Help with SBC cam selection

[NickQuick]

I could use some advice on cam selection for my Can-Am before I rebuild my 383 SBC

Right now with the engine as it the car kangaroos between 1700 and 2200 rpm which is a real pain at low road speeds. What I am trying to achieve with the rebuild is a smoother drive at low engine speeds for trundling along at low road speeds with a torque curve that gives medium torque levels at low rpm rising with engine speed to for easy access to a rev limit of about 6.5k RPM. Oh, and a little more horse power

The current cam is a Comp Cams Extreme Energy 294 (spec page http://www.compcams.com/Company/CC/cam-specs/Detai... which is a high duration hydraulic flat tappet giving 250 deg of intake duration at 0.005” and a Lobe Canter Angle of 110 degrees. I think the level of intake exhaust overlap is responsible for “charge robbing” between cylinders which sets off the kangarooing. My heads may also be struggling to flow enough gas to keep up with this cam which works up to 7k RPM according to Comp.

The Comp tech help line suggest a Comp XFI292 should work well (spec page http://www.compcams.com/Company/CC/cam-specs/Detai... it’s a hydraulic roller with 242 degrees of intake duration at 0.005" and an Lobe Centre Angle of 112 degrees which they say should give better low RPM intake vacuum to smooth delivery and good mid and top end power.

The key here is that Comp are not particularly familiar with Ultimas, so before I commit it would be really good to get any experiences that folks have had, good or bad, with hydraulic roller cam grinds for use in Ultimas.

Nick.

Engine spec.

383 SBC
10.7:1 compression
Cam - Comp Cams Xtreme Energy XE294 hydraulic tappet
(248 deg intake at 0.005”, Lobe Separation Angle of 103 degrees)
Manifold - Edlebrock Victor Junior with 8 injectors in port runners
Throttle body - 800cfm 4 choke with progressive linkage
Heads - Edlebrock performer RPM
(some port work but likely to be changed later for larger AFRs heads)
Headers and exhaust – Ultima factory
Engine management - Emerald 3D ECU, injection and ignition maps with TPS for load sensing
Currently getting around 400 flywheel hp @6.3k RPM

[bluesatin]

I would speak to Gail at American Speed as to the best setup.

[NickQuick]

Good point, they must have a lot of experiance. It isn't an American Speed supplied engine but I'll give Gail a call.

[738 driver]

Depends on the type of ignition system you are running but increasing the base timing until it loads the starter then fixing the max around 34-35 deg from 3500- will help. When engines are run on engine dyno's max HP is usually the goal, tuning in the car is a different kettle of fish.

Any of the Comp extreme energy cams should be very road tunable so long as the rest of your engine package matches fairly well.

Good Luck.