i just bought a second chevy silverado 2500 4x4 this is going to be my tow truck for towing my iroc out to the salt flats and out the drag strip at vegas either of wich is a 300+ mile trip one way

my first silverado is also a 2500 but has had the engine swaped for a l98 with tpi on it

the one i just bought is a 92 bone stock 350 tpi i love the truck tons of power down low cruises at 80mph on the highway no problem nv 4500 or 3500 trans always get them mixed up

anyways my only gripe with the truck is above 3,200 rpms power falls off rather rapidly

im not looking to make the truck fast, i live in the mountians for the most part so alot of my towing will be up and down some long steep grades

first things first im 6,500 ft above sealevel so im already down on power and thinking that is the cause for the early power drop off

what im wanting to do is give up a lil low end/off idle power to get some back in the upper midrange,

i was thinking a slightly larger cam , headers dual ex system , possibly the tbi swap from the 454bb , and i know some of u guys swap the manifolds to a carb manifold and use a carb to tbi adapter


i know alot of u guys are like i am with the v6 engines and know everything there is to know about them and are very good at getting everything u can out of them , so im looking for some suggestions , please rember this is something i use to tow an 18ft camping trailer , and a race car with so mods have to not hurt the towing ability

the only mechanical issue witht he truck atm is when ever i step on the clutch and goto change gears the rpms stay at about 1,800-2,200 if i leave the truck in nuetral eventually they will drop but it takes about 20 seconds

is this the ecm doing this? or do i a bad iac or something

think idles just fine when its warm though its only when i change gears

 

FIRST thing you do is make the engine run like it's supposed to. It is a major mistake to "modify" when you should "repair". Given that this is a new-to-you vehicle, you'll want to assure that any maintenance items are "caught up" since the previous owner probably wasn't willing to spend any money on the vehicle.

I suggest removing and inspecting ALL the typical "tune-up" parts. I don't suggest throwing away spark plugs that still have service life left in them; but you'll want to replace anything that's actually beyond--or near--the end of it's service life.
Plugs (inspect for wear and oil consumption)
Plug wires including coil wire
Distributor cap
Distributor rotor
Coil output test using a spark-tester. (About $12 from eBay or auto parts store there's a half-dozen "brands" and several styles of tool. This is the least-expensive version of the kind I use: http://www.ebay.com/itm/380582995192...84.m1423.l2649 )

Inspect the pickup coil/reluctor on the distributor shaft (Common problem with small-cap HEI distributors.)
Clean TBI/throttle plates/IAC passage
Assure IAC works
Verify PCV valve works properly
Assure AIR system switches from upstream to downstream
Assure temp door, ducting, and control system on air cleaner housing works properly
Connect REAL scan tool, check for codes, check fuel trim, check O2 crosscounts, verify no unusual readings in the data stream. This also verifies spark advance and assures knock-sensor works, but isn't active when it shouldn't be.
Replace O2 sensor if there's any question about it's performance. (I learned this the hard way!)
Cranking compression test
Cylinder power balance test
Inspect all filters, Replace as needed. Includes PCV filter, charcoal canister filter, fuel filter, air filter, oil filter if changing oil, etc.
Garden hose and/or compressed air to A/C condenser and radiator fins, remove bugs and debris so that engine doesn't overheat when it resumes making appropriate horsepower.
Verify fan clutch works properly.
Check brakes for excessive drag
Verify appropriate suspension/steering alignment by inspecting tires for excessive/improper wear. Verify tire pressure, too.
Check for plugged catalytic converter, replace if plugged or non-functional.

There's other stuff that should be inspected--brake/suspension/steering, primarily--on any new-to-you vehicle, but this is about all I can think of offhand that could affect power 'n' performance.