i have been looking for a set of aftermarket heads for my 4.3 and cant find any. does anyone make them ? i hear stock heads flow real good so i think i might be better off porting my factory heads. the reason why i want to keep the 4.3 is because everyone does a engine swap ( unless i can fit a LT1/LS1 in there i dont want to do it ) i want to be a little diffrent and stick with the 4.3. i already have a 69 GTO judge and thats my speed toy. i want something that will get better MPG. any suggestions?

 

timetoblaze has a set for sale in the for sale or trade section that are ported, but you already knew this.

No one makes aftermarket heads for the 4.3L v6.

 

i was under that assumption since i couldnt find any online. i just wanted to make sure.

 

Brodix makes aluminum heads for the 4.3.

 

That is good to know. Too bad they will not work on the newer engines. I should have clarified my statement a bit more.

 

You can make your OE 4.3L heads work just as well as Brodix headson a4.3L engine for half the cost but you will need some extras.That is why Brodix never sold many of those heads and why they are so difficult to find today. Stock 4.3L V6 heads flow about as well as stock 305 Chevy V8 heads,140 CFM Int. & 116 CFM Exh. Professional porting and flow testing on stock heads can bring the numbers up to 208 CFM and 190 CFM and would cost $1000, but would only be necessaryon turbocharged and competition engines.

You do not need high cylinder head flow numbers for a 4.3L V6 engine because it at peak powerby 5000 RPM. That is why cam choices for that engine are so limited. A relatively mild cam grind on a Chevrolet 350 V8 is a radical cam grind on a 4.3L V6.

As soon as I can locatesome rebuildable 1991 "768" 4.3L V6 heads,I will do the following:

Perform a3-angle valve job, port matching, no porting and flow testing.
Install:
Valves,2.02" intake, GM-12363753, undercut, stainless steel, chrome stems
Valves,1.50" exhaust, GM-12363756, undercut, stainless steel,chrome stems
Machine the heads and install teflon positivestop valve seals, I & E, Comp Cams #503
K-line phosphor-bronze guide liners, .0015" (I) and .002" (E) strem clearances
Tap the heads for 7/16"-14 threads and install GM-12495497screw-in rocker studs
GM-10134358valve springs, 110# @ 1.700"
GM-14003974 retainers
GM-14011051 pushrod guide plates
GM-10051147 roller cam,222 deg. at .050" lifter rise, .447" valve lift., 114 deg. LCA
Comp Cams roller lifters, 850-12
GM-10456413 distributor gear, .491" shaft dia.
GM-10134309 pushrodsw/guideplates, 350 H.O.
Comp Cams roller rocker arms, #1301-12, 1.52:1 ratio, 3/8" studs
Cloyes double roller timing set, #9-3145(will not fit plastic timing cover)
Timing cover, Dorman #635512, V8,metal, 10-bolt + 2-dowel (or bolt) holes.
3.42:1 or 3.73:1rear gear ratio and complete internally engine balance is required.
B&M Transpak shift kit, #70235
Jet Performance Billet Power Servo 1-2 shift, #700222 (on outside of trans.)
Jet Performance Billet Power Servo 3-4 shift, #700219 (in valve body)
Summitcast aluminum transmission pan, #1008R for 3 qt. increase.
Maintain the stock, single exhaust system.
Thanks forthe help from Kim Barr Racing Engines, Garland, Texas.

Thislittle puppywill appear to be stock and canrun with thebig dogs. Thevacuum operated devices and emission electronics will work normally.

 

A relatively mild cam grind on a Chevrolet 350 V8 is a radical cam grind on a 4.3L V6.


this is true because of the 100+ cubic inch difference between the 2 engines. i can take the cam that's in my Judge (428) and put in a 400 or a 389 and it would be a night and day difference. i was just looking for options on the truck instead of boost. i want to keep it n/a

 

thread from the dead! duntov was banned but i kinda am interested in his mod list here for the 4.3l since that is the boat anchor that i got. would like a little extra oomph in the blazer as sometimes it seems like it can barely get outa its own way. it might be the lift and huge tires though. I Don't care if i blow the motor since I already priced out a 350 swap and that seems pretty easy so I was thinking strap a better/machined head on the v6, k&n filter, larger head studs, and for a little something extra, nitrous!

edit-brodix head is $350 would it be cheaper to have someone machine the stocker?