I had someone local spec out a cam for my new setup and was wondering if anyone could give accurate advice what to expect from it as far as power delivery and drivability. New engine/drivetrain specs listed below. The cam that was spec'd is a Comp XFI 07-468-8 242/248 584 int 579 ex 113.

As much as I would like to see more potential out of the car, I don't want the car to be annoying for driving long distances. I am half tempted to get a custom cam just to make sure it has decent driving manners for our frequent road trips and cruises. This car will only see the drag strip about 2 to 3 days a year. Thank you all for any information you can share.

I think the engine should be able to rev comfortably to 7k rpm, but this is just all based on research on this project over the years... yes this project is years in the making.
-4 bolt studded block
-Eagle 4340 Crank 3.500" stroke
-Manley h-beam Rods 5.7"
-Ross Racing Pistons 4.020"
-Comp Pro Mag 1.6 rockers
-ATI Super Damper
-Canton Oil Pan, New GM oil pump with upgraded spring
-GM LS7 Racing Lifters
-AFR LT4 195 LE ported heads - 58cc chambers, flow numbers:
.200/.144/.105
.300/.198/.144
.400/.242/.177
.500/.271/.201
.550/.279/.209
.600/.285/.214
.650/.284/.218

-LT4 ported intake
-Full weight Formula w/T-top, M6, suspension upgrades
-McLeod Street Twin w/ alum flywheel
-Meziere EWP
-GM single roller timing chain
-Rebuilt 10 bolt with 4.10 gears
-285/40/17 street tires


**Thanks for all the input so far guys. One more thing to add as far as the reason for the duration and lsa on the original cam is I will be spraying a 150 to 250 shot of nitrous when I run the car.

 

To be honest I think it's a little big for a stock displacement motor, especially one that will be driven long distances. I would definately at least talk to someone about a custom grind. If you were going to build a 383, I would say it's just about right. With the setup you listed though, I'd expect that cam to be a little overkill.

 

Just to clarify the cam above was not selected with driveability in mind. This is just what I have now become most concerned with and am heavily shifting towards.

 

Keep the lift(maybe even raise it some) but drop the duration and LSA, and you will be a much happier camper in a small cube build.

 

Driveability will suffer IMO. I'd go with something a bit smaller for better street manners, more low end torque. That cam is gonna need some rpm before it really turns on.

Why not step down to the XFI 467? 230/236 duration.

 

About mid 3K range is what I have been told so far.

 

Yep, at least 3.5k . You are an M6 so have more leeway, but my stalled auto spends its most time in the 2-2.5k range if I try to drive normal. If it doesnt make much until 3.5k it will feel like a dog on the street.

That would be nice for a 383, but I think its a bit much cam for a street driven 350/355.

 

Did you ask Lloyd Elliott, who ported the heads, about a cam to go with your combination? He may steer you in the right direction.

 

with a cam like that there wil be only 2 things you can do.
Race it, and park it.

 

That is my next stop, just wanted to get a little more input on what I already had. I will more than likely get with Bret/Lloyd for a custom cam to make sure it ends up the way I want it.

 

That's what I'm afraid of.

 

Most SBC cam cards calculate lift with 1.5:1 rockers. If that's the case here, your actual lift will be 0.623"/0.618" and the cam will act even "bigger". I'd look for ~10 degrees less duration and a tighter LSA if it were I.

Rich

 

I agree. 230ish duration, 0.600" lift max with 1.6's on a 112 would make a nice compromise for performance and driveability.

 

Comp uses 1.6 rocker ratio numbers for their XFI series.