MaroonMonsterLS1

Here goes again. My buddy seems to think I actually know what I'm talking about when I discuss cams. I like to think I know just enough to get me in trouble. And apparently, that's exactly what I did (it's ok, I like hanging out here). He'd like me to spec him out a cam for his ride.

The setup:
SBE 5.3 LM7
Gen IV Flat Tops
.036 Head Gasket
Stock Chamber 862 Heads, Intake valve opened to 2"
Sums up to around 10.9:1 Compression
Truck Intake
Headers
Future 200 Shot.

3600 stall, 4.10 gear, 3400 lbs

Street Driven but far from a daily.

My Current Idea for specs:
228/236
.607/.614
113+3
LXL lobes.

This would put the intake close event at 70 degrees, yielding 8.3 DCR. 58 degrees overlap at .006, 6 degrees at .050.

What say you internet?

Darth_V8r

iTrader: (4)

That can is virtually identical to what I removed about a month ago. 227/236-112+3.

It was a great cam - for a 5.7 with 11.65:1 CR and aftermarket heads.

For a 5.3, that might be a bit on the large side. Especially with only 10.9:1 CR and stock heads. I'd recommend dropping duration four degrees on each side, keep the 113 LSA. That'll get overlap down to 2 which will make that 5.3 much more manageable. It'll also increase DCR a little bit for more midrange punch.

I'm on my phone so no cam calculator handy. My gut tells me to only run two degrees advance vs three to help it rev.

So, 224/232-113+2. But if you have a cam calc handy, play with that advance number to get you 8.5 to 8.7. I honestly wouldn't go bigger than that on a 5.3 unless it was going into a light car like a RX7 or something.

Also, skip the LXL lobes. In fact, skip comp. call cam motion. Kip will grind you whatever you want on lobes that will make more power and be easier on the valve train. He also puts each cam on a cam doctor and sends the report. I've never had one more than 0.1 degree varied from specified.

roth2000

Your definelty in the ballpark with that cam just make sure your realistic when it comes to what your looking for. Lots of great sponsors on here to give you more advice but I just went with a cammotion cam and can't say enough good things about it.

MaroonMonsterLS1

That 3400 might be a high estimate. It's going in a fox that will be partially gutted.

I agree, the specs are a little on the large side, especially for those heads (might be fine with 243's) so I might look at doin the math and dropping it a couple degrees.

As far as the comp lobes go, I just appreciate that they have their lobe catalog easily accessible. Most of the calculations I do are at .006 and having them in front of me is certainly handy. With such variances in ramp rates, speed off/on the seat, etc...its just so hard to guess what those specs are truly going to be from cam motion, tick, etc. If I use a ballpark figure, i just add 50 degrees duration to the specs at .050 and call it close, but that can often be off.

Say I throw arp rod bolts on those gen IV rods and spin the thing to 6500 maybe even 6800...the larger cam, especially with the exhaust duration under spray, would start to shine more than before correct?

roth2000

A larger cam will most likely shine at higher rpms as long as you have the valve train stability to allow it it do so. That being said you will be giving up more hp and torque under the curve for the most part. If it's mostly track driven then definelty consider the larger cam, otherwise I'm with Darth about the size being a little large. Im sure cammotion can give you the specs your looking for other than .050 if you really interested. Like he mentioned the provide a cam Doctor sheet with every one of the cams they grind and you can get any duration/lift combo you want.

Darth_V8r

iTrader: (4)

Kip will give you the 006, 020, 050, and 200 lift numbers if you want them. Attached a sample cam Dr report.

speedtigger

iTrader: (16)

That sounds like a really nice set of specs for that build. It would be even better if Cam Motion ground it for you, but I am biased.

MaroonMonsterLS1

So does anybody with a similar setup have any slips they'd be willing to share? Or dyno graphs (numbers are ok but a picture is worth a thousand words right)

I'm wondering if instead of changing duration, i put it on an earlier ICL to bump dcr and spread out the LSA a little bit to get it to carry through the rev range without trailing off. Essentially leave it big to move the air, but change when it does it.

I know that will kill a little bit of the lope he is looking for, but I don't think he'll give a hoot if this thing hauls ***. I don't car about the sound at all...Speed>sound