the CC306 is amazingly good, considering how bad it is. the ramps are very slow, it has far too much low lift overlap, too much exhaust bias, etc. but it does work. the problem is the hit in drivability, emissions, and fuel economy. for those reasons you should consider something custom that will match the CC306 in outright power, but be better in all the other areas i mentioned.

-michael

OK with all that I've read about this cam stuff I feel :crazy: :crazy: :smash: :banghead:

I plan to use the 306 , but then I hear things like the fast rap speed and so on. Question I have is, how much does engine size effect the "effect" of the cam on idle, and daily use?

I hear it's loopy and bad for a 350, then a 383, or 396 person says It's not bad in my engine. Please help me understand.

Do most agree that this 306 cam is fine for a 383+ engine?

OK with all that I've read about this cam stuff I feel :crazy: :crazy: :smash: :banghead:

I would figure you'd be closer to 400rw with that cam

DRAGRACR runs it I think

Just a thought, if you put 1.7 RR with your Hot Cam you will have a 557 lift in/ex cam. The difference to a XE230/236 is basically the exta duration, 12 on the intake and 6 degrees on the exhaust. That is a good bit of duration on the intake and not much difference on the exhaust. Nathan Plemons has doen the 1.7 RR's with the hot cam and gained about 15rwhp(please check as it has been a while), and considering the amount of work to change the cam, the rockers would be asier, as your heads should already have good valve springs. Jsuta thought. Steve

rey: this was too long to PM, and I thought it might be of general interest. I will now go out on a limb and put my "LT1 Cam Selection Ideas" out for criticism/comment. Enough of vague talk, here's "how to do it".

You don't want any of the valve events too late or too early, but just right. Did you ever drive a car with a race cam on the street (or even in the pits)? You wouldn't like it.

There is no black magic here. Keep in mind, people have been experimenting with cams in NA SBC's for many years. It is well known what is too much cam, to narrow or too wide an LSA, etc. Stick with what works, unless you have the time and $$$ to experiment.

Here's the story on valve events.

IVC: most important 'cause it determines DCR.
EVC/IVO: important because of their effect on overlap.
EVO: least important (but not unimportant).

How to pick a cam for a HR NA LT1:

1. Chose IVC based on desired DCR. Aim for ~8.5-9:1 depending on what fuel is available, etc.

2. Decide how much overlap is needed based on the intended use. Rules of thumb for a NA SBC based on advertised duration for hydraulic roller cams:

Daily driver: ~50-60 degrees
High performance street: ~70-80 degrees
Race car, occasional street use: ~90 degrees or more

3. Chose an intake duration based on head flow and desired rpm range. Better heads need less intake duration to make hp and the converse. You can't compensate for poor heads with more intake duration beyond a point. Excessive duration will kill low end torque. In general, think of 270 degrees as "small" and 300 degrees as "large". Bigger motors can use more duration. Here are general guidelines for what constitutes a small, medium, or large intake lobe at 0.050" (correlate with the advertised durations above):

Small: 210-220 degrees at 0.050"
Intermediate: 220-230 degrees at 0.050"
Large: >230 degrees at 0.050"

4. Chose an LCA based on the following.

350 stock heads ~114
350 good heads ~112
stroker, good heads 108-110

5. Chose an exhaust duration based on exhaust flow and intake duration. If your heads have killer exhaust flow and a good exhaust system, exhaust and intake duration shuld be the same. Most LT1's need at least a couple of degrees more exhaust than intake duration.

Intake center line: not enought time to go into it now. Usually, 4 degrees of advance is good, which means on an LT1 that the cam is ground with an ICL 4 degrees less than the LSA.

Lift: get as much lift as you can "afford" within the limits of HR technology. More lift = more spring = more stress on the valve train = need for better parts = more $$$. Rule of thumb: limit lift on a street HR to ~0.600". If it's not a street car, use a SR.

Voila - you have a cam.

Note: much of this does not apply to blower or N2O optimized cams. N2O cams follow the above pretty well except that they need a lot more exhaust duration. Blower cars are quite different. The need more exhaust duration and less overlap as well as a later IVC point, depending upon the static CR and fuel used, etc.

Nits, picks?

Rich Krause