I have been doing a lot of research on here and I think this is my first post. This is waht I am trying to do:

My goal is 400+ RWHP using the following:

Heads
Cam
1.8 Roller Rockers
Headers w/ cats
intake

I have done a lot of research and I'm pretty sure the heads I'm going to use. They are 2.02/1.60 CNCed LS6 or LS1 heads. The thing I am having trouble with is my cam selection. The more I look at numbers the more confused I get. I know since I am using 1.8 rockers that I don't want a huge lift cam. The car will not be a daily driver but will be driven weekly with about 5-8 trips to the track during the year. It is a M6 by the way. Could somone point me in the right direction here? I need some help.

Thanks in advance,

 

400 RWHP is not a very hard goal at all. Just about any descent set of heads and a moderate cam will get you there.

If I were on a moderate budget and shooting for a weekend warrior (as in, not my daily driver) I'd go with MTI LS1 E heads with an X1 cam. For daily driver drivability I'd go with a 224 or smaller cam with a 114 or higher LSA.

BTW, why the 1.8 rockers? Most aggressive cams are designed to work with 1.7s.

 

what colonel said. for daily driving a 224 cam is the best bet, if you want more lope get it on the 112. a cam only (224+) car with full bolt ons will be close to 400rwhp depending on tune so you might not even need the heads. if you want new rockers look at the yellow terra's, comps, and patriots new set, stick with the 1.7 stock ratio.

 

Stay away from the 1.8 RR's. Just use the stock ones. I am waiting to see how my cam will do with my 2E 5.3 heads. I'm hoping for 400 myself. With cats, you may need a little bigger cam than the C1, but even a C2 may do well for you. Otherwise, it sounds like you've got a good plan going.

 

Colonel what kinda of seat pressure would you want your valves to have? Also what good would a 2.02 valve do for ya if you just lap it in and dont cut the seat?

 

Landlord, seat pressure would have alot to do with the lift and ramp rates of the cam in question as well as other factors such as the weight of the valves. I've seen numbers tossed around here and there on what's good for this and that, but admittedly, I don't have any firsthand experience with heads. I know just enough to get myself in trouble.

 

Thanks, everyone for the replies. I was going with the adjustable roller rockers to deal with pushrod length issues. If am aware that the larger cams are designed to work with the 1.7 rockers and I have been looking at the smaller cams accordingly. If I use the yellowterra rockers what kind of pushrod length issues will I have due to the smaller base circle on a bigger cam? Obviously they will have to be longer. What's wrong with the 1.8's anyway? Only thing I can see that is different is the pressure on the cam lobe is greater due to the greater mechanical advantage the valve has on the rocker.

 

There's really nothing wrong with 1.8s, it's just that when you have a ramp rate that is already pushing the envelope of even the best springs out there, going to 1.8s pushes you that much closer to spring breakage or valve float...or it could possibly push you right over the edge. With some cams and combinations, P/V clearance is already tight and 1.8s will make it tighter. You just gotta understand what you're working with so that you don't pick a combo that doesn't work.

You can get adj. arms in 1.7.

 

Thanks, Colonel, that helps out a lot. This brings up another question: If I go with 1.7's, which I prolly will after what I've heard here, is the price worth it for the adjustable arms even though they are only 1.7's? What it boils down to is you are buying the adjustability and no extra lift. What would you reccomend?

Also, you and another said stick to a 224 duration cam for daily driver. What kind of lift should I be looking at?? I looked at the Heads and cam you said and the X1 cam I believe was a 230/224 cam.

 

You don't need adjustable rockers with a hydraulic cam. I would go with the adjustables if I had a solid lift cam in the plans. The stock rockers work great IMO. I ran them all the way down into the low 10s on motor. And I'm running them now in my low 11s daily driver.

What kind of lift depends in large part on how well the heads flow at the lifts in question, what kind of springs you'll be running, and how often you plan to change valvesprings. General guess based on a really good set of heads with really good springs and valvespring changes every 25-30k? I'd go with .570-.610 or so.

The X1 is 230/227 .591/.571, btw.

 

I am really not looking to change springs often so I was thinking of keeping the lift at a max of around .560. I have heard anything above that and you get into changing springs periodically. Guess I need to look for heads that flow really well at lower lift huh

 

You will still need the correct push rod length even with adjustable rockers. If you try to adjust without the correct push rod length the rocker rollers will not be centered on the valve tips. Your adjustable rockers allows you to vary the lifter preload.