I haven't been following this whole discussion but caught the gist of it, I
think, and hopefully am not repeating too much here.
There are many books out these days on the GM fuel injection setups and how
to retrofit them; I believe Chevy High Performance had a major run on them in
the last year or so.
While I'm probably the biggest Corvette fan on this list and have one of the
TPI Corvettes, what I've read makes it clear that the Camaro units are much
better to use for conversion. A used unit is much cheaper and there are
custom components/mods on the vette units and complicated controls/instrument
interfaces that would make them difficult to adapt. My brother Brian briefly
considered TPI on his 85 pickup rebuild but decided to go with a carb at the
last minute mostly due to dollars. I've also considered it for my 86
Siverado which is started to limp due to its 205K miles.
Things to remember:
The original TPI unit was designed for a 305 instead of a 350 so the flow on
the stock intake on a 350 makes for good torque at the low end but not so
great at the high end. I know as this is what I'm running; makes a great
autocross car on tight courses but I lose if there are long straights. I
would think that this setup would be good for trucks though with all of the
good low end torque.
The other item is that this h/w is not forgiving of engine mods if you use
the later higher hp speed density system like on the LT1's (which are also
high rpm hp engines). Reprogramming the EPROM is necessary. The earlier
mass air flow (MAF) based systems are inherently more adaptable to engine
mods and even adapts to driving styles over time. Reprogramming the EPROM
might be suggested but I suspect that it might not be seriously necessary.
GM eventually went back to the MAF approach; the change to speed-density was
based on cost, not on performance. So the early TPI MAF based systems are
better for retrofits in my opinion.
Probalby the biggest pain is that the TPI needs a high pressure fuel pump; GM
puts it in the tank. . .I assume but don't know for sure if it has to be
there.
While gear ratio and weight have to figure into the equation, gas mileage
efficiency is also great on these setups. I get 27mpg on the interstate at
70mph on mine; net hp was 245 and I have a very free flow exhaust on mine. I
think the vette weighs about 3800 lbs so it's no light weight.
Mark Noakes
Knoxville, TN
58/56 Suburban
86 Corvette Indy
86 Silverado
66 Corvair Monza
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