As we all know we want our cars to go faster. We want "More Power". One of the necessary methods to gain significant power is to improve the breathing of the heads. I think we can also agree that with increasing mods the heads will become a limiting factor.

Now with my car (LS1) the 241 heads are considered to flow well when it comes to OEM heads. However, there are the 243 heads (LS6 ZO6 engine) that will bolt right on to the LS1 long block. It will flow better, but how much? The LS6 engine was rated 55 hp (405 - 350) more than the LS1. Of course this is not due entirely to the heads. An upgraded intake (which I have) and cam contributed also. One course of action would be to get a set of used set of 243 heads and bolt them on to the LS1 engine. The cost would be price of the heads ($500 approx.) and cost of installation (I would need a shop to do it). Would the increased performance be worth the cost?

Then there is the idea of purchasing some aftermarket ported and polished 243 heads. This would provide more flow (and HP). But the cost of the heads would more than double. Then they need to be installed. Of course they would flow more and provide more power. However, I hear that the machining can weaken the head structure with catastrophic results. :shock: The question again is the increase that much better than the LS1 heads (which flow pretty good) to justify the cost.

Then of course there are non-OEM aftermarket heads. I like the AFR 205 mongoose heads. They are suppose to be the best heads for a stock CI LS1. I like the CARB EO number also. It's one less thing for the SMOG man to snag me on. But as everyone probably knows, they might as well be made of gold for the price. They have one of the best flow rates of any aftermarket head. Provide great throttle response with lots of increased area under the torque curve. So great improvement with a steep price tag.

Can you get significant increase in performance over the LS1's 241 heads with an upgrade. If you are going to make the upgrade, is it worth the extra money to go for the better option?

 

First off I think the questions you are asking have to be decided by you. It is subjective thing. What I find worth doing really has no bears on your choice.

With that said, I would personally opt to save my pennies until I could spring for the AFR heads. Keep in mind that going this route has its risks. Say for example you spring for the AFR heads, you put your money down to have them installed, and the shop gives you a call to inform you that they found a crack in the block by the bore. Not that this is likely to happen, but doing any major engine change may uncover other things that can cause you to end up spending way more money then you may have planned for, which brings you back to your question, is it worth it.

Some folks might opt to save their money and buy a replacement engine, maybe a new crate LS3, LS7 etc.. This would be the direction I would most likely choose. Just my 2¢!

 

Thanks for the reply.

Lets just assume that the total cost is not the issue. The issue is the return on investment.

I don't know it track or weekly trips to the drag strip are in my future. I mainly engage is spirited drives through the mountains. Conditions are too variable for 5 to 10 horses to make a big difference.

What is the return on investment. If I am only going to a few RWHP over the previous option, but spend twice as much, the $/HP becomes prohibative. However, I understand that peak dyno numbers are not the whole story. The more efficient flow from better machining or engineering provides better throttle response and low RPM performance. Is the higher price of an aftermarket head justified?

 

I'm not fully understanding your post. If you are assuming that total cost isn't the issue, and if your intent is to increase throttle response I personally would be looking at one of the many aftermarket forced induction systems. With a supercharger you don't have to worry about the head flow numbers, just cram the air down them. Dollar for dollar, most likely the largest “throttle response” improvement you can get with the least amount of engine teardown.

Whatever you decide don't expect any financial return for the money you putout on engine changes. There is no return on this expense, it really isn't an investment.

 

AFR 205 heads with a 224/228 581/588 112+4 cam

 

I guess what I am trying to say is. I would be willing to spend the money on the aftermarket heads if the performance increase was substancial enough. I don't drag race, or street race so a half a length lead over this other guy isn't what I'm looking for.

 

This is what I'm considering if the increase in flow and performance is a full step ahead of the other. But that cam may be a little too radical for California's smog sniffers.

Thanks I was hoping you would chime in.

 

That is Tony Ms cam

He can also do a 224/228 581/588 on a 114 to pass CA smog sniffers

teh AFRs are the ONLY head IIRC to have a CARB number

 

Have you considered a gear change?

 

If it were me not racing it or otherwise I would leave it stock maybe a cai and a catback system, but otherwise you could be opening a very big can of worms and alot of headaches.

 

I expected the last sentence to be "ask me how I know "

I don't track or drag strip. But I do like to drive with spirit. What does a guy with a coupe want? Answer; an LS6. What does a guy with a C5 Z06 want? A C6 or a C6 Z06. What does a.....

I have considered the convienence of leaving it stock. I know some pretty smart people who live by that montra. If you want to go faster and GM offers it (and they most certainly do) then buy it off the show room floor. The beauty of doing this research is it's a least a year down the line. By then I will have settled down and given H/C some more critical consideration.

BTW, has anyone considered the latest Edelbrock heads. According to their website they also have a CARB EO #.

 

After I bent valves in both heads I had a set of 243 heads put on my car and I really cant tell the difference in power from the old heads. I didn't have the car tuned so maybe that would give me some more power but i cant see that making much of a difference.I would do a cam only package before I would change the heads.

 

tuning makes a HUGE DIFFERENCE between 241 and 243 heads. Then with aftermarket PP 243 heads AND CAM there is a lot on the table to be used

 

If money's no object-drop a 427 in. This whole conversation seems silly anyway. This subject has been beaten to death 1000's of times do a search. Easiest thing to do is a S/C and a tune-never even have to open the motor and you'll gain more HP than heads and a cam ever will and you can easily go back to stock if you want too.

 

I think you are barking up the wrong tree anyway.What you are looking for is throttle response and torque.Higher flowing heads help most in the upper rpm ranges.What you should consider is a gear change!

 

that is where the AFR205s with the 224/228 cam shine. Immediate throttle response. In many cases quicker off the line or out of corners or roll racing starts then bigger cube motors too.

may not have the top end, but that is OK.

I run a polished not really ported 243 heads with a 224/224 581/581 112 cam. I have immediate throttle response. my friends with LS7s hate following me though corners on road courses as they just can not keep up. On long straights over 125 mph I am toasted, but I can catch them in the next set of corners.

 

Are any of the super chargers CARB certified? For just fun, I'd be looking at FI. I have no experience with it, so can't say what potential hassles there are with FI.

A head only change of just a ported 243 was one of the best mods I did, it gave a good bump in power. More than the LT headers I put on. Adding a cam latter has proved to be more of a headache, as I haven't found any local tuners that can tune it. I had a mail order tune for the heads and LT headers, but I think once you add in a cam you definitely need a dyno tune. Was heads a good investment? Not bad, they will work with a good number of future mods. And as you may not go radical the chances of you needing a higher flowing head are minimal. I wish I had AFRs as I now have a cam and go to the rack, but for half the cost a ported 243 is pretty attractive.

Not sure if heads and cam route are the best for you, I don't know what headers and exhaust you can use for emissions and without that piece you don't get as much of a gain. But, if there is a FI available that can make good power without having to do much more supporting mods.

 

Bang for the buck,lower gears would give him what he wants.

 

Based on your question, it appears you don't plan to change out your stock cam. If that's the case, I would save your money and leave your heads alone unless you can get a set of used LS6 heads cheap. Personally, I don't think you'll realize a significant gain with changing out the LS1 heads alone while keeping the stock cam. Now if you plan to move up to a larger cam - then there are plenty of great options.

 

If I change the heads I will change the cam too. However, I want to stay within legal smog quals. So I will have to stick with a smaller cam . I believe the main culprit is the LSA which has to be over 114 deg. From the comments I have read I believe this will give it better street manners and lower rpm torque. But this will sacrifice peak power, oh well.

To an earlier post. When I said cost wasn't an issue, I was referring to the increase cost of premium aftermarket heads, provided the gains were significant. A supercharger is not in the budget for some time if at all.