Performance Induction's NEW cylinder heads
12-27-2009, 07:03 PM
#61
While pivot location and pushrod location are influences on a rocker design, it seems valve location would be as well. Changing only one with a given rocker can lead to serious problems, like only half of the rocker tip sitting on the valve tip (extreme case). Therein lies my question: if they moved the valve centerlines, similar to the old "60/40" trick, how did they get it to work with stock rockers? Was it not enough to make any significant impact, or where other variables changed to accomodate?
12-27-2009, 07:42 PM
#63
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I think that is a contradiction. How can rocker selection have nothing to do with valve location, when the pivot and pushrod location are dependent on the valve's location?
While pivot location and pushrod location are influences on a rocker design, it seems valve location would be as well. Changing only one with a given rocker can lead to serious problems, like only half of the rocker tip sitting on the valve tip (extreme case). Therein lies my question: if they moved the valve centerlines, similar to the old "60/40" trick, how did they get it to work with stock rockers? Was it not enough to make any significant impact, or where other variables changed to accomodate?
While pivot location and pushrod location are influences on a rocker design, it seems valve location would be as well. Changing only one with a given rocker can lead to serious problems, like only half of the rocker tip sitting on the valve tip (extreme case). Therein lies my question: if they moved the valve centerlines, similar to the old "60/40" trick, how did they get it to work with stock rockers? Was it not enough to make any significant impact, or where other variables changed to accomodate?
and yes if you only change one given you will have problems-that's why everything needs to be changed accordingly
12-28-2009, 05:01 AM
#64
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I did this weekend Shawn. Probably misspelled a lot but what would you expect from an engineer, proper spelling?
Other than being able to sell the best products out there, I have no *stake* in Performance Induction. Why would you ask?
So what's going on with the heads?? Has any 215's on a SBE been tested??? If not I would be willing to test a set on the engine dyno, and chassis dyno, and then prove there power and back it up at the track!!!!! I really want some info on thes heads. Been looking for the best heads for my cam only car to turn it into a screaming H/C/I car.
Everyone wants free stuff. I guess when the utility companies, the tax man and the health insurance people give me free samples, I may be able to do that. Until they do, y'all gotta pay to play.
12-28-2009, 08:36 AM
#65
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I did this weekend Shawn. Probably misspelled a lot but what would you expect from an engineer, proper spelling?
Other than being able to sell the best products out there, I have no *stake* in Performance Induction. Why would you ask?
Everyone wants free stuff. I guess when the utility companies, the tax man and the health insurance people give me free samples, I may be able to do that. Until they do, y'all gotta pay to play.
motor is out of the car and its getting prepped for heads. I just really want info on them before i buy them. 
12-28-2009, 10:02 AM
#67
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the rocker selection has nothing to do with valve location,but rather the location of the pushrod and rocker pivot compared to the valve location.
you can use ls3 rockers on stock ls1 heads if you put the pivot location and pushrod hole in the correct location for them
you can use ls3 rockers on stock ls1 heads if you put the pivot location and pushrod hole in the correct location for them
Have you actually done this on LS1/LS6 heads? How much do you charge for the machining and the stands if they are needed?
Thanks.
Jon
12-28-2009, 11:33 AM
#68
So we agree that valve location is important in rocker selection afterall?
12-28-2009, 12:12 PM
#69
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Did they? On factory iron SBC heads, when they moved the valve .060" (a little more than the thickness of a dime), did they plug up the old hole and redrill and tap a new pivot point for the stock stud mount rockers? Or maybe if you just move the guideplates over...
Well what if you don't change the pivot point? Contrary to your last post, that valve location becomes pretty important in rocker selection doesn't it? I'm not trying to argue theory or design here, I'm just asking a simple question as to the design of this particular head: what did they do to allow the use of stock rockers with altered valve centerlines? It was a question intended to coax a little more specific info as to the design of the head, not to start an argument.
So we agree that valve location is important in rocker selection afterall?
Well what if you don't change the pivot point? Contrary to your last post, that valve location becomes pretty important in rocker selection doesn't it? I'm not trying to argue theory or design here, I'm just asking a simple question as to the design of this particular head: what did they do to allow the use of stock rockers with altered valve centerlines? It was a question intended to coax a little more specific info as to the design of the head, not to start an argument.
So we agree that valve location is important in rocker selection afterall?
how is it that you can run an ls7 rocker on both a 4.00 bore etp ls7 and a 4.100 bore etp ls7 when they have different valve centerlines?valve location doesn't determine if the rocker uses an offset or not-pushrod location does.
look at it this way-if you have a rocker setup that works,then move the valve guide .060 to the left,then move the rocker pivot and the pushrod .060 to the left-everything is still in the same location relative to each other.
01-02-2010, 09:28 PM
#74
One question i have is why do they offer a 225 version for the large bore engines 4.125 + and not the smaller bores.
Looking forward to getting a couple sets of these and would like to use the smaller runner sizes on the low 400 cube setups. Some of the set ups are too big for the 215's and not going to benefit from the flow capabilities of the 245's with the restrictive intake manifolds being used other than a sheet metal or carb manifold set up so is their anything in between or is that the only configs that will be available.
Looking forward to getting a couple sets of these and would like to use the smaller runner sizes on the low 400 cube setups. Some of the set ups are too big for the 215's and not going to benefit from the flow capabilities of the 245's with the restrictive intake manifolds being used other than a sheet metal or carb manifold set up so is their anything in between or is that the only configs that will be available.
01-03-2010, 11:20 AM
#75
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yes One question i have is why do they offer a 225 version for the large bore engines 4.125 + and not the smaller bores.
Looking forward to getting a couple sets of these and would like to use the smaller runner sizes on the low 400 cube setups. Some of the set ups are too big for the 215's and not going to benefit from the flow capabilities of the 245's with the restrictive intake manifolds being used other than a sheet metal or carb manifold set up so is their anything in between or is that the only configs that will be available.
Looking forward to getting a couple sets of these and would like to use the smaller runner sizes on the low 400 cube setups. Some of the set ups are too big for the 215's and not going to benefit from the flow capabilities of the 245's with the restrictive intake manifolds being used other than a sheet metal or carb manifold set up so is their anything in between or is that the only configs that will be available.
we do offer the smaller ports in the larger bores. We can pretty much mix and match any of our port and chamber combos.
01-03-2010, 03:42 PM
#78
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01-03-2010, 03:47 PM
#79
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I think these heads are going to be great as were the other heads Cary has done. I think they will especially shine on the larger stuff as previously there just weren't heads even like this out there!
01-03-2010, 03:50 PM
#80
Thanks
Tommy