Hey guys!!

Quick question. I met a guy yesterday that has a superflow flowbench in his garage, and he does head porting/polishing.

The guy has done some really trick stuff with the old Pontiac heads, and does a lot of import and LT1 heads, but has never done a set of LS1 heads before. He does all of the head work for the members of a local car club here, and I haven't seen any complaints.

I am thinking about picking up a set of LS6 heads and having him work them over, but wanted to know what you guys thought were some of the challenges with porting the LS1/6 heads that would be different from say and LT1 head.

Should I trust the guy to work a new set of heads if he has never touched this particular type of head before? I am not going to do anything like a stage 3 port job, just clean them up, maybe the equivalent of a stage 1.

He gave me a really good price, and he showed me some of the numbers he was getting from a light touch on the LT1 heads, so I am very tempted...

Thanks in advance,

Chuck

 

IMHO I would not let him touch my heads if you want to get max power/flow out of the cylinder head and want to keep torque. If you just want to clean up the LS6 heads, sure, that wouldn't be too hard.
The most common thing to do on older heads was gut the hell out of them to increase flow. The LS1/LS6 heads are very dependant on velocity. Most of the stage 2 heads (LS1/LS6) that you see are ported very little, they basically clean the ports, most of the work is with the short side radius, combustin chamber and bowl.

 

I read an article in GMHTP about head porting by ARE, they said there are things (vanes i think) in the intake runners that most people look at and assume they have to go because they look like they restrict the hell out of flow, but they infact spin the air into the chamber to aid in turbulence in the combustion chamber, taking them out is bad (this is all from memory, but It is somehting like this).. there were some other things that they said were different but that was th oen i remember.

 

I would say, let him take a shot at them, But I will add this much from a comment above, you can loose swirl even without touching the air vein if the bowl bias is not set up correctly, that you won't find in a magazine, it's found on the flowbench. These are very tempermental runners and don't like being pushed and pulled around like we used to on the old 900 series castings. Good luck.

 

I'd let him do it. I have a buddy who is basically the exact same as the guy you are referring to. He has done 100's of LT1 heads, as well as many other SBC heads. He recently did a set of LS1 heads for another friend of his, and the car made 423 rwhp w/ a somewhat small cam. The car trapped 121 mph.

If your guy knows his **** about head porting, then he knows what needs to be done w/ an LS1 head. I don't think anyone would take up the task without first having the knowledge on how to correctly port them. Go for it!

Josh

 

I would definitely not let him touch them. The LS6 heads are fairly different from old SBC/BBC heads. It is very easy in them to screw up flow velocity, hog too much out of the wrong area, etc.

Cylinder head flow is the key to horsepower in NA applications. Period. And it takes time to learn any new set of heads regardless of experience. One of the reasons some shops keep *consistently* turning out cars with more horsepower than others is that they have mastered the head work, which took a lot of trial and error. Why else do you think a place like MTI (or some of the other good shops) is backed up for weeks on their head work. Everyone wants it because it is proven.

Put another way, look at the variances in the HP being put down by the larger-cubed LS1 motors, depending upon who did the heads. Anyone can get a big-cubed motor to make low-end torque, but HP is all about head flow.

Having said this, maybe this guy is very good. But you will be taking your chances, especially if he has never touched LS6 heads before.

 

My heads were the first ls1 heads my porter ever did. He put 2.02 1.60 valves and mild porting . The heads and a B1 cam only picked up 86 rwhp or about 100 hp at the flywheel. I was very disappointed. I shoulda spent 2500.00 on the CNC heads..... NOT ..... Id say go for it.

 

Is there really that much difference between say an LS6 head and an LT1 head? Has it changed that much?

Heres the deal, the guy will do them for $300, which is a hell of a lot cheaper than the 2 grand everyone else is charging with a core for a stage 1. I can get the LS6 blanks for $580ish each, so it isn't like I would be out a ton of money if he doesn't get it the first time, and I still get to keep my stock heads..

It isn't like this is completly seat of the pants porting or anything either, he does have a flowbench.

I want to keep the stock heads in a box, not give them up plus a couple of grand to someone so that I can get a set of ported heads.

I think I also forgot to mention that this guy does the headwork for a few of the nascar guys here in NC.(don't know if this makes a diff.)

Guys, I appreciate all of your answers, this will help me make an informed decision.

I know, it sounds like I am being cheap, but I am not trying to build a track monster here, just something that will put me in the 400 rwhp range, and save a few bucks along the way. I haven't seen a lot of horror stories about first time experiences with the LS type heads, so that is why I am even thinking about this in the first place.

Thanks again for your answers,

Chuck

<small>[ March 31, 2002, 12:40 AM: Message edited by: LunaticTA ]</small>

 

Hey I'm about to go through the same thing. A guy here in arkansas Polk performance is known for his s$#t hot port&polish work. So what i did at his sugguestion is find all the info i can. On what to do and what not to do. (like this post ill email him) And then at his suggestion i odered a set of used head cores off a guy on this board for some "testers" for him to practice on the flow bench. Then once he has it down after the first head or two time to make mine FLY!!! Just my .02

 

I'd say to do it. Tell him to just unshroud the valves and clean up the rest.

 

I would let him do it. you will get good results. any real head porter can handle these. look at the home ported attempts people have done. 99% of them have gotten great gains. so a pro can do better.

its not new black magic to any of them...they just have to justify the 2500+ price <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Chuck, let me save you some money here. I'm sure you will appreciate it <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

If you are building up a 346ci setup, skip the expensive LS6 heads. Do this especially if you are not going for the all-out full works port/polish/valve job. The LS6 heads are not showing a whole lot of gain over equally ported LS1 heads on smaller motors. Once you get to the 382ci and higher range, the LS6 heads start to shine at the higher rpm.

Heads are THE most important part of a motor. Remember that and live by it <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

I say get some 5.3 truck heads or just some other LS1 heads and have this guy work on them. You can pick up the cores pretty cheap. If he gets you some great numbers out of those, you might go back to him with some LS6 heads when you do a larger motor. It would be a cheap setup ($400 for cores, $300 for p/p work) and even if it didn't truly kick ***, not much was lost out of pocket.

No, porting and polishing isn't some mysterious witchcraft, but it does take alot of trial/error and experimenting for different heads. Don't spend $1200 on LS6 cores for a 346ci setup.

Tony

 

Thanks guys, and Tony!! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

I have much to more to ponder now.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

LS1tech rules!!

Chuck

 

I agree with the "try the Ls1 heads approach first."

 

i say go for it using the ls1 head or a 5.3 head.

steve frank

 

Can any body reading this topic tell us what intake/exhaust port volumes are for LS6?
TIA <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

 

Lunatic, I say go for it, simply for the fact that I am doing the exact same thing. Im taking a risk, and hes taking his time (its been about 3 months now). I figure if a guy is doing NASCAR stuff then he can make a set of LS1 heads flow good enough for the small cams we can fit in our daily drivers. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Are you guys going to stay with stock valves? If you are, then 5.3L heads have smaller valves than stock 5.7L. I just bought a set of slightly used 5.7L heads to do a home port job on. I know a guy with a flow bench to do some testing. I've also taken notes on some of the pro-ported LS1 heads I've seen. I'll pay a machine shop to cut .030" off the head and have a 3 angle valve job done with the stock valves. We'll see what happens.

Brad

 

The stock valves are not all that great, they don't have the shapes that aftermarket valves have. I've seen noticeable gains (especially on the exhaust side) from just swapping in valves with a different shape.

Stock seats can handle a 2.02" intake and 1.55" exhaust valve. I'd recommend some Ferrea stainless valves.

LS1derfull, sorry I don't have the port volume info myself.

Tony

 

Ditto on what Tony said on the valves... A good set of aftermarket valves (i.e. Ferrea) and valve job will take you a long way...

This isn't really comparing apples to apples I suppose, but I had a set of LS1 heads waaay back that were delivered to me with a shitty valve job. I had the valves re-lapped locally by someone I really trusted, and the car picked up ~5mph and .5 sec just from fixing the problem.