for my 86 305tpi i was thinking of getting a comp xtreme cam , 212-218 .449-.456 112 lsa. i just found a real good deal on a crane powermax cam . 210-216 .440-.454 114 lsa. my question is with ported heads and intake and all the usual mods. 3.23 gears. is the crane cam a good cam or is there a big difference in power compared to the comp cam. i want this to be a good running street car with a good idle with the ocasional trip to the track. any recomendations would help.

 

i dont think there is enough difference to make one better than the other, the only significant change is the LCA and thats only 2 degrees.

Hopefully your good deal is on a brand new cam, you cant use a used flat tappet cam....(unless you have the original lifters, in the exact order they came off of the cam..so you can put them back on the exact lobes)

 

LSA makes it idle differently....

IIRC - a wider LSA makes a smoother idle.

If your running F.I., you will need a computer friendly camshaft.

Of course if your custom burning your prom.... just about anything can be MADE to work.

Good luck.

 

CompCams, generally, is more aggressive in designing the lobe RAMPS than Crane is.

If you take two camshafts, one from CompCams and the other from Crane, that have the exact same duration at .050 AND are rated at the exact same lobe lift, you can make a meaningful comparison.

A more aggressive ramp opens the valve quicker giving more area under the curve which translates into more torque and HP.

So using two camshafts as above, subtract the .050 duration from the rated duration. The lower the resulting number, the more aggressive the lobe ramps.

These two companies - both excellent - are tough competitors. If you read their ads each seems to sing the praises of their products and highlight the short comings of their competitor's.

Higher duration moves the power band around. For every 8/10 degrees of duration difference the power band moves about 500 RPMs.

In selecting a camshaft you must consider the engine CID,compression, etc., plus the induction and exhaust systems. They must be considered as a package/team, each complimenting the other.

Of the two camshafts you listed, I'd go with the shorter duration cam, especially in a 305.

As a rule of thumb: Let's suppose there is a PERFECT CAMSHAFT for your particular combination; but for whatever reason you can't install that perfect camshaft.

It's better to install a cam that is little too short in duration than one that is a little to long;

Better to have a little less than optimum ignition timing than a little too much;

Better to have a A/F mixture that is a little too rich than a little too lean. Etc.

Just my thoughts.

Jake

 

To add to that: better to have great flowing heads and a non perfect cam, than low performance heads with "the perfect" camshaft

slightly off topic, but heads is where its at....sorry

 

I was not attempting to compare one item against a different item, but rather to compare one item against itself.

Fuel - too much Vs too little
Timing - too much Vs too little
Camsahft - too much duration Vs too little,

etc.

Choosing which makes the biggest impact on performance is another story altogether.

Jake