I would like to know if anyone has used there heads and cam package for the Lt1? Or if anyone has seen the flow numbers of the heads? They use stock valves and all but they must be rather bad *** to get 73 more hp from a stock head n cam vett. I know there probably not to popular with all of the aftermarket for porting stock heads but i was wondering if anyone has done this yet or seen it done. I saw a magazine get like 40 rwhp with there heads n cam, problem was they didnt use the pushrods they were supose to so they really killed the cam lift by .100 which would kill performance.

 

Read the fine print on that description of the Edelbrocks they added 1 3/4" headers too and you can bet that the baseline was on stock programming and the after was a full dyno tune. Disappointing is the reality on those things.

There are A LOT of shops that can port your current heads and offer a custom cam to get you a whole lot more power. On a stock displacement motor ported stock heads are hard to beat.

Magazines are advertizements you pay for the tests are OFTEN doctored. The rest of that sentence tells me you are a year or so worth of reading away from being ready for this pushrods do not impact lift .

Edelbrock and MANY other big name aftermarket companies are struggling to produce anything genuinely worthwhile for cars these days because the OEMs are in the midst of HP wars and have a whole lot more money to devote to R&D meaning they are leaving signifigantly less room for improvement than they did in the 80s.

 

Can you clairify how .100 over pushrods if not used will not affect your lift? If it didnt then other then selling u there pushrods, why would they reccomend these? If anything i would think that the pushrods would take away .100 of lift 1/10th of a inch from the valves if they didnt use the .100 over ones. The rest of what you said makes sence, but if u could calirify that last part. Thanks.

 

Pushrods are just a link in the valvetrain. The only things that affect lift are the lobe, the lifter plunger, and rocker ratio. The pushrod is just a straight piece of tube from the lifter plunger to the rocker.

Maybe this will help http://auto.howstuffworks.com/camshaft5.htm

 

I must disagree. If you change the length of your push rods it will most definetly affect the valve train. The reason Edelbrock recommends .100 shorter push rods if you are using stock rocker arms is this. The lncreased lift of the Cam will cause the rocker arms center slot to hit against the rocker arm studs. With hydraulic lifters this is not a big problem if you are just putting around, but but at 6,000 rpm it generates enough force to break the rocker arms. The Edelbrock Performer LT-1 head and Cam setup is very good, but if you are going to use it I suggest also using Competition Cams Pro Magnum steel 1:6 ratio rocker arms. Good Luck.

 

Edelbrock is not trying to sell pushrods. They dont even sell a pushrod in that length. I know I tried to buy some from them. If you use stock rocker arms you must shorten the length of your pushrods to prevent the rocker arms center slot from striking the mount stud. Even with the .100 shorter pushrods it will make contact at high rpms. I broke two rocker arms before changing over to roller rockers.

 

I am not saying pushrod length is unimportant I am just saying it does not make lift as the original poster believes. I understand what you are saying as far as them recommending screwing with valvetrain geometry to avoid bottoming the slot, but that is halfassed at best, the rocker should be setup centered on the valve not pulled back to avoid stud problems.

The fact you are disagreeing with me about pushrods not giving more lift is PROOF you are not knowledgable enough to give an intelligent review of those heads and cam.

What evidence have you seen to show this package is anything but a joke. Their ads are all the proof I need to see they are a joke.

Sounds like you bought their marketting BS and now have to defent your uneducated MISTAKE. My whale of a Caprice goes 13.2 on stock iron heads and a ZZ3 cam with less lift all round and 10degrees less intake duration than that cam, that was one night out after the 1.625 headers too, there is some more left in the combo. Now that you found this forum maybe you can LEARN rather than just believe marketting BS and magazine articles. Seen it MANY times where someone who thinks they knew what they were doing finds forums and then has top relearn everything they thought they knew a lot of guys here sharing they sucesses and failures, cumulative knowledge is what make man top beast on this ball of dirt, if we didn't learn from others only a fraction of us would ever even master fire.

 

I have used this setup and am very pleased with it. The valves and combustion chamber are essentially the same as the stock heads. The advantage is in the increased size of the intake and exhaust ports, and the lift and duration of the cam. I can't say how much HP gain they produce because I have not dyno'd my car but they do improve performance. Also consider a larger then stock throttle body and headers. The idea is to let the engine breath better and you wont see the full potential of the heads/cam setup if you leave the other components stock. Good luck.

 

I'm not defending anything. I don't need to. I am disagreing with your assertion that changing the length of the pushrods will not affect lift. Anyone who understands high school geometry knows many things are factored in to this. Such as; cam lift, push rod length, and rocker arm ratio. I am far from knowing it all, and more than willing to learn. That is why I joined this forum. But I also know an overinflated ego spewing BS when I see it.

 

I bet you think connecting rods affect stroke too?

Are you honestly saying that given a PROPER rocker that does not bottom out and force the plunger down a pushrod can offer more lift? I am saying proper parts not the halfassed running the wrong rockers thing and screwing with ushrods to bandaid it.

Pushrods are an important part of the valvetrain but they are just a pushrod not a lever like the rocker. It is the lift applied to the lifter by the cam lobe combined with the lever ratio of the rocker that makes lift.

In extreme cases of valvetrain geometry change I could maybe see a couple thousandsth(not enough to worry about) change from pushrod length changes BUT NOT if the pushrods are the right length centering the rocker tip on the valve tip.

 

Too much noob misinformation in here....

Pushrods are JUST A LINK.

THey must be the PROPER length for correct valvetrain
geometry.

For the money, Edlebrock heads suck.
They are better than stock, but for my money,
Ported stockers will outperform them any day of the week.

Much reading to be done still noobs!
The search button will become your best friend

 

I was attempting to answer 93LT1's question about why Edelbrock recommends .100 shorter pushrods. They first recommend roller rockers but also advertise that you can use stock rockers if you shorten the length of the pushrods by .100. Experience has proven that .100 is not enough to prevent the slots in the stock rockers from contacting the mount stud and breaking at high rpm. As I told him in another post it is best to use roller rockers. You are correct in saying that the cam lobe and rocker ratio have a far greater impact on lift than the push rod. But changing the length of the pushrod WILL affect the geometry of the valve train.

 

It affects geometry not lift.

 

You may think pushrods will affect lift, but it will not. This is something you have to accept. Let me try and explain. It wont effect the lift because the rocker arms are adjusted TO the pushrod. If you have ever set your valve lash you can get a better idea. As far as eddlebrock heads, Id set just get your stock ones ported, Im sure many people know good reputable people to go to.

 

Stay On Topic!

 

The guy who said he is using edelbrock heads n cam, how much of a difference did it feel like? Ill just find out myself why they need to do that to the pushrods, thanks.

 

They very well need the shorter pushrod for proper geometry.

http://www.edelbrock.com/automotive/2108graph.html

Guys are getting more power than this TO THE WHEELS through automatics with ported stock heads and a custom cam, heck even the LT4 HOT kit most of us agree is overrated(popularity wise) does better than this. The note is right in the picture too where they added 1 3/4" hears at the same time, given the LOW original numbers from the Vette I would say it was likely manifolds I mean bolton guys can top 300rwhp and this is a flywheel chart, advertizers do not use rwhp charts because the 15-20% drivetrain loss is not understood by many people. Some of the vendors here will use rwhp numbers but they are targetting a more knowledgable crowd.

 

everyone talks about these heads n cam, but no one has really used em. I would love to see a dyno of a full exaust and intake with these heads n cam. It would be interesting to see if edelbrock is full of **** lol.

 

Point well stated and taken. Also, porting the stock heads is a great idea, if you can find a machinist in the area that knows enough about it to do a good job. As I said before the main difference between the stock and Edelbrock heads is the porting. Thanks.

 

Maybe they are, maybe they are not. I'll let you know after I get it dyno'd. The difference feels significant, but seat of the pants perceptions aren't worth much. The numbers will tell the story.