383 SR cam help

[dolf]

68 camaro used for DD/autocross/road racing

383 4 bolt 10.5 CR
AFR 210 El.
Dr. J ported air gap
Holley 750 DP
1 3/4 headers, full 3" exhaust
Valvetrain undecided. Crower, Isky?


I need a cam that will allow me to autocross at low rpm's without bucking badly and enough rpm range to wind her out on the road course. Can I have my cake and eat it too?

Car has a t56 and 3:73 rear. I was thinking the comp xr274r. 236/242 110 cam?

[Scott Parkhurst]

This is the engine in my car.

http://www.compcams.com/Community/Ar...?ID=1945664039

Painfully close to what you have. Check the cam I chose. It's bitchin; idles at 800, pulls to 6400, I shift at 6500, and its fine. I street drive it a lot, autocross, road course, and open road race (100-120 mph for long periods) with this car. The engine/drivetrain has been performing flawlessly in all situations. I'll be taking it to the dragstrip soon, and I am anxious to get some timeslips on it.

I also have a T56- I run 3.89s and its 1600 rpm on the fwy at 70 and delivers a sliver more than 20 mpg.


...oh- it sounds bitchin too...

[dolf]

How is low speed drivability? I would think with a cam that size it bucks a lot. I'm surprised you went that large and it is still decent in an autocross wagon. Have any idle clips? Drivability clips? How much TQ do you think this cam gives up to say the xr274r or xr280r? Does it make peak power at 6400? Would have def thought higher. Thanks!

[Scott Parkhurst]

How is low speed drivability? I would think with a cam that size it bucks a lot. I'm surprised you went that large and it is still decent in an autocross wagon. Have any idle clips? Drivability clips? How much TQ do you think this cam gives up to say the xr274r or xr280r? Does it make peak power at 6400? Would have def thought higher. Thanks!

I thought it would buck too, but it's fine with the 3.89 gears I have. If I had higher gears, it'd be bad. It's not a stocker- you do have to ease into it with throttle and get used to it, but now that I have I'm perfectly happy with it.

No idle clips, but you can hear it in the clips in my sig.

The dyno charts in the story are accurate. Like I said- I shift at 6500 and it's perfect.

Torque-wise, it delivers a lot (500 ft lbs) right where I want it (4600 peak). Look at the dyno numbers again- the grunt is steady and usable throughout the whole rpm range.

I was prepared to swap it out if I didn't like it. I ended up liking it a LOT.

[dolf]

I think I am going to go with the xr280r. 1.6 rockers and a little more compression. I hope with 10.8 CR and the ported air gap I could get 550 with decent manners and a flat Tq curve.