L31MaxExpress
I'm Awesome
as a guy with a way way over built 454 TBI burb I say swap a junk yard L94 out of an escalade including the whole computer and wiring harness, few grand and a few hard weekends work plus time messing with wiring =403hp & 417ft-lbs, or to get any power out of the TBI the motor needs to be pulled and rebuilt, shaved deck, new full performance heads, cam, push rods, rockers at the least, the throttle body and ignition really limit any top end and the CPU's are untunable so getting a chip burnt is just guess work on how the motor will function but it would do fine for towing, you'll get ~350hp ~400ft-lbs for $4000 as a guess but won't have to mess with wiring
Also a few tips if you do rebuild the 454 in your burb:
1.)don't try and fit long-tube headers on, I have them on mine, not worth it, had to drop the engine in without them, unbolt the passenger side motor mount, hoist the truck, hoist the motor to sit on an angle then pass the passenger header from below. Then had to do it all over again cause their isn't enough room to get a mini-hi torque starter in with them in & its hard to not burn through plug wires
2.)don't put tall valve covers on, they rub the passenger side firewall, I took a hammer drill to a small area on my firewall to give it clearance so it wouldn't pop the valve cover bolts out when I floor it, looks ugly but works
L94 is a dog. I used my uncles direct injected 6.2 to pull my trailer just because he raved on how strong it was. Was not impressed at all. I wouldn't use to pull a utility trailer if it did not have a positive displacement blower on it. All rev and no grunt.
TBI can be real time tuned without touching a chip. It also will not hamper top end power to any degree. They make 54mm bored TBI units and those are way over 750 cfm. If that is not enough you can go to a 1:1 linkage 4bbl throttle body with 4 x 120 lb/hr high impedence injectors. Stock small cap HEI works well past 7,000 rpm if you use a DUI module or MSD 6A box to get the coil charged with the limited dwell time available at high rpm.
Look at what Mercruiser did with the 575SCI. Dual 454 TBI units on a blower on a 502 and it had 575 hp @ 5,000 rpm and low boost. Pulley them up and add a decent charge cooler and they reliably gain 100 hp or more.