et gain's with heads ....
Traction has never been a problem. Iv built and raced many cars, I understand every aspect of it I just failed to have ever seen a ported head car go faster. Even on a light weight full out race car the difference between the cam only vs h/c is vary little
Pass that **** that you're smoking over here bro.
I know a guy who had tube chassis drag cars then a couple classes of dirt track cars and is a shift lead at a diesel repair shop and one time he told me that the gen 1 350 based engine block 383 in his dirt track car got the extra displacement from the 6.0" rods not from the crank. Point being people can spend decades in a hobby or hell job and still be completely clueless.
Maybe with a 4.8l on boost with a good head like a 243 it doesn't make a big difference, or maybe a stock LS1 intake is choking the heads or something, but take a NA application and the rest of the world's experience is different than your's.
Maybe with a 4.8l on boost with a good head like a 243 it doesn't make a big difference, or maybe a stock LS1 intake is choking the heads or something, but take a NA application and the rest of the world's experience is different than your's.
Just for reference my buddy recently did some really nice heads to his LS2 and gained 5 mph just from that alone. I'm not sure how you could not see a difference with a decent set of heads
I know a guy who had tube chassis drag cars then a couple classes of dirt track cars and is a shift lead at a diesel repair shop and one time he told me that the gen 1 350 based engine block 383 in his dirt track car got the extra displacement from the 6.0" rods not from the crank. Point being people can spend decades in a hobby or hell job and still be completely clueless.
Maybe with a 4.8l on boost with a good head like a 243 it doesn't make a big difference, or maybe a stock LS1 intake is choking the heads or something, but take a NA application and the rest of the world's experience is different than your's.
Maybe with a 4.8l on boost with a good head like a 243 it doesn't make a big difference, or maybe a stock LS1 intake is choking the heads or something, but take a NA application and the rest of the world's experience is different than your's.
As far as the op's comment, if you have built multiple cars but never seen a set of heads pick up at the track then you're just lost plain and simple. Or have never had a working timer at the track. I really dont know what else to say lol
Iv done Afr 215s, PRC 215s, PRC 243s , gmpp 243s, tea 2.5s, ls6, hand ported ect I'm sure I'm missing some. All had 230 to 240 cams in them. You guys completey miss my question, without changing the chamber will porting the runner make you faster? If the answer is yes then prove it. That's all I'm asking. I can make up idea's and pass on what iv seen on the internet too, I just wana see if results
Iv done Afr 215s, PRC 215s, PRC 243s , gmpp 243s, tea 2.5s, ls6, hand ported ect I'm sure I'm missing some. All had 230 to 240 cams in them. You guys completey miss my question, without changing the chamber will porting the runner make you faster? If the answer is yes then prove it. That's all I'm asking. I can make up idea's and pass on what iv seen on the internet too, I just wana see if results
I'm looking for some real world et gain's (before and after) with cylinder head's on an ls1. Iv seen dyno numbers to no end so I'm not looking for that, iv found vary little feed back from people who have done it. I would assume if there positive gain's I'd hear more about it. Iv done many cam and h/c combo's for other people in the past but never one then the other, seems the h/c combo's don't do any better then cam only. I know there's 15-20 HP and 20-30 lb torque to be had with a ls6 head swap but is 1k dollar port job worth it? Let's say PRC or AI ported head or even aftermarket for that matter I'd like to hear some honest feedback.
I know there's a lot of variables but I'd like to hear your combo and what you picked up. Thanks
I know there's a lot of variables but I'd like to hear your combo and what you picked up. Thanks
I have, not trying to make an argument here I'm just stating what iv seen. I understand every combo will be different as well, I'm just curious on your average fbody if you swap out ported heads will you see it on the track, I did a car just like mine nearly the same cam and all only difference was CNC and milled 243 heads and he had a ss4k converter vs my 3400 and he can't beat mine mph or et. All I get is speculation and dyno numbers that's why I'm asking if anyone has done a before and to compare et.
I completly agree with you guys, but the head's work so well stock I just dont think there's that much left to gain, I'm basically asking to be proved wrong but i like to have hard proff, real et gains not just more HP on a dyno. Every company I call about head's go's off on dyno numbers and that's all they have. More peak HP don't mean you will go faster. Bigger ci engine or with a cam/intake setup to pull to 7500+ you will clearly see a gain with ported runners. Like said above a 243 head cleaned up a little does a lot. Air speed is just as important and cfm.
Thunder already showed what happened to his injectors. More air=more fuel= more hp= better track times. The reason no one has head only swap numbers is because 99% of people do a cam with heads so its H/C gains. The main reason companies quote numbers is because dynos take variables out of the equation.
You're running at a track where cars weigh different, have different gearing, maybe theres a headwind etc. All those things can skew mph gains. Instead they can quote dynos around the country that all report between 30-40hp. Those factors still come into play but not nearly like they would at a track. If one dyno says it gains 30hp from a certain head then it might be wrong however if there are hundreds of dynos around the country reporting 30-40hp, then my bet is that it ACTUALLY gains that much.
I agree that poor track results are going to be plentiful because everyone wants to add a **** ton more power but not buy a proper tire or suspension to use what they already have.
Unless you find someone who knows what they're doing and keeps a lot of slips noting the DA it's going to be difficult to gauge results.
I've also seen cars with "ported" heads locally go waaaay slower because someone went hog wild. Sure, they flow "over 330cfm" but the hack job porting killed the velocity to do it and the car goes slower because they have a poor overall setup. A good port job can get around that 300-310cfm mark but retain enough velocity to make power.
It's not much different than a small cam car running faster times than a big cam car because the guy with the huge cam still has 2.73 gears, a 2800 stall, and a 28" tire in a full weight car but chose a mod meant for a max effort drag car.
Unless you find someone who knows what they're doing and keeps a lot of slips noting the DA it's going to be difficult to gauge results.
I've also seen cars with "ported" heads locally go waaaay slower because someone went hog wild. Sure, they flow "over 330cfm" but the hack job porting killed the velocity to do it and the car goes slower because they have a poor overall setup. A good port job can get around that 300-310cfm mark but retain enough velocity to make power.
It's not much different than a small cam car running faster times than a big cam car because the guy with the huge cam still has 2.73 gears, a 2800 stall, and a 28" tire in a full weight car but chose a mod meant for a max effort drag car.
There's some good comments in here! But I would also like to see some real world gains from runner porting only, ($800-$1000) most people will buy heads that increase their compression ratio as well, have a better design combustion chamber, and better valves. So the real question is, how much actual increase in ET/MPH is there in runner porting by itself?
Heres my theory behind it, if I build a cam only setup im going to setup my cam for max effort to work in the rpm range of my intake and header then setup the converter to work with it, if I do a h/c setup I'm going to do the same thing. I did a 233/236 598 lift 108 +3 in mine. There's more left there yet if went all out, something closer to like a trex cam. Now you get a set Afr 215s have Afr set you a cam (I'm sure they did lot's of testing to see what there heads like) and you end up with something in the mid lower 230s on a 113-114 LSA to work in the same rpm range. Why is this? Because the head is more efficient and needs less duration and valve over lap to fill the cylinder. End result... Almost no more power cause you had to change the cam. You guys are right, that's why everyone always changes the cam with a head swap. But what I'm getting at is if you setup a cam correct (and the rest of the car) that you can go nearly as fast on a stock set of heads.
But what I'm getting at is if you setup a cam correct (and the rest of the car) that you can go nearly as fast on a stock set of heads.
Here's a perfect example of how a well setup engine can make killer power with what most would call a mild setup. Do you think a cam only 346 will make 490rwhp and be just as fast as this car?
https://ls1tech.com/forums/generatio...-490-rwhp.html'
I mean sure, you can put a big enough cam in an engine and make as much power as an engine with a smaller cam and aftermarket heads. But the latter will drive much better and be more efficient. Plus you can then put a much bigger cam in that setup and blow away the first one.
Last edited by redtan; Dec 10, 2014 at 02:42 PM.
Yes but you would have to turn it really high then, 11.6-1 cr 6 speed c5 would see 450-460 on stock heads no problem. Drivability I know will be better with better heads and a smaller cam but im wondering about 1/4 miles times only.
However I will rest my case, I was just looking to see if anyone had some good back to back results on cylinder head swaps. Iv been doing lot's of research and have found some nice et results from advanced inductions that I liked. I didn't want to waist my money like I had seen so many people do, if I can actually pick up what iv seen some of these cars claim I'd be happy.
The cam is like a pump trying to suck up water where the heads are the pipe. I the cam aka pump wants more air than the heads can provide, and most all cams want more than stock head air then there will be a restriction. Bigger heads is like getting a bigger pipe ie less restriction.
Take a car with a set of cleaned up or hell wen stock 243s and a 230 ish can and put it up against a car with an ms4 and go from a dig. The ms4 car will get destroyed. Why? Because it makes no torque down low and probably isn't better up top at all thanks to the 243s on the other car. Head not only help out up top where they REALLY serve their purpose is generating mid range tq and power
Guy's I understand all that, like iv stated iv built plenty of engines and know every aspect of how they work, on paper heads gain a lot, I'm just stating what iv seen in real world. I do everything by feel thats how iv always built everything and have always been as fast or faster then everyone else. A wheel dyno is completely worthless to me, a engine dyno can be of some help. I'm not ruling out that heads can help if done right (why do you think I made this thread) but I just havent seen it yet. Instead it's just turned into a "let's call him a dumb *** cause can't build an engine" thread. If you can show me a well built cam car with solid track gains when swaping heads then perfect I'll pick up a set. Am I beating h/c cars because I setup my car better?
A large portion of the cars do heads and cam to gain power/ET but keep driving manners that would be lost with a large cam only car.
I would definitely rather have a head/cam car making 440rwhp than a cam only car making 440rwhp. Because I can pretty much guarantee you the head/cam car will drive better and be more fun off the track due to under the curve power.
You definitely have valid points. But my experience differs. If I weren't switching short blocks to a ls2 soon I could provide even more once more porting is done on my heads...but the shortblock change will add compression and cubic inches so it won't be apples to apples.
I would definitely rather have a head/cam car making 440rwhp than a cam only car making 440rwhp. Because I can pretty much guarantee you the head/cam car will drive better and be more fun off the track due to under the curve power.
You definitely have valid points. But my experience differs. If I weren't switching short blocks to a ls2 soon I could provide even more once more porting is done on my heads...but the shortblock change will add compression and cubic inches so it won't be apples to apples.
I'd definitely agree with you on that, most the h/c car's iv been around tend to drive better, some nearly like stock. Mines vary choppy below 1500 rpm and lost some part throttle power, but it gets after it once you go wot. I bet there's 10hp 15tq just from going from a 112 LSA to a 108, but it will cost you some drivability.
