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I have a 1998 Vortec 350 I just pulled out of Z71 pickup. It has all the fuel injection still on it. It has 179K miles on it and assuming it checks out after tear down and inspection I would like to rebuild it and keep the FI. What H.P. and torque can I get from it and how would I go about getting it? I would like to put it in a late 40's early 50's Chevy truck.
I don't know squat about EFI, but you are starting with the best Gen I block and heads that are available in my opinion. Long-tube, equal-length headers and a mild cam to match the static compression ratio would be about all I would be able to add. And even at that, I wouldn't know how to tweak the EFI to make the changes work. Use a cam with 0.450" lift or less. More lift than that with stock L31 heads can result in the bottom of the valve spring retainers crashing into the valve guide seals. Of course, there are springs and retainers to cure the problem so you can use more cam lift if you want to spend a little time and money on the heads. You want to know the exact static compression ratio of the motor before you start changing cams.
Wow! All I know is it was a stock engine with no changes. It was a 1/2 ton stepside truck. I still have the truck. I was able to get a complete 350 FI GM engine/ plug and play for the replacement. I do also have two long block LT1's, 94 and 96 year w/o FI if I need a fall back due to the possiability the Vortec is bad. It was over heated causing the replacement.
the 350 vortec is the engine we recommend for the local sportsman racers that are limited to iron production heads and such----very good head, roller lifters and SDPD has manifolds as do Edelbrock---
Vortec injection is the sucky-looking one with the spider tubes underneath the manifold.....history of leaking (eventually). With
that injection, you are pretty much stuck with the factory horsepower and torque.....you might gain a tad with the headers but the rest of the system is pretty much unchangeable (a cam might help or it might screw things up). There are a few folks who tweak these computers. I am a real fuel injection fan but for a hot rod, I would recommend going to a 2116 Edelbrock manifold with a holley carb.....and you have to buy a distributor since the vortec engine didnt have a "real" distributor....the thing that looks like a distributor is a rotor for the plug wires and a pickup. This way, you can trash the computer OR add a better injection system if you dont like carbs.
If changing to a carb, use a dual-plane, high-rise intake manifold such as the Edelbrock Performer RPM Vortec or the equivalent Weiand Stealth intake. You'll make more power and torque throughout the rpm range with this manifold than you will with a low-rise unit. The RPM was mis-named. It should have been called the Street Max. Think of it as a Z28 high-rise. This is my opinion only, but it is shared by others and backed up by dozens of DynoSim pulls.