Yes I agree with this statement. In simple terms the TBI has such small parameters any changes out of stock need either a custom chip or a custom tune.
I put a vortec bottom end in a 89 k1500 with the vortec cam and have had issues with running rich, and backfire on decceleration, just very slightly.
im in about the same boat- pulled roller cam from cop car caprice lt1 (almost identical to truck vortec cam), cut some metal out of the intake runners and swirl bumps in the stock heads, some more out of exhaust ports, flat top pistons, roller tip rockers with a bit more lift, bored intake and throttle body, spacers on throttle body and injector pod, pressure reg, blah blah blah...
runs pretty good on the stock chip, maybe just a bit rich, and occasionally can hear it pop out the exhaust when deccelerating and the motor is cold (but the a.i.r. prob doesnt help)
no idea what kind of power it puts out, definately feels better than before (went from 31" on 3;08 gears to 35" on 3:73 gears at the same time)next time ill abort the stock heads- you can definately feel the power drop off in higher rpms...
about 40K miles in the last 2/3 years and running strong with only a water pump and oil pressure sender replaced.
-would prob feel way better with a proper chip tune and better gearing... when its in the dirt and the tires can slip a bit, or its in low range, its sooo much fun. its been more power than i need, and not quite enough to blow up major components
and got 14mpg on the highway once driving like a grandma on the freeway (on 35s with no overdrive)
AND passed cali smog test twice this way, so no real complaints i guess.
tried a chip from brian when i got it all together- just a bit more power, ran REALLY HOT though! scared me enough to not try mail order chips again- radiator and heater core both blew and got replaced before i went back to the stock chip...
ill do it myself if i ever have the time or notion.
