I know these heads flow like poop, but here is the plan: unshroud the valves and clean up the combustion chambers, gasket match the ports and extrude hone the heads.

Do I need to cc the combustion chambers; should I and can I put in bigger valves; will enlarging the combustion chamber around the valves drop the compression ratio appreciably; will this effect my ability to pass smog; WILL ANY OR ALL OF THIS DO ANY DAMN GOOD TO GET SOME HORSES OUT OF THIS ENGINE?

These are going on a 3.4 when I do the swap...

 

My heads are ported, small power increase, but I also have a cam and other things. But if you plan for headers, and a cam, i'd port the heads too.

 

You would probably spend less on a 3x00 swap than extrude honing. I wouldn't waste the money on them.

 

You could build a hybrid that makes more power with the money you spend on getting the iron heads ported.

 

I am not going to mess with a hybrid- this is the People's Republic of California: I have to hide from the smog police, that is why I am going with a 3.4 swap with the 3.1 intake in place...

 

You should be able to legally swap in a complete 3X00 motor. As long as all the emissions stuff that goes with it goes too. They don't need to know what pcm you're using and I doubt there would be any question of it.

 

Actually to get a cert to do the swap, it has to be complete engine and PCM from the donor vehicle. Unless you know someone, it's tough to get away with things like that in Cali.

 

I just love how every time on here that someone asks how to get more power out of a stock set up someone suggests doing something completely different and thats how the rest of the thread goes. The OP wants to know what to do with the stock heads, nothing else. Don't give him the hybrid run-around nonsense if he doesn't want to hear it. He already knows what he wants to do, help him with that.

 

The idea is to help people with their ultimate goal. Just because it's the way the think they want to do it doesn't mean people cannot save them a ton of time and money by suggesting they do it a different way.

 

Right, but you see some of us have been doing modifications for years. I can attest that it is MUCH more expensive to modify the iron heads than it is to just bolt on stock ones from another car. I recently did a set of 3800 heads as they have no stock upgrades they can do. It cost the customer $700 for bare heads and I had about 60hours into them, just to get them to flow almost as good as stock 3500 heads do. Now the 3800 heads flow better than the iron 60 degree heads, so is it really economical NOT to swap?

QFT. Again, there's always a better option and giving advice that can save someone time and/or money shouldn't be frowned upon.

 

You'll never find another set of heads on my car other than what the general wanted on them. Some of us want to put the work into a stock setup, and I would do it just to say that I'm not another hybrid junkie. And thats all I have to say.

 

Let me say it again slowly, so everyone understands: I AM NOT BUILDING A HYBRID! I live in California and it is tough enough dealing with smog every two years without having a BAR referee reject my car because they don't think the hybrid is kosher. I can swap in an LS1 that weighs 28lbs more than my iron V6 for less money and hassle than cobbling together some hybrid and trying to make it work. There is always someone bigger, stronger, faster than you; there is always a better, cheaper, faster mod available than the one you are asking about, so let's stop all this johnson measuring and, to quote the character Simon from Braveheart- "Answer the f@#$ing question!"

Do I need to cc the combustion chambers; should I and can I put in bigger valves; will enlarging the combustion chamber around the valves drop the compression ratio appreciably; will this effect my ability to pass smog; WILL ANY OR ALL OF THIS DO ANY DAMN GOOD TO GET SOME HORSES OUT OF THIS ENGINE?

If you can't answer the question, then please refrain from commenting... thanks to those that can assist.

 

OK. I will believe that when I see it.

Anyways, if you want to dump the cash on the iron heads, then fine. As mentioned before I have ported v6 iron heads to flow 38% more than stock and that's leaving the stock valves in. With the 60* iron heads, you aren't going to fit much bigger valves than stock and the expense is not worth the gains.

Being in Cali, I see your point now.

Here's what we do in my shop for the 60* iron heads...
http://www.60inclusive.com/index.php...php&p=tkoheads

Not saying it can't be done, but generally don't want customers to spend money they don't need to. Only trying to help my man.

Oh and here's that car idling with our custom matched "thumper" cam and obd1.5-obdI swap kit in a 3.4 Fierbird that we tuned, can you say "no vac at idle?" lol...



How's that for iron heads?

 

LSx swap = approximately $4000 just for the engine and transmission. You can get them cheaper but beat to hell and back.(thats why the 5.3 is becoming popular) Now that we have the base price, you need the parts to make it all work, another $2000 maybe? If you are doing the work yourself, then thats about what you would spend, if you are paying a shop to do it, then i hope your pockets are deep. And you still need the smog police to go over the car and make sure everything is legit. Not sure about Cali, but here in PA they charge you a nice sum to do so. The numbers i mentioned are very rough estimates based on prices i have seen over time. You can stave off some of the cost by finding a complete donor car to rob everything off of including all the smog stuff. Hybrid = less than half that cost. Not pushing the Hybrid theory just stating facts. And arguing facts is like taking a shower with your socks on. To work over those iron heads, figure on having at least $1000 saved up to make sure you are covered. Might be overkill, might not be but i have seen prices in the $700 range to port those heads. You can't put much bigger valves in those heads than what is already there so again, bigger valves won't help much, if at all because those heads flow so poorly.

 

Hmm, those statistics sound eerily familiar...

Anyway, back on topic.

I've heard that smearing poo all over the ports and cooking them in the oven for an hour helps flow dramatically. I've also heard that beating on iron heads with a hammer like project89 did helps but that's a different subject.

I don't think deshrouding your heads is going to drop compression too much. You shouldn't need to do much to get them deshrouded. Will the smog ****'s poo on you if you put a turbo on it? Because that's the only way you're going to get a decent amount of air though them.

 

They can be made to flow, just not cheap to do right. They have to be ported and tested on a flow bench. When you start making irons flow good, you have done so much work to them, that you can't possibly be close to consistent without a flow bench and some way to measure volume. $700 is on the cheap.

On the shrouding, I saw about a 3% gain from the last set and lost cc's in the chambers, but when you are talking 50+ cc's, 1-2cc is a small percentage compared to the FWD fast burn chambers. One point loss in compression isn't going to be detrimental to overall performance when increased flow is introduced, but then again, now you should make the chambers/ports close in size, and how are you going to do that by eye?

EDIT:

I recently brought a car for before and after dyno sessions. With using less compression, better flowing heads we were able to raise the rev limit. Torque increased from 140-145wtq and from 102whp-134whp while only moving the peak ~1200rpm on an 8.3:1scr 2.5l N/A (don't know why we are testing that ).

 

Thanks for posting that FF. I forgot about the needed flow bench testing. And bl85 is right, about the only way youre going to get good power out of those heads is to turbo it. Even at that youre going to need a tune. All that work and money for about 20HP seems moot(non-turbo ported iron heads only) when you can just drop in a 3.4 with your stock intake and accessories the smog police would be none the wiser and you get about 160 HP out of it which would be more than a 3.1 with $1000 ported iron heads.

 

+1 for the 3.4 swap. Or just a wet 75 shot.


Is the time, money and eventual disappointment worth it to throw a bunch of money into the iron heads?


Perhaps since there was one or two applications where a gen3 engine was used with OBD1 (1993ish Olds was one) you could throw in a stock 3400 with that ecm and harness, tune it and pass emissions better than your gen1 engine ever would.

Several years ago i explored that option for J-Body use, i have the ECM, bin file and code but i need to find a harness. $1FA code looked kinda neat, i bet it would handle a big cam better than older SD code.

 

hehe forgot about the spray :P I don't know how that is tolerated in Cali though. They have the worst emissions laws ever.

 

Now we are getting somewhere- thanks guys. Looks like you are talking me out of doing a ton of work on the heads.
This is just my daily driver that I am wanting to improve, not some weekend warrior. I am just weighing the options, that is all. Ultimately, I will go the LS1 route perhaps, but in the meantime, it will be getting rear discs with a posi etc, so when it comes to putting in the LS1, a lot of the other parts will already be factored in or installed.
The reason I am going 3.4 initially is that I have over 250,000 on the 3.1 and since I can pick up a 3.4 for $250-400, the 3.1/3.4 sway seems a cheap way of improving the car- but if I have the 3.4 down to be freshened up anyway, I thought I would look into improving the heads, since that is the choke point for these engines.
Nitrous is out- it is illegal on the street here and it is a daily driver as I said- reliability is an issue.
I have read tons on the hybrid, but almost everyone doing one seems to be still 'doing one' and explaining to the BAR ref 'that is an LS1 from a 4th gen/corvette' ultimately is easier that answering 'WHAT the hell is that?' when I tell him that is a 3.4/3500 hybrid with a custom blah blah blah...'
Perhaps I will just gasket match the ports, since I have done the intake like that and just go with some headers. Any ideas on what kind of horsepower improvement I will get just doing that with new valves and seats, 1.6 lifters and a mild cam?

 

Gasket matching will only net a small improvement since the heads will not be fully ported. If you change cams be sure it has a CARB number to show the guy at the inspection station because the emissions machine WILL pick up on it by sniffing the exhaust stream. All told you might gain about 15 HP give or take. A better cam works in tandem with higher flowing heads so changing cams will probably not do much unless you get a very mild towing cam or something similar. That might move your torque peak and HP around a bit but thats about it. I have seen too many big cams in cars where the owner thought it sounded badass and it just falls flat on its face because it cant breathe the way the cam was designed to do.You can probably get a set of headers to throw on to make it breathe slightly better. Remember tuning is the key to making it work well. Without a good tune and just throwing parts at it, you won't get what you want except a lighter wallet. The LSx route is a great swap but expensive as hell. Better start saving now as youre going to need about 5 to 6 K unless you can get a wrecked LS1 Z28 or Firebird for a good price to rob everything you need off of but you will probably pay that anyway for it. For what you want to do, just freshen up the 3.4 and put on your stock intake, give it a good tune, and call it a day until you get your LSx swap parts.

 

Thanks 86TT. That is probably the straightest answer on this thread. I think that is the route to take- a freshened up 3.4 as described seems the sanest route(Is the cost of the LSx swap the reason the LT1 seems so popular, by the way? The LT1 has to be a lot heavier than the LS1 though... save that question for another day!).
When you say a good tune- anything special you are talking about, or just the standard tune up at Joe's Garage?

 

Depends on which LT1 you get. If you nab an aluminum headed one, the performance and weight is comparable to an LS1. And yes the cost is one of the main reasons for the LTx swap. By tune, i mean interfacing with the ECM with a laptop and recording data and making changes to the PROM with a good editor such as TunerPro. It is a little more advanced than just throwing a fresh set of plugs,wires,dist cap,rotor etc., but it is not hard to learn and its rather rewarding as well. A tune-up is ALWAYS a good idea though. Your stock ECM will run the 3.4 with no issues as it will adapt for the increased displacement. To unlock hidden horsepower, tuning is the key.