Can one of our cam experts explain the difference between comp cams XR 265 hr cams. one the high lift with .550 lift and 115 cl and the other XR265 has .525 lift and less cl. HP difference,torque, rpm and why would comp cam make two cams with similar specs. Thanks PS how much hp will the high lift version make over the stock 2002-2004 z06 cam.

 

Call Texas Speed and ask them that question.

 

I'm certainly no cam expert, but I do have the low-lift 265 cam, and can comment on my experience.
These cams are torquers; thus they are very good for use with stock exhaust manifolds and heads. They were probably designed for the guy that wants a strong midrange punch for street driving, a decent HP jump, but wants to sacrifice nothing in driveability, reliability, etc. My 2000 makes 355 RWHP at 6000 and 355 RWHP at 4200 with the only other mods being a Blackwing, pulley, and tune. So, realistically, that's probably 25 HP, and 30 TQ, from the cam.
I would think the Z06 cam would be close to that in HP, but with less low/midrange torque. This little cam pulls much stronger down low, and is a blast to drive on the street. Idle has just a hint of thump, but nearly as smooth as stock. Valvetrain durability should be great with the lower lift.

But, if I had it to do again, I'd probably go with the higher lift 265 cam, and expect 5-10 HP more, but no gain in midrange torque, over the lower lift cam. With the 115 lobe center, it should have very similar smooth driveability characteristics.

Again, these are all based on my stock exhaust with Z06 mufflers.

The higher lift cam has a slightly later intake opening and closing point, which, I would guess, will raise the torque band RPM a bit, and the HP peak, while still retaining optimum dynamic compression ratio for stock LS1 heads via the higher lift. The Z06 cam intake closes much later, to mate with the higher comp ratio of it's heads.

So, both 265 cams are probably better choices vs the Z06 cam.

If you are going with headers (or heads), then there may be better cam choices for getting the most performance from your combination. Bigger cams will utilize the increased header flow better, and not be held back by the stock exhaust - thus delivering big gains vs these small torque cams.

And, yes, the tuners have monster-lift, low-duration cams out now, that are touted to be great with stock manifolds. But, that kind of lift kinda eats into valve train reliability I would think.

As always with cam selection; your attitudes may vary.

Good luck, and do mucho research, cause cam installation is a pretty big job.

DG

 

Why call Texas Speed instead of contacting Comp directly?

My $.02 is to contact the cam experts (Comp Cams) who makes and develops the product, not the shops that go through them. No offense intended to TSP and others, just my opinion. That's why Comp has a tech line with contact information.

 

Cams with lower lift have far better life expectancy with the valve train too.

but 525 or 550 lift is not much difference. both are low lift cams.

the break point is .600 of lift. most stock 243 heads just don t flow well above .575 lift and .600+ is no different then .575.

However some of these high lift cams have great flow at .200 to .550 of lift.

 

XR265 216/224 506/506 114+4
54-412-11
Good torque and very strong mid-range power. Good performance cam.
1200 to 6000 RPM Range


XR265HR 212/218 558/563 115
part# 54-424-11
XFI™ RPM Hi-Lift, XR265HR
Very Wide Power Range, Good Drivability and Excellent Response
1400 to 6700 Rpm Range

 

Herman, sent you a PM, but my system is acting up. I'll try again.
Short reply: Comp 915 or stock Z06 springs for the lo-lift, 918 for the hi-lift.
243 heads should be great with the hi-lift; stock LS1 head flow flattens out about .500 - higher lifts still help, but not as much as with the 243's greater hi-lift flow numbers.

DG

 

just to add a note, a lot of guys run these cams in their 4.8 & 5.3 trucks. a lot of them wish they'd gone a little bigger. compare that to the LS1 with even more displacement.

not saying they ain't great cams, but if you're looking for something more noticeable, you might want to look a little bigger than the 212/218

 

This might be a good one; Comp XR275HR 222/224, .566/.568 on XFI valvetrain friendly lobes. Decent bump over stock in duration and lift for a reliable street cam

 

comp 224/228 581/588 114+2


I run a Comp 224/224 581/581 112+4