help, 90 blazer tbi to carb?

[low 84]

trying to help out a friend at work. he has a 90 blazer with 8 or so inches of lift and 37's on it. he is planning on putting a zz4 in it and going to a carb. the thing we don't know about is the in tank fuel pump for the tbi. i know it puts out too much pressure (aroung 14 psi) for the carb. if we go to a mechanical pump on it, what kind of sending unit do we get that will drop right into the tank inplace of the factory in-tank pump. will a sending unit from like a '85 q-jet equiped blazer drop right into his tank?

[Captkaos]

Just run a fuel pressure regulator and drop the pressure down to around 6 lbs. He does realize EFI is better than a carb right? Why is he changing?

[low 84]

well he is going with a zz4 crate motor. the tbi won't really handle this motor without computer tuning and burning of custom chips and even if thats done tbi's don't even flow enough air to support it at its peak hp levels.

so the in-tank fuel pump will function fine with all the other tbi accesories removed? just needs a add a regulater in line to cut back the pressure to 7 psi or so? is it okay for a regulator to cut the psi that much, from 14 down to 5-7 psi?

[67_SS396]

I thought they were higher pressure, but I'm not sure. Yes, the regulator will work fine. For example, I'm running a Holley Blue electric pump and it pushes 14lbs un regulated. With the regulator, I set the pressure at the carb to 6lbs.

[low 84]

Originally posted by 67_SS396
I thought they were higher pressure, but I'm not sure. Yes, the regulator will work fine. For example, I'm running a Holley Blue electric pump and it pushes 14lbs un regulated. With the regulator, I set the pressure at the carb to 6lbs.

sounds good! thats what we'll do then. i have become a little familiar with tbi in the past month. i helped of friend with the mechanical end of putting an lt1 roller cam and early 90's L98 camaro heads on his 91 tbi 350. he took care of the electrical part of it though cause thats not something i wanted to mess with. we put a fuel pressure guage on it and it runs a steady 14. we looked it up and thats what they are supposed to run, which is much less then most other efi setups for some reason........

but now looks like i'll be helping another friend doa zz4 swap into his blazer, i think the fuel pressure issue was the last thing that we needed to clear up. now i'm just wondering how we are gonna get a motor in and out of a truck with 9 inches of lift and 37 inch tires

[Jonboy]

pull the front tires, or just air them down all the way. The last time I put an engine in a lifted truck, I pulled the front clip. I did the engine, trans, and transfer case as a unit, though.

[Grim Reaper]

Originally posted by low 84
well he is going with a zz4 crate motor. the tbi won't really handle this motor without computer tuning and burning of custom chips and even if thats done tbi's don't even flow enough air to support it at its peak hp levels.

so the in-tank fuel pump will function fine with all the other tbi accesories removed? just needs a add a regulater in line to cut back the pressure to 7 psi or so? is it okay for a regulator to cut the psi that much, from 14 down to 5-7 psi?

Need to find a Thottle body and computer off a 87-89 454. It will handle it. It's a bolt on to a spread bore pattern

For a 4x4 if he plans to wheel it he should stick with the FI. Nothing sucks worse then getting on a steep hill and having the carb stall out and not re light. I have 454 FI sitting on the work bench I'll be installing on my 75 Trail K5.