keyboard mechanics convince you other wise.