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has anyone built a 383 using stock tbi setup?

swampynthrcecort

swampynthrcecort

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Has anyone out there built a 383 using the stock tbi setup successfully. I've been trying to research it and have come up dry so far. Would this build require a new throttle body/ chip/ whatever else in order to make it run respectably well or is this a dream that will never come true? Any input is appreciated.
 
I haven't done this myself, but I know someone that has. To get it to run right they not only had to get a chip, but they had to switch to a 454 throttle body. Let me know if you need any more info.
 
You could run the engine with the stock tbi setup. But I highly recommend you visit the thirdgen.org forum and learn to burn your own chips. After reading a lot over there I swapped a computer 730 computer into my 1986 Camaro, now I'm already burning chips (flashing emulator actually). I'll be converting my Blazer to EFI next year too (already have a BBC EFI manifold).
 
As said above, check out www.thirdgen.org . You'll find all you need there. Your stock TB will be fine as it'll out flow your stock heads anyway. Bigger injectors would be needed and higher fuel pressure ( check out www.turbocity.com ). If you're building a really nasty 383 consider one of their bored high flow TBs.
I'm toying with the idea of building one too but using an Offy Crossfire manifold using twin dual injector TBs.
 
I have a 383 with throttle body injection. It runs great. I have Edelbrock performer rpm heads with 2.02 valves. I would recomend the big block throttle body. You can get a stock one or get the holley one that summit sells for a reasonable price. I have the holley one it flows 670cfm. I also have the larger red holley injectors in it. Howell engine management [810-765-5100] made me a chip for my motor. They also sell the throttle bodies and any other FI related parts you might need.
 
You don't need to swap sh!t. I had a TBI 406 in my old 90 2wd. The entire fuel, computer, and injection was 100% stock. Stock TBI heads, typical short block, but with 350 rods. Keith black pistons w/22cc dish, with those and the 64cc heads and the longer rods, had about 9.75 comp. IIRC. Comp Cams Xtrme Energy 268 cam. Had a noticable idle, didn't affect the computer at all. Check engine light never came on. I drove it for aboot 8k miles before I bought another truck and had to sell it. I have another 400 that I'm gonna do the same exact thing to, but with Vortecs. Oh the truck was a 350 auto.
 
So you reckon your truck was running fine with 406 cubes but using the fueling for 350 cubes with a stock cam? Fuel for a 200 horsepower motor can fuel a (potentially) 350-400+ horsepower motor?
I think we'll have to agree to disagree on this one.
 
southernspeed said:
So you reckon your truck was running fine with 406 cubes but using the fueling for 350 cubes with a stock cam? Fuel for a 200 horsepower motor can fuel a (potentially) 350-400+ horsepower motor?
I think we'll have to agree to disagree on this one.
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X2
I have a 400 with stock tbi heads, stock computer, and stock injectors. And I have to side with southernspeed, while it may run, it's not much better than the stock 350.
It needs chip tuning and upgrades in the injector section to reach its full potential.
 
The 406 would walk all over a 350. It was night and day difference. The 350 that was in it was still a strong motor, but no comparison. If your gonna run it at higher RPMs, then yes you need a bigger TBI unit. I didn't build it to runthe 1/4, just a quick driver. I drove it back and forth to DC every weekend, 4 1/2 hours one way, never had an issue. Almost beat a newer GT Rustang, but with 3.08s that wans't gonna happen. I was catching him, but then saw the upcoming redlight at about 125 mph, almost didn't stop...
 
I too have met people who run built motors on factory TBI, but I wouldn't recommend it. If you are building a mild 383 with a small cam and factory style heads you should be able to get by with bumping up the fuel pressure. If you are going to add more camshaft, significantly better heads, etc., you're going to need to start doing some PROM tuning to get everything running right. If you head over to thirdgen.org you will see what people have been going through to make the TBI's run. The 454 TB is not a direct replacement and requires some mods to work with the SBC stuff. I would recommend a holley replacement if you have the money, or doing the TGO "ultimate TBI mods" if you're on a budget. Again, unless you keep the cam small and the heads close to stock you're going to have to do some work. The wilder the engine, the more you're going to need to do. You don't want to damage your new engine because it's running lean. If you build a "nasty 383" and run it using the stock stuff you are asking for trouble.
 
i built my 383 using stock tbi heads, kb flat tops, stock vortec roller cam. I bragged right here on this sight about how great it was running and ignored every one elses advice. my dad was dying in the hospital 3hrs away. I jumped in my jimmy and got about 30 minutes in to the trip at 80 mph and #7 piston hit the plug. I have not torn it down yet, but experiance tells my that the top of the piston split off. It also has a knock now. I suggest listening to the warnings on this. If you build it don't be like me and try to be cheap. put a 96-97 vortec fuel pump witch boosts your preasure to about 45psi. buy a vacume adjustable fuel pressure regulater. And either learn to burn your on chips or find someone who is knowledable enough to burn one for you. You need the chip for timing more than anything else.

thats my 2cents worth.

I would not do it again the same way. I am going with a carb this time.
 
Say what you want, I know what I had, what I did and what it would do. Yes, it would have run a whole he!! of alot better if I did some computer mods, bigger fuel pump and adjust the regulator. If something was gonna happen, it would have happened somewhere in the 8k miles I put on it. When I first put the motor in, can't remember exactly, but somehow I got brass in the oil plug on the back of the block, and took the crank out. Then the flexplate cracked. First one was my fault, dunno bout the second, it was used, so maybe old age got to it. The guy that bought the truck beat the living snot out of it and finally blew it up. The cam that was in it wasn't huge, so maybe that is why it ran like it did.
 
southernspeed said:
As said above, check out www.thirdgen.org . You'll find all you need there. Your stock TB will be fine as it'll out flow your stock heads anyway. Bigger injectors would be needed and higher fuel pressure ( check out www.turbocity.com ). If you're building a really nasty 383 consider one of their bored high flow TBs.
I'm toying with the idea of building one too but using an Offy Crossfire manifold using twin dual injector TBs.
Click to expand...
twin TBI setup? I was just rereading all this making sure i didn't miss any important information and this caught my eye, i've gotta say, i'm pretty intrigued, how would you make that happen if you don't mind me asking? Unfortunatly in all my investigation since the only solid numbers i've been able to get was a 360-370 max HP out of a 7.4L tbi quote from turbo city. Not bad numbers, but i'm trying to get everything out of my stroker that I can while using a system i've already got most of the pieces to ya know. I'm really not trying to dump 3 grand to keep my FI.
 
You might want to search back through the archives and find the posts where people have burned pistons or the mix was so lean it was amazing the engine DIDN'T destroy itself before it was found to be so lean. It's a bit of a red flag assuming that a check engine light is imminent if the engine is running wrong.

Don't think I'm trying to pick a fight, I just really don't want people to learn expensive mistakes at their own cost.
 
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My 383 has worlds torquer 2 heads with 2.02/1.60 valves, holley intake, holley TBI, high pressure fuel pump, pretty mild crane TBI cam, heated o2 sensor, and some prom tuning and the thing runs like a champ. It took a couple tries to get the chip right, and it could still use a little tuning still but my motor does run quite well and Im happy with it. When I first built the motor for less than a week I had the stock tbi on there and no way in hell was it ever going to run right. It ran lean all the way around and no way would flow enough for the motor I had.
 
try tbichips.com they will take all the specs for your engine and burn a custom chip to your needs. plus they are located in the nc.
 
I run a pretty stock 383 TBI. This was actually my first major auto project, other than doing maintenance on my old toyota... I had to built it on limited funds, but I wanted to get the 383 rotating assy in the vehicle and do heads/intake etc later.

It's worked rather well.. I did the whole rebuild from pull to drop and the engine has about 7000 DD miles on it now. :)

I learned to make new chips (it's not that hard, but it takes time), upgraded the fuel pump, and shot 14psi into the stock TBI and injectors. When I has a hose fail in my fuel tank due to the much higher flow rate of the new fuel pump, a mechanic swapped in a stock chip and it still ran fine after he adjusted the fuel pressure.

It can be done, and a "stock" 383 definitely gives me more torque, but it's rather weak on the top end. Fine with me for now while I save for more power... but those are easy mods since the 383 is already in the truck.

The only components I upgraded besides the stroke itself were the cam, headers and fuel pump. Pistons are hyperuetectic (I hate spelling that word) SpeedPros.
 
swampynthrcecort said:
twin TBI setup? I was just rereading all this making sure i didn't miss any important information and this caught my eye, i've gotta say, i'm pretty intrigued, how would you make that happen if you don't mind me asking? Unfortunatly in all my investigation since the only solid numbers i've been able to get was a 360-370 max HP out of a 7.4L tbi quote from turbo city. Not bad numbers, but i'm trying to get everything out of my stroker that I can while using a system i've already got most of the pieces to ya know. I'm really not trying to dump 3 grand to keep my FI.
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2 stock style TB's on a crossflow Offenhauser manifold. It's basicaaly a low level tunnel ram developed for Trans Am series where they weren't allowed to have the intake sticking up through the bonnet...sorry, hood!!:rolleyes:
It's just something I'm considering doing on a 383. The Embedded Lockers set up would support this. It would be a lot cheaper to go with a stock TB and upgraded injectors/pump and the EBL or similar.
 
SnackPack said:
It can be done, and a "stock" 383 definitely gives me more torque, but it's rather weak on the top end.
Click to expand...
This one line tells the story... The reason that it's weak on the top end is that the injectors simply can't provide enough fuel to feed the engine. It's running WAY too lean. Lean burn = excessive heat. Excessive heat = melted pistons. You're risking your engine... :doah:
 
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