Ok,

What do you guys think of my cam selection?? I wanted something that didn't have too rough of an idle as I am trying to make my car as much of a sleeper as I can, without sacrificing too much horsepower. The cam has 7 degrees of over lap, which I think is pretty decent. The cam is Comp Cams Extreme Energy XS262S. It is a solid lifter cam with the following specs.

Lift of .532 on both intake and exhaust
Intake duration of 224 at .050
Exhaust duration of 230 at .050
110 degrees lobe separation angle

This will be going into a 454 bored .060 with 049 heads with stock valves (2.06 and 1.72 I think) and 10.2 compression ratio. Carb will be 800 cfm with an air gap intake with custom cold air intake system. Think this will do the job??? The torque/horsepower curve on desktop dyno looked really good, alot of torque in the low RPMS which is what I wanted.

Cheers

That 224/230 @.050 is really only about 216/222 at lash. Will put out a lot of torque, but I'll bet the dynamic CR is fairly high on a 454 w/10.25/1. Try using the DCR calculator from Pat Kelly, see where this comes in at. If I can come up with the int closing angle, I will get this for you.

Got the cam timing numbers.
Based on a "real" 10.25/1 set up
Comp XS262S = 8.69 DCR
XS268S = 8.526 DCR
XS274s = 8.348 DCR

Plenty of power with these. but prone to detonation.

Thanks for replying so quick

Yeah my engine builder told me I am definitely gonna have to run 93 octane. I dont mind paying a little extra coin for gas if it prevents detonation. I guess we will have to find out what she likes on the dyno. Again thanks for the help GRN69CHEV. graemlins/beers.gif

Jamie

I have been using the XE262H in my 350 and I'm pleased with it. Pretty smooth idle, works well with a 2000 stall, lots of midrange punch. I am building another 350 with better heads (AFR 180's) and I'm going to try the XS262S for smallblocks in that engine.

GRN69CHY hit the nail on the head.I run 8.6:1 DCR with old aluminum heads and its close to not liking pump gas, so be careful. I personally think you're pushing it, especially with the gaping chambers of the iron 049 heads. You'll have to deck the block down a bit to establish optimal quench, etc.... and even then I don't think it'll run ping-free on 93.

If you could widen that cam out to a 112 lsa ( I don't know how much more a custom is ), or most IDEALLY, take the next step up , the XS268 and have then do it on a 112 lsa. Now you should be at 8.4-ish DCR and that, based on others experiecne here, will definitely.

The wider 112 lsa has the added benefit of a smoother idle, later intake closing event ( hence the lower dynamic compression), a bit more torque down low. I think 112 fits "sleeper" more.

Short answer - keep your dynamic compression at 8.4 or so with iron heads, or you might have trouble.