How tight are you going to wind this engine up to???? If you have a "Mexicrate" 1915cc unit, it will have a non counterweighted crankshaft.... This isn't a bad thing until you start pushing the tach needle over 4500 rpm on a "regular" basis....
Find out what you have befor you make any BIG ($$$$) decisions.....
Remember, reliable speed costs money.....How fast can you afford to go????
For the guy who's going to drive it around and rev it up once in a while (remember, we're working with what we have here, are on a budget and don't have the luxury of a new build from scratch), replacing the dual 1 barrels (ICT's) with 40 mm dual 2 barrels (IDF's or HPMX's), porting the stock valve heads, upping the compression a tad, adding ratio rockers (and solid shafts if it doesn't have them already) and maybe upgrading the exhaust isn't going to drastically shorten engine life unless Bobby constantly drives the nuts off it from the moment he starts it to when he shuts it off (and even then it's surprising how long it will go). Yeah, a counterweighted crankshaft would be nice for maximum life, but given the fact that these are fairweather toys and probably won't get driven more than about 5,000 miles a year (tops), it will be 5 or 10 years (or longer) before the damage a stock crank can do will be evident. Would I change the cam and put big valve heads on it so it makes power another thousand rpm (or more) higher with a stock crank? No, as that would be asking for trouble, but for this it will be fine. I'm not saying Leon's point isn't valid, but it's what Bobby has, he's not ready to do a full rebuild and these engines are amazingly resilient. Unless it's bagged already it will take it and be a very fun engine.
Bobby- If it has ICT's, they are almost at their limit. They are 1 barrel carburetors with smaller throttle plates and venturis, and while suitable for the engine in it's present configuration, will need to be replaced for any significant hp increase.
Yes, I know we need to know exactly what's in this engine before really doing anything, but given it's "Super 90" 1915, we can make some basic assumptions- the 2 most important which are it probably has stock dual port heads and a 5,000 or 5500 cam. We can't do anything about the cam without splitting the case, but some porting work, ratio rockers (don't forget the hd aluminum pushrods to keep valve train weight down), more compression and dual 2 barrels will be a nice little extra kick in the pants.