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Carbed 383 to Fuel Injection

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bacon310

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Hey guys im new to the 4x4 game and i need some advice. I had a 383 stroker carbed in my 64 el camino that i traded for a 1991 K5 Blazer. I want to drop that engine in my truck, how hard is it to go from a carb set up to a fuel injection set up on the engine itself since the truck is already fuel injected? Any help or reading material would be greatly appreciated. Also i havent been able to find a repair manuel for my vehicle, i wanted to throw all the emissions stuff back on it since i live in Commifornia.

Bacon310
 
TBI can be difficult to get to mesh with some cam profiles. Since you built the motor as a hotrod piece a stab in the dark would say it wouldnt be a bad idea to tame out the cam a little bit. What cam is in your motor?

O and that being said the most a TBI is going to feed is in the ball park of 400hp.
 
the cam is pretty big, i need an external air pump to create vacuum for the brakes. i can deal with 400hp, i just figured since i have the spare engine already built and dressed i might as well drop in the truck.
 
Yeah I would highly recommend you take a look at a tamer can. Not only because its a truck application now but TBI will 100% required to be tuned and it won't be via mail order with a cam like that and it isn't the easiest to find a local for these apps anymore.
 
bacon310 said:
the cam is pretty big, i need an external air pump to create vacuum for the brakes. i can deal with 400hp, i just figured since i have the spare engine already built and dressed i might as well drop in the truck.
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EFI generally likes at least 110 lobe separation... that mill has WAY less than that..... it can be done, but it would be WAY easier to do a cam swap first...
 
ryoken said:
EFI generally likes at least 110 lobe separation... that mill has WAY less than that..... it can be done, but it would be WAY easier to do a cam swap first...
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Did I miss it? But I didn't think he told us what his cam specs were...

ktmoutfront said:
Fast EFI, EZefi and some of the self tuning systems would probably be easier.
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This is the way I would go(in fact I did), but as mentioned you should still swap the cam to a fuel injection friendly cam (if you don't have one) but the correct cam with a fast setup you still can have 400plus horsepower....
 
beags86 said:
Did I miss it? But I didn't think he told us what his cam specs were.......
Click to expand...

I don't need to know the actual #, if it doesn't make vacuum, it doesn't have close to the LS to run EFI..
 
Even if you went with FAST, you still need at least 8" of vacuum at idle for the system to work properly.
 
a 355 is surprisingly just barely over stock,:wink1:, no surprise it makes 15" at idle. I would hope it does, no matter with stock or roller lifters.

it's exactly how mine was rebuilt as well, bored over a bit, roller lifters installed, still using all other stock equipment. :tongue1:
 
Since this truck originaly came with TBI injection, I am going to assume we are talking TBI here?

1. TBI uses an OBD-1 ECM. This ECM needs to have a cam with no less than 112 degress of Lobe Seperation (110 lobe seperation will cause a problem). Anything less than this causes vacuum signal problems with an OBD-1 ECM.

2. You will need more fuel than stock TBI injection system delivers because of the increased cubic inches. For this you will need a modified factory TBI, which is bored out to about 2" or 2-1/8" DIA, incresed fuel pressure, higher performance fuel pump, and a bored out TBI manifold to match the modified TBI injection diameter.

3. You will need a custom burned ROM chip for the OBD-1 ECM

4. Also is this engine a PRE-86? or PRE-86 heads? These heads have a different intake manifold bolt angle in the center four bolts of the intake manifold. If you do Holley makes an intake manifold for these PRE-86 engines.

P.S. a 3-wire self heated O2 sensor would be a good thing too.
 
4xcrazy said:
a 355 is surprisingly just barely over stock,:wink1:, no surprise it makes 15" at idle. I would hope it does, no matter with stock or roller lifters.

it's exactly how mine was rebuilt as well, bored over a bit, roller lifters installed, still using all other stock equipment. :tongue1:
Click to expand...

Well my cam really isn't that radical. Its a 112 LSA with 219/228 duration @ .050. I feel like its matched pretty well for the truck.

Sorry OP, don't mean to hijack.
So basically for you to run the engine in question, you'd have to cam swap and still do a custom chip with supporting fuel system upgrades, or you'd have to retrofit a TPI system or go with an aftermarket EFI system like FAST.
 
vacuum production is pretty much a function of duration.. and duration tends to go hand in hand with LS, at least with flat tappets... thus duration to have no vacuum, generally means a LS, FAR from being EFI friendly...
 
If it was me, and this 90 K5 runs real nice, I'd sell the 383 for beer money.:D

Or at least sell it and put it towards an LS swap fund. Not sure how the LS swap deal works with smog though.
 
My intention is to just have a beefy engine in case i need the extra push, i have all the intention of putting the smog pump egr and all the emissions equipment back on it. The only real problem im running into is finding a C.A.R.B. compliant intake manifold for the engine.
 
building a 383 stroker TBI engine is no small feat. It takes a lot of planning. You should just get yourself a direct replacement GM Goodwrench crate engine. The one that came in this vehicle goes for about $1700 with free shipping from jegs.com. The Edelbrock TBI manifold for this engine is 50-state smog legal. Comes with EGR provision. I do not think a centerbolt (non-vortec) 350 came with a smog pump.
 
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