I bought a lightly used LS6 454 crate motor, and I need to pick a cam for it.

454 cubic inches
10.2:1 compression
Iron rectangular port heads that flow like this
Edelbrock TR2X tunnel ram with 1200 to 1320 cfm of carburetion (runner length is 7 inches, just like a single plane)
It will be run with open headers at the track
Trans will be a Muncie M21 4-speed (2.20:1 First), which only drops the RPMs about 25% on shifts
Rear is 4.10:1. I'll almost certainly need more, like maybe a 4.33:1
Tires will be between 26" and 29" diameter, whatever works
Car is 3485# with me in it and a half tank of gas (SBC/TH350 combo)
This is going in a 1970 Nova, so it has a leaf spring rear suspension. Right now I have 90/10s up front and slapper bars in the back. Yes, I know I'll probably have to do alot of suspension tuning.

Stipulations and notes:
I don't want to shift at more than 7000rpm
Vacuum is not a concern (the only vacuum line will be the one to the distributor)
The cam can't have more than 0.600" lift because the rockers won't take it
The cam must be a solid flat-tappet design
This is a dragstrip car, not a multipurpose car

 

The multiple cam choices from all the manufactures won't make a big difference if you're limiting the lift to .600. I ran a Comp Cams 11-613-5 solid flat tappet with only .637 lift and oval port heads and about 10:1 compression into the 10's.

From what you want and the limitations you're putting on the engine, a Comp 11-604-5 is about the most you can go. The 11-613-5 is about the biggest flat tappet cam you can use before getting into roller grinds but you'd need to modify the heads for the increased lift to use it.

 

Comp Cams 11-678-5

 

OK, I really need to pick up a new catalog. That grind looks good for your combination and it's not in my catalog. Just goes to show how many new grinds they add each year. It's easier to flip through a catalog than sifting through online pages.

Did a quick search on the CC web site. The 11-679-5 is a bit better since this is a strip only car with a tunnel ram.

 

As for your tires/gears, stuff the tallest tires you can into the wheels wells then calculate the best gears to use.

 

I want to get as close to 0.600" lift as possible because lift will only help. For the duration, the concensus (online and in person) seems to be to keep it under 260° @ 0.050"
What about LSA? The majority of cams that fit my requirements seem to have about a 110° LSA.

 

I was going to suggest that cam, except that he specified a 7000rpm limit.

 

So the 679 goes to 7200 and the 678 only goes to 6800. Shifting at 7000 won't make a huge difference in either. You can easily short shift the bigger cam and still make more power.

 

Anybody have any opinions on LSAs?

 

Here is a good option from crane..Part Number: 134691 Grind Number: F-290-2 (REPLACES CC-290A)

 

In what sense?

I mean, that's kind of an open ended question. It's like asking; "Anyone have any opinions on Lift?"

 

OK, let me rephrase it: anyone have any opinions on what LSA I should run?

I see a thread in Advanced Tech where I might post some other questions too.

 

LSA, by iteself, is kind of meaningless. Sure, it has a direct impact on overlap, but a cam is a package, where the grinder has thought out the entire combination of lift, duration, LSA, ramp speed, overlap and intake vs. exhaust specs. Every one of those specs has a direct impact on the other specs. Ubless you have quite a bit of experience with cams, how are you going to know what to do?

Basically, if you're bolting on a set of "off-the-shelf" heads, then you should just select an "off-the-shelf" grind that best suits your needs. If you have a set of custom heads, then ask the guy who did the heads to suggest a cam. Many of the guys who do custom porting already sell their own custom grinds, which are well suited to the heads they're selling you.

 

LSA is kind of a hard number to suggest. A street cam is in the 112-114 range to keep a smooth idle. As you get into more of a race cam, the LSA moves into the 108-110 range and I've even seen some 106 SBC cams. As you move up to a ProStock cam, it's back to 114.

A Harley cam has a 106 LSA but then that's what works best in that engine.