4.3 heads

[jdhogg]

im kinda dense sometimes guys so please humor me.ok i found a set of 96 heads for 250.00.will they fit on my 94 engine without major mods.
hope everyone had a joyful christmas

[Sparky2263]

I coulda' swore we had a how-to on the conversion. Damn!

I think there is a spacer you have to buy for the intake to work, The heads bolt right on and the headers still work, there's just something with the intake.

I'm sure one of the guys that's done it will answer.

[jdhogg]

see sparky,this is what happens when ya get over 35.yer memory shrinks to the size of a bull fieldmouse

[Sparky2263]

***** of it is, my kids take advantage of it........

"....but you said!!!"................."I did?".........

[Maximus]

They will bolt up no problem but the intake is were the problem is.If you have TBI then it can be done with a Edelbrock intake and adapter plate.If it's CPI then it's a little more complicated.There are some machine shops who will do the work to the heads to have them work with your intake.But the intake and exhaust port designs are different and still don't line up right.So in my opinion you loose the over all benefits of the heads because of this.You could get someone to do some heavy port and polish work on CPI heads and go with larger valves to get more air out of them.They still won't flow as much as vortec heads but it will get you close to them.

[rat]

The difference in '96 up and '95 down heads is mostly the intake side. The intake ports are .1" taller. They are simmilar to the lt1 intake runner design.

The intake bolts are also different. There are 4 bolts on each side of the newer intake manifold. They are right in front of and right behind the coolant passages, and point streght up when the heads are on the engine.

The older heads have more intake manifold bolts, and point streght up compared to the intake gasket surface.

[THA_BAD_ONE-0]

but i though it was some head off a vortech to bolt up to my tbi like 92-94 right

[jdhogg]

hell now im lost,i thought the 94 engines were vortec too.wood a good port and flow job do anything for my stock heads?

[Sparky2263]

hell now im lost,i thought the 94 engines were vortec too.wood a good port and flow job do anything for my stock heads?

Yes. The 1.94 intakes are plenty big. Open the exhaust up to 1.6, use neck down valves and port match and clean. No major porting needed and that'll carry you to 300-350 hp. If needed.

[rat]

hell now im lost,i thought the 94 engines were vortec too.wood a good port and flow job do anything for my stock heads?
'96 and up have vortec heads. These vortec heads have the different intake bolt pattern, and different port shape.

'95 and down the good heads were the cpi heads('92-'95). They flowed better than the tbi heads, and are interchangeable with tbi heads. The cpi heads don't flow as well as the '96 up vortec heads though.

This is the only thread i have seen that actualy compares '96 up heads to ported cpi heads in terms of flow. The vortecs flow better than the ported cpi's here. Weather it is worth the extra hassle of getting a different intake manifold to make them work is up to you: http://www.s-seriesforum.com/forum/showthread.php?s=&threadid=31978 you have to register to see it, registration is similar to this site and is free.

[Sparky2263]

Rat, I'm real skeptical of those numbers. Reason being the people and motivations involved. Don't get me wrong, I know the Vortecs flow better.

Just not that much better and the key is the 1.6 exhaust valve.

[Maximus]

I have always found it real funny how a CPI engine makes 195hp and the 96 up engines never made more than that.You would think with the SFI and vortec heads and all the engines could be pushed past a a speed density CPI engine.I don't doubt that vortecs flow real well that is common knowledge.But I'm not sure that the CPI heads don't flow a pretty good amount of air too.Just thoughts I had anyway.

[94s10]

i'm sure that higher horse power rating had alot to do with a better intake manifold design and a superior camshaft, not just the heads

btw i think $250 for a set of stock 96 vortec heads is a rip off. you can get them for 100-150 easily if you look around

[THA_BAD_ONE-0]

so 92-95 heads will bolt right up to my tbi right?

[Sparky2263]

yup

[94s10]

make sure they are L35 heads and not LB4 heads, dont just grab any 92-95 heads. they still used the LB4's in some 92+ trucks. i'll search for some L35 casting numbers you should look for and post up later

[94s10]

10238181, 10077626, 14099064, & 10240209 for 92-93 L35's

10238181 & 10240209 for 94 and 95 L35's.

theres prolly more casting numbers, but thats all i could find for now

[Sparky2263]

Gonna sound dumb coming from me, but what's the difference between the L35's and LB4's? Those are engine designations, not heads.

[94s10]

people call the heads that because thats usually the type of engine they can be found on, i just followed suit

the L35 heads flow a little better and have a combustion chamber that looks more like a vortec chamber as opposed to a LB4 chamber. according to syty guys, the L35 chamber is more resistant to detonation. syty's have LB4 heads stock and alot of guys switch over to L35's

[jdhogg]

i just found some heads off of a 1999 engine for 170.00 a pair.now what adapture plate do i need?

[94s10]

if your talking about an adapter plate to fit your stock intake manifold on the 99 vortec heads, then there isnt one. you have two options, modify your stock manifold to fit on them (which requires welding aluminum and machine work to the manifold and heads, can get expensive) or get a edelbrock 2114 intake manifold and a carb to TBI adapter plate to bolt up your stock throttle body. the first option isnt worth it IMO cause the TBI manifolds are crap. your most likely going to need a custom tune either way, but the 2114 will require the EGR system to be removed, bad if your in an emissions state...

[jdhogg]

nope,orygun aint like california yet.and i went lookin and bought a set of 96 heads today for 125.00.they came off an engine with 23000 miles.i watched em pull em and the car was brand new except for this big dent from the rear bumper to the front seat.edelbrock makes a tbi manifold for the 4.3,or thats what they told me when i called them.but im still thinking about a port polish and bigger valves for my stockers,my neighbor builds race engines and loves good weed.hmmmmmmmmm

[Maximus]

The TBI intake Edelbrock makes isn't for vortec heads only TBI or CPI heads.Like 94 said you either have to mod the intake "crapy option in my opinion" or get the 2114 intake and use a carb to TBI adapter.Holley makes a nice one but there are a few others out there to.

[jdhogg]

hmmmmmmmmmm,i think im gonna talk to my neighbor and see what a set of bigger valves and a port and polish job will do.i want the heads to breath atleast up to 5500