custom Ls7 cam
Even though I have been specking out cam for 15 years now. I will recommend a proven cam for certain applications. What heads, compression intended use, ect. I have gone with a proven cam for LS7 heads on my 427. Funny, it’s something I would have specified for racing. If you’re going all out try Vette air.com./Quality MotorSports (same company) or Texas speed or one of many companies with your combo? Carlos (at vettte air) has a nice 260/270 .700/.700 lift cam for ya. I am going to install a 250ish 650ish in mine. You will be surprised that you don't have to go big exhaust duration with a Fast manifold in this area cam (duration). If you’re going SP manifold you would obviously need something different, as you won't need to worry about two torque peak issues with late intake valve closing points. As a general rule that cam size on a LS7 (with all boltons) will do 600+rwhp. 620-670 depending on fuel and compression. Take off 20 or so for our non titanium and dry sump combos. Decent choice (if your going all out), but DCR is also important along with ABDC of intake valve. Or just go with a proven cam for your cubes, heads and compression.
Jim
Jim
Thread Starter
Staging Lane
Joined: Mar 2011
Posts: 76
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heads- carys 285cc, titanium In valves, td shaft rockers etc etc
manifold - carys full cnc 2 piece ls7
carb - prosystems SV1 approx 1200cfm
comp - 11.8 to 1
bottom end - callies crank,
rods etc etc
fuel - E85
adders - 200hp Nos via NX halo plate and nitrous outlet system (graeme)
ignition MSD dissy and 7531 box.
manifold - carys full cnc 2 piece ls7
carb - prosystems SV1 approx 1200cfm
comp - 11.8 to 1
bottom end - callies crank,
rods etc etcfuel - E85
adders - 200hp Nos via NX halo plate and nitrous outlet system (
graeme)ignition MSD dissy and 7531 box.
You’re going pretty big with that manifold and head set up. I personally would go 13-14 to 1 comp with E85. But, maybe you’re like me and want to use 92-93 octane in a pinch. Try vette air Lucifer cam to your engine specs (with those heads)...You have the valve train... Me...Thinks 580-620 unlocked verter (if your big verter auto). 630-670 manual. That manifold will help big time and should give you another 20-40rwhp over a ported FAST.
Now, if you were 13.5-14.5 comp I would think 700rwhp (manual car) would be attainable with those heads and manifold.
I'm also using PI heads on my combo. We will see...I'm going right at 12.0 compression (just worked out that way) on E85. I could easily go higher with shaving some off the heads, but I wanted the ability to use pump gas. And I'm using a ported FAST. I'm hoping for 560 unlocked through my 4l80e (600 locked). I always like to under underestimate the hp so as to not be disappointed.
Jim
Now, if you were 13.5-14.5 comp I would think 700rwhp (manual car) would be attainable with those heads and manifold.
I'm also using PI heads on my combo. We will see...I'm going right at 12.0 compression (just worked out that way) on E85. I could easily go higher with shaving some off the heads, but I wanted the ability to use pump gas. And I'm using a ported FAST. I'm hoping for 560 unlocked through my 4l80e (600 locked). I always like to under underestimate the hp so as to not be disappointed.
Jim
If you already have that cam try it...Looks like your DCR won't be very high, but without base duration, I can't tell ya where your at. Mine works out to 8.5 with 12 to 1. My intake abdc is like 53, I believe, don't have the DCR cal in front of me. Your 255@.050I is probably 304 base duration with a 108icl? Judging by that, your DCR is going down to low 8's with that 12 to 1 SCR.
I would shoot for something in the 8.5 minimum but anything down to 8.0 works.
Jim
