1998 5.7 AIR INTAKE MANIFOLD

[RobCole 96stepside]

I have a marine intake setup if you're interested in a semi-stock set up. Cast lower, aluminum upper complete with fuel rails, fuel regulator and 8 injectors as well as 8 injector connectors. Just bolt on your stock throttle body. Or you can get a Holley 300-263 vortec style intake as a starting point for an aftermarket conversion. You'll need an EFI elbow to accept a new 4 bolt throttle body and new injectors as well as connectors and fuel feed connections.

I’m trying to run that intake. The 300-263. Did you find a way to connect the factory wires controlling the injectors to the aftermarket injectors. I figured if that was possible, the stock computer can still run this intake.

 

[L31MaxExpress]

I’m trying to run that intake. The 300-263. Did you find a way to connect the factory wires controlling the injectors to the aftermarket injectors. I figured if that was possible, the stock computer can still run this intake.

The harness I used has gone way up, but when I bought it for less than $30 from Summit an AEM V8 injector subharness was a steal. The wiring is pretty easy. I wired my OEM injector wiring into a matching Deatschewerks connector with the injectors pinned appropriately. Each injector gets 12v power from the pink wires and each injector gets an individual ground from the PCM at the spider connector. I have added 2 injector wires to V6 harnesses, moved the injector pins around at the PCM and made them V8 harnesses too on Astros and S10s.

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[L31MaxExpress]

The pacificp and ppediesel threads are inaccessible even though they pop up on the Google machine. They had a lot of good info and Hog claimed noticeable gains from 3000+ over stock. The 3 bolt intakes like I have are apparently impossible to find anymore. But the real appeal to is, at least for me, was the fact that the Whipple would fit it and allow the use of normal injectors. We're I to be NA, the Ramjet would also be a decent, albeit not cheap, option. They even quit making the plenum spacer so your options are pretty limited. With a stock motor though, there is cheaper lower hanging fruit.

Do not need to have a 3 bolt unit unless you need to bolt a whipple to it, lol. The 4 bolt ones will work with the stock throttle body using a 4-3 bolt LS throttle body adapter. Most guys put a spacer for the cruise peg to clear the fuel rail. On the van that was not an option, so I bent the cruise stud arm up above the fuel rail.

 

[RobCole 96stepside]

The harness I used has gone way up, but when I bought it for less than $30 from Summit an AEM V8 injector subharness was a steal. The wiring is pretty easy. I wired my OEM injector wiring into a matching Deatschewerks connector with the injectors pinned appropriately. Each injector gets 12v power from the pink wires and each injector gets an individual ground from the PCM at the spider connector. I have added 2 injector wires to V6 harnesses, moved the injector pins around at the PCM and made them V8 harnesses too on Astros and S10s.

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You are the first real lead I have!! Everyone wants a million dollars for the marine intakes for our engines. Now that Holley makes that intake (300-263) for the vortec I figured if I had the wiring diagram people use for the marine intake, it would be wired the exact same way as the Holley one. So I understand you said pink would go to all of the injectors to give power. The other wires are grounds you said as well. I’m guessing the right ground has to go to the right injector so that it fires at the right time.

That’s what I’m trying to find. Which wires go to which injector. I’m going to try and look for the AEM harness you were talking about.

 

[L31MaxExpress]

You are the first real lead I have!! Everyone wants a million dollars for the marine intakes for our engines. Now that Holley makes that intake (300-263) for the vortec I figured if I had the wiring diagram people use for the marine intake, it would be wired the exact same way as the Holley one. So I understand you said pink would go to all of the injectors to give power. The other wires are grounds you said as well. I’m guessing the right ground has to go to the right injector so that it fires at the right time.

That’s what I’m trying to find. Which wires go to which injector. I’m going to try and look for the AEM harness you were talking about.

This was my GM to AEM notes. The left side is stock GM layout on the spider plug. The right was for the plug on the AEM harness I used. As I mentioned earlier all the pink wires are power and join two splices a few inches into the main wiring harness bundle.

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[L31MaxExpress]

This is the harness I used. Most other vendors have it around $150 now. Why they have this listed as a Ford harness I dunno. The spacing for the injector connectors works well on a SBC.

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[L31MaxExpress]

This was the connector kit I bought. Plenty of spares to use for other stuff.

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[L31MaxExpress]

I have had a set of these for a while as well. They make a nice crimp for many different repairs. They crimp the Deatsche pins in a single motion, both the conductor and insulator crimps. Also use them for the solid sleeve style. Solid crimps that are not going anywhere anytime soon.

https://www.amazon.com/gp/aw/d/B08DRCRRCQ?psc=1&ref=ppx_pop_mob_b_asin_title

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[Erik the Awful]

Ooh, nice! If I needed a crimper, I wouldn't hesitate to click that into my Amazon basket. I paid more for my crimper that only does the factory-style crimps on the right in the pic above. Plus, it comes with a wire stripper.

 

[Pro439]

So you can get the connectors and pins from efi connection or custom connectors. I bought the Holley injector harness and repinned the connector to connect to the factory harness. And yes now the marine intakes are as much or more than an aftermarket intake. When you get injectors you have to keep in mind that gm runs there setup at 60 psi and most of the aftermarket are rated at 43.5 psi if you buy the ones rated for the lower psi and run them at the higher psi they will be to big for what you have. And that only matters if you’re using the stock computer as all the fuel tables are for the higher fuel psi. If you are going to use the stock computer you will have to provide ports for the map and evap sensors. I’m doing this on a 7400. I had to get a different distributor as the crab cap puts the plug wires right into the fuel rails and there is not a different cap option