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Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

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Old Jun 29, 2016 | 11:42 AM
  #1  
Bald_eagle_machine's Avatar
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From: Chiefland, FL
Car: 1988 Trans am GTA
Engine: L98 350 TPI
Transmission: 700r4
Axle/Gears: Factory 9 bolt w/disc brakes
Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

Hey everyone,
First off I'll try to give all the details I possibly can to avoid any questions. I'm currently running a 1987 transfer am gta, with an lb9 and a t5 nwc. Car has exhause, egr delete, air pump delete, cold air intake still utilizing the maf system.

So I'm piecing to get her my new setup due to an injector issue, and I figured I might as well just upgrade whill I'm at it. So far I have these parts;

Edelbrock High Flo manifold
Edelbrock High Flo runners
Bosch 3 19lb injectors from Southbury fuel injection
Adjustable fuel pressure regulator
Ported plenum
52mm holly throttle body
All the gaskets and new bolts for the intake.

So I'm curious, what i's this swap going to entail? I know about the removal and replacement of all the parts... what I need to know, is how difficult will it be to set my fuel pressure? What tools will I need? Is there any special tricks and or tips to this swap. How will the car run without a tune? Any expert advice? Is the intake overkill for my 305? Should I just swap the injectors on the stock setup and call it a day?
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Old Jun 29, 2016 | 01:12 PM
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From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
Re: Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

Why are you swapping injectors? Car should have 19 pound injectors already....unless they're bad, and you need to replace of course.

I've never had extensive experience with the 305, but my guess is that what you'll notice isn't really power per se, but a higher RPM range. ...that does translate to being faster, because power won't fall off as quick, but will it really give you a seat of the pants punch??? Probably not. ....and the ECM should be able to compensate and run just fine, BUT....as with all things....any change you make can benefit from tuning.

As for fuel pressure, the screw on top is what adjusts the pressure. You'll need a gauge to plug into the schrader valve on the fuel rail. Then you just start the car, pull off the vacuum line and plug it, then measure your pressure and adjust as necessary. ...although many people would say that without heavy mods, leaving it stock is just fine. It'll save you a few bucks.

As far as actually doing the work, it's not too bad. Get a manual that shows the proper torque and tightening sequences, etc. etc, pay attention to where the distributor is when you pull it out. Stuff like that. Like all things, it takes some practice, but the only way to learn is to do it.
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Old Jun 29, 2016 | 02:07 PM
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From: Chiefland, FL
Car: 1988 Trans am GTA
Engine: L98 350 TPI
Transmission: 700r4
Axle/Gears: Factory 9 bolt w/disc brakes
Re: Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

This is the best responsored I've ever gotten on here, so I appreciate it.
The injectors are making weird noises, and occassionally it shudders while I drive it and the ses light comes on. I also believe they are leaking on startup, a's the motor slowly chugs to life on start up and sometimes the session light comes on when it really struggles. And for $150 from southbay, I figured why not.
Stock fuel pressure is 48psi correct? Will the Bosch injectors flow better then stock?
Also, I got the manifold and runners for a pretty sweet deal, so I figured why not swap them while I'm changing injectors.
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Old Jun 29, 2016 | 03:32 PM
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From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
Re: Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

Well, I'm glad I could help.

Stock pressure is 43.5 PSI. ...and you're right, for the price, it's not a bad piece of mind. Southbay is great to deal with. That's where I got mine. I think these are probably a good choice, but please double check with southbay when you give them a call.
http://www.southbayfuelinjectors.com...l-injectors-8/

....these use the adapters for proper fitment (My 30 pounders fit great!), and they're rated for 19 pounds at the proper 43.5 pSI, so you should be good to go.

....and I agree with jumping on a good deal. It's a great upgrade. ...later on, if you do heads and cam, it'll help even more, and if you ever get a bigger motor, again, you'll already have an upgraded TPI.
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Old Jul 9, 2016 | 07:22 PM
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From: Stafford, Connecticut
Car: 87 Iroc
Engine: modified 350
Transmission: high performance built 700R4
Axle/Gears: Strange S60 3:73
Re: Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

EGR is actually a good thing to have on a car it helps stop detonation which makes your car pull back timing.Thus you lose horsepower.It also gets you better gas miliage.
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Old Jul 10, 2016 | 12:00 PM
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From: Minnesota
Car: 1989 GTA
Engine: 5.7 TPI
Transmission: 700R4
Axle/Gears: 3.27 (Stock)
Re: Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

That 52mm throttle body may make the tip-in feel more lack luster. Way more than that motor needs, stock one honestly should flow more than enough still. Just a thought.
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Old Jul 25, 2016 | 12:02 PM
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From: North Central Indiana
Car: 86 IROC
Engine: 383
Transmission: TKO 600
Axle/Gears: 3.54 Dana 44 IRS
Re: Edelbrock High Flo tpi swap, afpr, new injectors, throttle body, ported plenum...

for what it's worth, the last 3 aftermarket throttle bodies I've installed have given me problems. I've put a couple BBK ones on lately and they have all required me to adjust the idle screw to open the throttle blades further. I love the BBK units, they are very nice, but they are almost completely closed out of the box, which won't yield enough incoming air upon startup. Turn the throttle stop screw in one turn at a time and see if your cold starts get better. Depending on how far you adjust the throttle stop you may need to re-adjust your throttle position sensor.

Also, I strongly recommend you port the Edelbrock base before you install it. Out of the box the Holley bases really aren't any better than the stock base. There is lots of good data on here about properly porting stock or aftermarket bases.

Last edited by 1MeanZ; Jul 25, 2016 at 12:05 PM.
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