92 Chevy k2500 5.7 Power Options

K2500Polo · December 1, 2021

Hey everyone, so I'm pretty new to the chevy 350's. I have the 350 small block tbi with an NV3500 transmission. I'm looking to get more power and see what peoples builds are because the 350 is gutless with this transmission. Thank you all in advance!

CamGTP · December 1, 2021

Nothing out there will control the TBI system so you are limited on options.

Changing the gearing in the best bang for your buck without touching the engine.

Past that you'd need to do aftermarket cylinder heads, larger camshaft, switch to a carb or go with a modern EI intake manifold with a stand alone engine controller to get a lot more power from that engine.

HoosierZ · December 2, 2021

The TBI engines are OBD1 controlled. They are tuned by burning a new PROM chip. At one time, Hypertech, JET and other companies made replacement chips for the TBI trucks. They may still. I had a ‘94 K1500 with the TBI 350. I added a Hypertech Thermo chip with their 160 deg thermostat, shorty headers, Edelbrock TBI cam and lifters, 3/4” throttle body spacer (don’t laugh, they actually work on the TBI engines, just like carburetor spacers), 1/4” injector spacer (allows more airflow between injectors and throttle body bores), adjustable fuel pressure regulator set to 15-16 psi, fuel pump for a ‘97 Vortec 350 (higher pressure capability than the TBI pump. Direct swap, same connections and wiring). I also set up the throttle body and increased the bores by 1/8” and made new butterflies and did some other mild porting and smoothing to increase airflow.

After all of those modifications, I really needed to have a custom chip burned but I never did get one made. I estimated it was probably making around 250 hp, up from the anemic 210 hp from the factory. The ‘96-‘98 Vortec 350 was rated at 255 hp.

dna9656 · December 2, 2021

What about a different torque converter? I have limited knowledge of transmission builds for power, most power upgrades are sought after in the engine with stuff HoozierZ did and I have to ask; do you really want to burn MORE gas at over 3 busks a gallon? I would do things like tuned headers and smoothed out intake passages Like Hoozier did, the spacers, that stuff allows a smoother flow of fuel you're burning now insead of putting considerably more fuel in the cylinders.

Most tranny upgrades use the same gear ratios, they can use steel or forged steel gears (are there such things as forged gears or are all gears forged?) instead of aluminum, as an upgrade, you can add more steels and disks to some transmissions, sometimes there are higher performance shifting solenoids (like using Corvette solenoids in a car tranny.

Search for NV3500 and read the hits, you'll learn a lot just reading the hits. The edition for trucks MAYBE modded for heavy duty as opposed to the models for cars, I donno.

HoosierZ · December 3, 2021

The NV3500 is a 5 speed manual. No torque converter.

Are you sure it’s not an NV4500? The 1/2 ton trucks got the NV3500. The 3/4 and 1 tons got the NV4500. If it’s a 6-lug light-duty 3/4 ton, it may be the NV3500.

Check out Harris Tuning/ TBI chips. Lots of good info under “Recommended 350 TBI mods”.

Edited December 3, 2021 by HoosierZ