new guy here

I'm the newbie, and I just bought my first BBC yesterday. I need a little help on a few things and a few answers so lets begin
I now own a 1991 Chevy2500, 4x 4, 454 with auto Trans, xtra cab, long bed that I picked up for $1300. It starts effortlessly, drives smoothly, shifts a little hard from first to second, and pulls like it should. I would like to get more power out of this motor and I'm going to add long tube headers, K& N air filter, and Full tune up. What can I expect from a cam , and how big can I go before I need to change out my valve train and what can I also to to improve performance before I do a total rebuild. what does an average build up cost to get about 400-500HP and are there any secrets to getting that on a budget.

Welcome, And at some point Pat Mccarthy (our own big block engine builder guru) will be along with some tips.

I want to do a budget build for towing purposes. maybe a little fun here and there but mostly to tow my boat and motorcycles. all of my previously owned tow vehicles were diesel trucks and I was hellbent on not having a truck payment for a rarely used vehicle. I would like it to sound healthy and perform while retaining the factory fuel injection. I can go carb if needed to because where I am there is no smog. Also it's there a tbi friendly intake manifold that will still clear under the hood?

Welcome. I just finished building my first BBC, a 496. Started out a 85 454 motor from a C3500. It has taken me 6 months but I was in no hurry. Pat answered many of my questions. I have been reading this site for 3 years trying to get all my BBC knowledge.
Your questions should focus on what you want to do first and what you want the final package to be.

First and final package can be all at the same time. I work two Weeks on and one week off. So doing a build can be achieved, I would just rather be able to get where I want to be without spending $4000 to get there. This is not a hot rod or a show truck. Just want to have the bottom end to pull a boat up a launch ramp with out needing a huge stall torque converter and I want a healthy exhaust note and cam.

What gear ratio and tire size you running???
A big healthy sounding cam is going to kill boat ramp torque----------

Stock and stock. Most likely 4.10s and 265x 75xr15. Not looking for seriously healthy, but it would be nice.