I do my own head work. It's not real difficult to do and I don't get too crazy mainly just port matching the intake and header along with some cleaning up of the casting for better flow. I am having the head decked and pressure tested which will be about $50. The machining for larger than stock 22r valves will be about $80. Depending on what you do you can make an very nice torque engine or a high rpm screamer. The 20r head flows oh so much better than the 22r version in the upper rpm range and generally bumps the compression up a bit too. In your shoes I'd put a 20r head on an early (pre 85) lower and grab a 4 to 1 header and a weber along with a nice performance cam. I've got a comp 252 in the truck now and it has great power till about 5k then it falls flat on it's face. It'd work sweet in your engine with a smaller carb though. $40 and it's yours.
Ok You struck my Intrest. Here is the always asked question, What if I do build the 22R Block and 20R head and install a webber and header where is my Gas millage going to go? The whole pourpose of having this truck (Besides being one of a kind rare) is Fule Millage. I mean your an offroader you know I have nothing that gets less than 18 mpg $40 bucks and whats mine? Ok I've been giving this a bunch of thought. a friend of mine tells me I can find a 4.3L V6 that would give me more power and give me MPG of 25 or better.. My Question is can I build the Toy 4 Banger and still maintain the 25mpg? So when you port match what bits do you use and do you use a dremel or a drill?
I drive like an ass and have a large carb and I still get 18mpg in the race truck. The 4.3 swap would get you a lot of power and decent mileage but unless you feel like doing MAJOR work to the engine crossmember for oil pan clearanceand the firewall for bellhousing clearance then open up the trans tunnel for room around the trans it ain't going in. Been there and after some time with a tape measure I sold the 97 blazer drivetrain and scrapped the body. If you want power and mileage stick a 3800 out of a GM car in there. It uses the GM 60* bellhousing that is much smaller than the 90* version the 4.3 uses. If that engine can push a 3500lb sedan down the road and make 30+ mpg I'd say you'd do fine. I'll sell you my current cam for $40 if you want to upgrade. Its too small for me. I use a carbide bit on a high speed air die grinder to work the ports. I finish it off smooth with a stone made for aluminum.
well Ok so let me see if I can remember all this when I get ready to start tearing into it. I have 2 motors to do this Summer as Long as the kid don't come home then I'll have 3, My Toyota, My Diesel, and My Rock crawler Sammy.