Hey everyone. I was just thinking about this engine and what anyone thought of it performance-wise. I'm contemplating an L31 V8 for my S-10 Blazer(that's another topic...) that would leave me with one sitting around. I know Hot Rod built one a few years ago that was rather mild(except for the head porting) that made 300 horses at 5,500 and 316 ft-lbs at 4,400. Here's a link to the build-up article:

http://www.hotrod.com/techarticles/engine/113_0208_chevy_43l_262ci_v6_engine_build

They bored it .060" over which would actually make the displacement 270ci or 4.42l. With the forged pistons, studded mains, and powered rods, it should be plenty capable of holding up to boost or squeeze, if you could just open up the intake. As you can see in the article, the roller cam was only 224/224 duration and .525" total lift and a 110 LDA. With 1.6 rockers it becomes .560", but thats still a tiny cam. The heads, even after very aggressive porting, still only flow 208/190cfm. And it can only rev to 6,000 with this combination(I've personally never seen the high side of 5,500 in my blazer).

I know that Comp and other manufactrers can custom grind cams so thats not a problem, but what would be a good profile? Also, how could I get more flow out of those heads? I'm not sure if theres anything on the market to replace them, but that would be nice. In the Hot Rod article, they used a 650cfm carb, but is there any type of fuel injection system that would work good? Or am I stuck with a carb for the peak horse? Not that I mind, as this engine would probably be put in something light for drag racing. Vega anybody? And on the FI front, should I go supercharger, turbo, or nitrous? As much as I hate N2O, I might just go with it because of its on/off nature to keep the car streetable. Anyway, I'm rambling now, so its off to bed for me. Thanks for any and all help.

Jon

Engines aren't my area of expertise but I do know there's a few people that have made some decent horsepower under boost (turbo seems to be the way to go), so it's doable.

the vortec 4.3 is a vortec 350 witht he front two cylinders cut off. i know many 300+hp ones, be it spray or some form of boost. ive got a friend whos running 350rwhp on a stock 4.3 2002 2 door blazer, he's runnin high 7's in the 1/8, 130k miles, and the bitch still runs strong.
its a great motor, and i would personally cam with minor head work your motor. leave the internals alone. e-fans, and go with a 76mm garrett ball bearing turbo mounted where the two exhaust manifolds meet under the passengers seat area. get a decent sized intercooler, tune with a decent a/f with a nice wideband contorller, and tun about 12psi, and youll be sitting at at least 350rwhp.
or you could just spray it. it can handle up to an easy 150 shot.

oh, check out performancetrucks.net
they've got a few built 4.3;s.
02vortech is my buddy with the badass blazer