Thread: v6 chevy

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This is a little different, I am buildind a tbucket with a 4.3 chevy v6 this is just a350 with 2 less pistons so it should qualify as a sbc. I took all the computer junk off put on an Edelbrock performer intake and a 500cfm edelbrock carb and headman long tube exhaust,and a streetsports hei dizzy. The teck at summit racing said maybe 215 hp. Any ideas without getting to far out what might add a little more zip.

What year 4.3?
The "W" motor from the factory was rated 210hp net with a MFI set up and stock exhaust.
Cams, rods, cranks, and pistons were differnt from the "Z" motor and had the balance shaft because of the lightening of the rotating assembly.
The "W" had a better cam in it as well which helped achieve the 210 mark where the older 4.3's were only rated at 155 and 170hp net.

Hey Francis – Great idea to go a bit “non-traditional” with your build. The 1985 and newer Chevy 4.3L; (262ci) V-6 is as you have suggested, a small-block V8 without the number 3 and 6 cylinders. There are a zillion of them out there left over from S-10 pickups and Astro Vans so the stock parts are plentiful. On the “go fast” side of the equation, it sounds like you’ve already tapped into Edelbrock for carburetor and manifold. Good call on the Headmans as well.

You may also know that the bores are 4.40” centers and the deck height is 9.025” (sound familiar?). In 1985, the 4.3L went to the same bore and stroke as a 350 V-8 (4.0” x 3.48”). The, oil pump, main and cam bearings, pistons, all of the valve train parts, and timing cover from a SBC will fit perfectly.

350 pistons are a natural upgrade. Do your homework on compression ratio, quench, gaskets, etc., up front – Stock heads are 68cc and stock C/R is about 8.5 - 8.8:1. With very little work, and a Fel-Pro .040” gasket, 9:1+ is attainable and you’ll be able to still run pump gas with no problems. The rods are 5.7” like the 350, but have a larger journal size (2.250” versus 2.100”) so make sure you plan accordingly if you’re going to swap rods. The stockers are really pretty good and your machine shop can clean them up, resize and shot-peen them (may be some disagreement here, but quite simply, shot-peening rods makes the rods more durable by strengthening the metal and reducing fatigue). The 4.3L is an internally balanced engine and uses the same harmonic damper(s) as a 350.

Comp Cams has a plethora of cam kits for the 4.3 but I’m a bit on the conservative side here not knowing what your overall build will look like. Summit Part number K18-124-4 has the following: cam, lifters, valve train, (hydraulic flat tappets, springs, seals, and clips – no pushrods). The advertised Duration 268/268, Lift .454/.454. Price is about 300 bucks. Note that the springs in the kit are 1.43” diameter and the heads need to be machined to accept them. The .454 lift may be a bit tight as well and I’d have the machinist relieve that and install 3/8” screw-in studs (since we’re already there!).

Summit carries quite a few 4.3 parts as do the guys at Six Banger Performance (http://www.sixbangerparts.com/chevv6performanceparts)

GM Performance parts catalog shows a lot of parts to ranging from aluminum blocks and heads, to special intake manifolds – but know going in that GM is really proud of their parts.

Brodix makes aluminum heads that bolt on and are designed for the Edelbrock intake manifold http://www.brodix.com/heads/v6.html.

Little work and this thing will sound great, push real close to 300HP, and in a nice light bucket run like grease through a hot tin horn!

Have Fun!
Glenn

Later models had self aligning rockers and the screw in studs to go with.
Francis, help us out with the vintage 4.3. You may have a great piece that with the stuff Glenn mentioned, it'll be a torque monster. Or you may have the big cam already. Depends on which 4.3 you already have.
Although I'm not a huge big user of Crane stuff, they do have a couple of cams that idle great and will wake that thing up.

This engine is out of a 1991 s10 it is not a vortec the manuel for that year says 160 hp stock but that is with the computor and rev limitor and tbi.I have not been inside of this engine it has 56000 miles and is reaiy in good shape. I didn't know anyone made after market heads fir it that is VERY interesting. I like a lite engine keep the overall weight down and make a real sleeper of it

we used the 350 chevy pistons in them your block should be a roller cam engine .they made a marine dual plane 4 barrel iron intake for them as well as the roller cam 224/224 450/460lc 112 . the ZZ4 or LT1 vavle springs are drop ins and there others as well PBM springs 3200 ,it will haul with the cam and intake swap out the dish pistons and use flat tops .some bowl work in the heads and you will have a killer i like the 4.3 better then the old 350s alot of the boats i work on the 4.3 ran great .mercruiser built a 1/2 of a 460 ford 4 banger 470-485-488 it was 224 cid allways wanted to build small dirt tracker with one of them in it

Thanks a lot guys I had no idea there was that much could be done with that motor. A good friend of mine owns a automotive machine shop and does a lot of high performance work I will get with him and for some parts.