i know on the gen III engines the angle of the intake side of the heads are much different than the earlier models.. meaning a different manifold would be needed.. . but im not sure about them bolting up to the block itself

 

looks like people do the mod, what I read they had mixed comments ranging from increased compression (sounds good to me) to decreased compression requiring "welding the head" which sounds scary to me.

I really want to make plans for a badass price/performance engine to eventually throw into my jimmy, or w/e.

Plus if the heads idea is a go for launch, I can test it on my S.O.'s tahoe. Supposedly better mileage/more hp/tq. How can one say no? I don't yet know how much it would be for a set of heads or the work to make it fit on the tahoe/future engine swap but I will look all of that up in time.

The nice thing about rocking a 4.3 (in the jimmy) is that I have time on my side in regards to an engine swap when the 4.3 dies!

p.s. I found a 1999 4x4 2 door jimmy for 500 bucks with a blown engine. Sight unseen does it sound like a good deal? I really want the dual piston front brakes and the rear disk diff setup. (that in itself pays for the car)

 

You cant put a 5.3L (Gen III) Ls1 type head on a (Gen I) small block chevy.

Yes I know there is an aftermarket block out that will do that now, but this guy isnt asking that question.

 

so the vortec 350 out of the 96-98's is a gen 1 ? I read in a few places about gen 1-2-3 and that gen 1-2 would definitely not support the 5.3 heads but the gen 3 would. I'll have to look into the gen differences to learn more about them.

Thanks.

 

Gen 1 SBC is a ground up design from the 60's, used for more than 30 years. The largest factory displacement was 400ci, but the most common was 350ci. Besides displacement changes there were only two major changes through it's lifespan. The first of which was the changeover to TPI, the second is the changeover to Vortec heads.

Gen 2 is called the LT series, debuted in the corvette in 89 or 90, but was never put in a truck from the factory, just the Corvette, Camaro and B-bodies(Impala SS and such) and is a decent design, though short lived for a reason, the total performance and cooling improvements were pretty minimal. It used reversed cooling and a new bolt pattern for the heads as well as a new TPI short-ram intake manifold. There was also a special edition called the LT5 that was a dual over head cam version and made some damn good power for the time. All three versions made were 5.7L.

The gen 3 is the LS series, debuted in the 1997 corvette as the LS1 in the same 5.7L displacement as the previous generations but in a different bore and stroke. Subsequent versions have taken displacement up to 6.0 and 6.2 versions using essentially the same block. A special edition engine based on the aluminum C5R block for the C6 Z06 that displaces a 7.0L. There is even a pair of factory superchaged 6.2L versions available now.

As far as I know there is only one block that will essentially bolt Gen 3 heads to a gen 1 block and the performance potential isn't exactly worthwhile, there are some great Gen1 heads out there.

If you want inexpensive Gen1 aluminum heads you should look for L98 Corvette heads, they are relatively cheap, but honestly if they're not in great shape, you may as well invest in some GMPP ZZ4 heads or Edelbrock Performer RPM heads.

 

If you want inexpensive Gen1 aluminum heads you should look for L98 Corvette heads, they are relatively cheap, but honestly if they're not in great shape, you may as well invest in some GMPP ZZ4 heads

Both are the same, #113 heads.

 

Thanks for the headsup guys. Glad to learn something new!

 

I seen the new SBC from world products that accepts LSX heads in person at PRI. What a peice of art that thing is. To the OP, buy one! build it and be the first to put one in an s10

 

ZZ4 Aluminum Cylinder Head Assembly

MSRP
$771.43




Enlarge image [+]
12556463
ZZ4 Aluminum Cylinder Head Assembly
Aluminum performance head used on ZZ4 engines
Completely assembled with 1.94/1.50 valves
163cc intake port
58cc combustion chamber
No heat riser
Angled spark plugs (5/8 hex, 3/4 reach, tapered plugs)
1.48 Valve spring seat diameter
Screw-in studs (3/8 top, 7/16 bottom)
Use head gaskets with stainless steel fire rings
Raised, machined rocker rails
Exhaust ports are raised .100, requires Fel-Pro' gasket #1470
Use rail type rockers P/N 10089648, or kit P/N 12370838 (roller rockers!)
Casting P/N 10088113..

 

Interesting, I'll have to see if I can find the picture of the heads I had a while back, that is definitely the standard L98 combustion chamber. :doh:

 

Here's a (not so great) shot of my ~97 Vortec heads chamber:

But none the less, you can make out the 'heart shaped' portion of the chamber that's not evident in the above picture.

 

Did gm make non vortec 5.7 350's in its trucks/burbans/hahoes during 1996-1998?

 

96-98 no, 95 and earlier yes