Improve the TBI 454 or go 8.1?
 

I have a 89 GMC Dually with a stock TBI 7.4. It does have headers but would I be better off changing the heads and intake to a 049s I have that are ported with big valves and maybe a camshaft and stay TBI or I also have a 8.1 complete with a 4L80E that I can get a harness from Nordstrom for 875.00 to run it all. Thanks!

dont waste ur time or money on improving a tbi, put the 8.1 in