ok I now have a starting platform for my first engine build, a 350, 4 bolt main from an 83-85 suburban, I have thought about finding some L31 heads but I'm not sure yet, as I have just started brain storming, my goal is to build it to around 350-375HP

It is going to be a naturally aspirated and carbed engine

I want to get an idea of prices for machine work and what to expect and what I should do as opposed to what they'll tell me I should do, what adds the best bang for the buck? plus, how do I pick my cam and other components? im not builing and all out drag car but I would like to take it down the strip every now and then and not get laugh at.

Honestly one of my objectives is to beat my brothers 96 Z28 that supposedly has the SS motor in it with a 6 spd. (mine has a 4speed that has very similar gear ratios)

its just a friendly sibling rivalry

 

The L31 heads are the cheapest heads that will get you to 350-375 HP, forget any other iron Chevy heads.
This is a fairly simple build, just find a machine shop with a solid reputation for honesty.

 

should I be pushing for more HP? where can I find L31 heads? what years and models did they come in I was told 91+ chevy trucks, thats a pretty broad braket.

 

NO! '91 was still the LO5, with the good-for-nothing swirl-port heads. The L31 debuted for '96. You can get them used, but if they need the seats cut, better to not even try. It's virtually impossible to beat the GM valve job, any other combination of angles and widths will hurt not only flow, but also charge motion and other things. Better to just spend the $540 + shipping for a new pair from www.gmpartsdirect.com

 

For what you get, it's hard to beat this package http://www.sdparts.com/product/SD806...RPMAirGap.aspx .

 

how do you know if its a Vortec? there is a guy on the local craigslist parting out a 98 chevy 2500 4x4 with a 350 how can I tell if it has Vortec heads?

 

Ask the seller to provide the casting #'s from each head.

'96-'99 light truck should be Vortec.