Taco

iTrader: (1)

I just bought a brand new, never-run set of LS1 heads. I want to get them ported and polished, probably a good Stage 2 job, with the lightweight valves from the new LS6, and Comp Cams springs and pushrods.

My first question, who would you all recommend having the heads worked by?

Also, on Cam specs, the 2 cams I have decided to make my final decision from are as follows:

Cam #1: Adv. Duration-265/271 w/ .515/.522 lift, 114 deg. Lobe Seperation factory computer no modifications necessary.

Cam #2: Adv Duration-269/273 w/ .525/.532 lift, 114 deg Lobe Seperation computer modification recommended.

Which of these two would be better for Stock displacement with a set of high flowing heads? I do not mind having the computer modified, but if the performance is not much different, would rather not.

Also, with the heads being worked, would an LS6 intake be worth the money to help get more air into the motor?

Thanks in advance,
Taco

Terry Burger

iTrader: (4)

[quote]
types of springs, size of valves (anything larger than 2.02" Intake and 1.55" Exhaust) requires the stock valveseats to be machined out and replaced with larger diameter ones = alot more labor involved
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Not to start a flame war, but it's common knowledge that on a 3.90 bore larger than 2.02 valves don't yeild you any power.

Taco

iTrader: (1)

Nine, the @.050 numbers are 212/218 for the first cam, and 216/220 for the 2nd one.

I have a guy in mind to do the porting for me, he does a lot of IHRA Pro Stock heads, and he does all of our in-house race engine heads. If he thinks he can get some good flow numbers out of them.

What are the best documented flow numbers for a set of LS1 heads?

What kind of numbers should I expect from them with a good port job, with stock-sized valves?

I had already thought about dual springs, and will probably end up going with them in the end anyway.

what about rocker arm ratio? Is there any performance to be had here, or reliability issues either?

Thanks again, and keep the info coming
Taco

guswedy

why dont you go for a solid cam? more streetable, more power, and if your already getting dual springs and stuff, you have a potentially easy upgrade....

VINCE

iTrader: (1)

Going bigger than 2.02's may not yield a noticeable power difference on a stock 346cu, but I have seen the plugs on 2.02 cars compared to 2.055 and 2.08's. The bigger valves seem to decrease detonation by a whole lot if the port job was done correctly. It seem like the high flow #'s mean very little if you cant maintain the swirl. Cant maintain swirl and from what I have heard you get an increased likelihood of detonation therefore hurting performance. It seems to me that I could run higher compression if I have bigger valves helping to decrease detonation because the swirl is getting maintained.. If I am wrong then disregard all that I have said.. <img src="images/icons/smile.gif" border="0">

Taco

iTrader: (1)

Does a solid cam not hurt reliability? It seems I have heard this before, but I may be wrong. This car WILL be my daily driver, so I need high reliability first and good, strong power 2nd. I wish I had another source of Transportation, I would much rather those 2 be reversed.

Y'all talk to me about valves, sworl and tumble and all that, i know nothing about it, but would love to learn what they are and how to contol them.

Thanks again,
Taco

guswedy

a solid cam will NOT hurt reliablity, the only thing you have to do is adjust the valve lash occasionally. its a very simple job. wont take very long to do.

Nine Ball

iTrader: (38)

Do you have the lift numbers as stated at 0.050" lift? Those are more useful for comparison's sake.

Many good head porters out there, its going to come down to opinion and availability. Just do some comparitive shopping and make sure you compare the hardware components and amount of work involved in them when checking out various shop's offerings. Look for brand names, types of springs, size of valves (anything larger than 2.02" Intake and 1.55" Exhaust) requires the stock valveseats to be machined out and replaced with larger diameter ones = alot more labor involved. Dual springs are a more expensive option, but worth it.

Yes, the LS6 intake is a worthwhile mod for a heads/cam setup. Typically 8-10 rwhp in most cases.

I've always had good luck with my MTI setups, which makes it too easy for me to support them. I've also not seen any packages come from that shop that made a customer unhappy with the performance gains. Just my own personal experience on the subject.

Tony