Comp cams

[hodgeee]

I don't know if you guys have seen, but on Horsepower TV they showed in the parts section that Comp Cams has come out with three direct replacement cams for the Hemi motor.

One gives 25hp and and 15lbft of torque, but increases the down low torque big time for pulling or towing, obviously for the trucks.

another makes 40hp and 25lbft and gives stronger midrange power and torque,

the last gives 65hp and is setup for higher rpm running with little loss of down low torque or power.

All are designed to bolt in without any computer tuning needed. I then saw it on Comp Cams website, and then I saw an article in HotRod magazine about it, and that how all the cams use the stock valvetrain.

This sounds like a nice power adder that won't push things too far on the car like the tranny and the diffs.

Does anyone know how hard this would be to install on the car, and could it be done without having to pull the motor?

[hodgeee]

better yet, here is a link to the site.

http://www.compcams.com/information/whatsnew/NewsDetails.asp?ListHistoryID=-2099658896

[maneval69]

Take note of the second paragraph in this pdf file.
cam dynos (http://www.compcams.com/Information/WhatsNew/Files/COMPXFICamshaftFlyer.pdf)

In the August issue of HOT ROD magazine the dynoed a 5.7 crate engine. The rev limiter was set at 5700 rpm.
Here is the interesting part. The stock crate engine dynoed at 376 hp@ 5700 and 372 ft.lbs @4700 rpm
This was with a stock truck exhaust manifold.
They put on a set of full length headers made for retrofitting the crate Hemi in to 67 and up a-bodys.

Then the engine dynoed at 393 hp @ 5700 and 390 ft.lbs @4700

I don’t know how Comp Cams got past the rev limiter because the Hot Rod could not. After a day of trying to tweak 400hp out of it by fooling sensors and raising the fuel pressure they ended up with a best repeatable number of 398hp@ 5700 rpm. They believe 400 is easily obtained by raising the rev limiter to 5900-6000. Pretty good for a truck cam that pulls 21 inches of Vacuum at idle.

Comp cams said they outfitted the engine with Beehive valve springs and upgraded the exhaust when they tested the 260 cam. Of course they don’t give the exact hp numbers but from the graph it looks like about 405hp @5600rpm and 408ft.lbs @ 4700. How much of the HP gain was exhaust.

Looks like its not much better than stock. Only 12 hp and 18ft.lbs.
I also bet Comp Cams used a generous correction factor. The Hot Rod article used SAE standards for correction which is conservative.

The 268 cam showed about 420hp @ 5800 rpm.
And I don’t see a 15 hp difference between the 268 cam graph and the 273.

[needasrt4]

Comp only tested on an engine dyno, in real life they have not been able to get vehicles to run right, having idle problems and running very rough. We are pretty sure we have found a solution to this, I will be posting pics later. Install starts probably Thursday or Friday and hope to be on the dyno Next Friday.