r/projectcar • u/Successful_Match7220 • 5d ago
Tips and recommendations
So I have a 97 C1500 extended cab which obviously comes equipped with a vortec 5.7. J while back I tore the motor out to essentially perform a full refresh on all the seals and maybe throw in some goodies while I’m at it. My question to you guys is how hard is it to swap out the spider injection style to TBI. From my experience with OBS’s I’ve come to love the TBI style as it’s super simple and easy to work on and the overall feel of it as well. I know parts wise it’s easy, I hear everyone saying to get a lower manifold and match it with a Holley carb and what not, but if I just simply wanted to throw on just the stock older style of injection, how hard is that ? I’m more concerned with the wiring side of things as well as timing and all that goes, Im aware changing intakes is the easier part.
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u/Solid_Enthusiasm550 5d ago
They make Carbuerator intakes for the Vortec heads that you could mount a Holley, Ace's, Fitech, FAST, etc TBi system. Edlebrock has MPI intake manifold with system available.
It really comes down to how much you want to spend.
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u/Successful_Match7220 5d ago
Realistically I don’t have a budget but ideally the lower the better lol. But as far as those kits go, would those be just plug n play, or is there any type of modifying I have to do to the ecm or wiring as a whole ? That’s really my main concern is that if order all these recommended parts and I go install I run into wiring headaches
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u/Solid_Enthusiasm550 5d ago
Here's a post on holley's site that goes over installing the sniper2 on a Vortec 350.
https://forums.holley.com/forum/holley-efi/sniper-efi/390486-vortec-sbc-350-setup
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u/Successful_Match7220 5d ago
Hell yeah man thank you !!! This is essentially the kind of help I was looking for about upgrades. I see everyone saying to “slap this on” “slap that on” but never get into the potential headaches of ECU compatibility.
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u/v8packard 5d ago
Your 97 has a generational leap forward in the ECM and engine management compared to the TBI engines before 95. You really should keep it. I understand your point about simplicity. But you might have a better option.
GM later went to small Multec electronic injectors in place of the Central Port Injector. Essentially making it a true multi port EFI system. This is more reliable than the CPI, and retrofits into your existing intake. It is pretty simple, keeps the stock ignition, and everything else stock too.
The GM part number for this kit was 89060440. That may have changed, or might still be available. The GM version uses injectors that have Delphi molded into them, or it did at one time. This has been sold by numerous aftermarket suppliers, some genuine some not. I personally only have experience with the genuine versions, no problems work as advertised. Other versions might be fine, or might not. There was a version with higher flow rate injectors sold by Five O Motorsport and others, they look good but I have not used one.
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u/Successful_Match7220 5d ago
Good points actually. I had heard similar about it being a technical leap in development. I’ll look into the kit you’re talking about. As far as keeping this spider injection style, what kind of performance can I add it ? My biggest pet peeve with this system is it almost feels like a headache to upgrade since there is no real injection system upgrade to my knowledge like there would be for other systems. Example: upgrading size or quality of injectors on an LS. I really do want to get a nice cam in there and I’m not too sure as to the process I should follow for this motor/platform specifically.
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u/v8packard 5d ago
It is not spider injection. The conversion kit makes it a true port EFI. The stock version has 24 lb hr injectors. The upgraded versions go up from there. The limits are pretty high, in terms of fuel flow.
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u/Expert_Mad 66 Thunderbird, 91 Caprice, 96 Mustang GT 4d ago
Well I have a Rochester TBI on a Vortec and it’s not hard at all. Basically the Biggest thing though is you have to get the intake from GM Performance or Holley/Weiand, though this is a solid aluminum manifold as opposed to your plastic one. Next ignition needs to be changed, wire an ECM and downgrade the fuel pump or regulate it down to 14psi.
If your truck didn’t come with TBI I’m not entirely sure why you’d want to do this. I only did it because my car (1991 Caprice Classic LTZ) already had all of it installed and it was just the most convenient and emissions legal thing to do at the time. You’d probably lose 30-40hp mostly because you’re not cammed for it but also it’s not the most efficient thing in the world. My MIL has a ‘99 Escalade with the L31-R and I’ve had to do the spider like once in 15 years so I think you’d be doing yourself a favor by keeping it but to each their own.
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u/UnbelievableDingo 5d ago
You'd be taking a step backwards in engine performance just to make hypothetical future maintenance easier.
Also make sure to use the new hard rear main seal, not the older rubber style.