[edited by Moderator]

It is a tricky problem and I don't remember ever coming up with a fix for it. I don't remember seeing a special case for reverse only in the tuning. Maybe reverse is like Park so the idle setting for that is the same as reverse but the vaccum can drop lower? Maybe set the engine rpm for Park higher? You could ask PCM For Less guys, they'd probably give you an answer.

Hal

 

I have pacesetter headers full length on the car now. And I plan on running a stall.....I wasn't planning on changing the heads....yet.....when i go 383 I will get a set of trickflows from ai. What about the 466 comp????

 

What do you want to know about it? Just looking for other opinions?

Here's some other info: Lunati recently had a change in ownership and started in a new direction on some projects. They've begun to make camshafts with aggressive ramps too, now realizing the advantages they offer.

However, CompCams is widely recognized as the premier camshaft company in the USA and probably the world; even in an interview, Harvey Crane said so.

I'm not trying to convince others to change from whatever cam company they may prefer or begin a war. I'm just offering this information from what I've read in mags, tech articles and in researching the internet.

It's reported that Comp also has more engineers on staff than any other cam company and their facilities are packed with the technologically latest design and manufacturing equipment.

Jake

West Point ROCKS!

 

Consider the Comp 503 BEFORE any of the ones you listed.

The HOT is functional but OLD technology and leaves a bit on the table.

The XFI grinds are specifically taylored to the capabilities of beehives springs AND with Comp's rpm ranges being 500+rpms low it makes their spring recommendations questionable, more rpm means more spring needed. The guys who have tried double springs with them and actually TESTED the car find valve float as do many of the guys who use the recommended springs after some miles. They are very hard on valvetrain.

As you spend more time here you will learn that not everyone tests things before they recommend them, and you would do well to question the folks recommending parts about what sort of TESTING and RESULTS they have or that they can point you to.

Look around for MEASURED successful builds with the XFI lobes, not just guys recommending them MEASURED positive results. You wont find much.

The 503 cam I recommended is quite popular and a solid performer, lots of info out there, I recommend you look around, don't just take my word for it.

 

96, are you saying the beehives are great springs for that cam? I've heard a lot of talk about them but didn't know they were a great spring. I thought they were just being used instead of LT4 springs. Now I don't mean the best of the best, I just mean a spring that can handle a moderate and fast cam.

Hal

 

Beehives for what cam??? What Beehive for that matter?

The XFI stuff was designed with the beehives capabilities in mind, the light retainer and constantly varied coils make it a fairly stable design that does not rewadily resonate and generally can control the same cam with less pressure than a traditional spring. They could have deisgned those lobes LONG ago but cam lobe design is generally dictated by springs being available to control it. They did not have a good inexpensive easy on parts spring to do that till they began marketing beehives. If using traditional springs you will need a LOT of spring to control the XFI lobes, guys have tried it and usually ended up buying the beehives in a step stronger than Comp recommended.

Since Comp's rpm ranges are all way off their recommendations should be questioned.

 

I'm not going to allow this to turn into "my camshaft recommendation is better than your camshaft recommendation", however I must take issue with some of what you wrote. The other side of the issue needs to be voiced.

All too often a poster will ask a specific question yet will begin to received responses all over the map; diverging from the original question. I try not to fall into that trap but, occasionally, I just can't resist especially when it falls into the common sense category.

First, CompCams extensively tests the design and function all of it's camshafts before offering them to the public. If Comp says a certain spring works with a certain profile, it does. They didn't just pull that recommendation out of the air. That combination would have been extensively tested and proven to work. To assume otherwise is contrary to the common sense approach.

The basic premise is that since, (or "if" should you prefer), Comp is the premier cam company, it follows that their should be high confidence in their products. However, Comp, and no other company for that matter, can control how the product(s) is installed or guarantee whether it's fit for a specific purpose. You'll find that disclaimer in virtually all items sold by companies.

Another premise is that for a company to be successful, it's products must perform as advertsied. Should a product not meet expectations, buyers will move away to other offerings by a different company. So it's in a company's vested interest for their products to perform properly. A company cannot become the leader of any industry failing that.

XFI lobes are currently at the cutting edge of cam design. the others are fast becoming "old-school". According to James Humphrey, Lunati's cam guru "Lunati has made excellent cams, but in today's marketplace, if you stay with the same thing, you don't last." Lunati has recently gone with aggressive ramp technology on their cams.

It's not a one-size-fits-all situation. No one camshaft is designed to work with all the differing engines out there However, Godbold, who I believe is Comp's lead engineer, said the XFI is the best lobe design they've ever done.

When it comes to the valve train, far too may guys cut corners. Perhaps because of lack of knowledge, money issues or just too lazy. Take valve springs, for example: There are two fundamental procedures to follow when setting up and breaking-in new springs to reduce pressure loss. Yet seldom is either of them done or even mentioned. Then when spring pressure falls off they look for someone or something to point a finger at and blame. Seldom will they accept responsibility for their inaction. In my personal case, one of those setup procedures goes back more than 40 years when AFR first taught me; the other I learned from constantly reading.

If Comp recommends that a certain pushrod be used, it's because that pushrod has been tested and is known to work. Same with lifters, retainers, locks, etc. Yet the buyer chooses to use another pushrod, then looks for someone to blame when the results aren't as expected. Changing the ingredients often changes the results.

In all the years I've been a member of different Forums, all too INfrequently do I read posts about properly setting up valve train geometry. More attention is paid to cfm head flow numbers, the sound of an idling engine or how do I repair this or that, etc.

Here's another one, guys over-camming their engines and then complaining about how the engine runs. According to Jamora at ISKY Cams, "Most guys just don't have the experience to choose the best cam and almost always overcam the engine. Then they call and say they have no bottom end or can't get it to idle and that it's the cam's fault."

Those few who do attempt to set up their valve train geometry often resort to using un-recommended procedures in, for example, determining the correct pushrod length. Seldom are cams degreed-in and, in fact, one guy posted that it CAN'T be done!

If anyone wants to avoid problems and realize the desired results, use the recommended parts and follow the recommended installation procedures. Don't cut corners or become creative, once you do, you're on their own.

So those are just my thoughts and input. The OP listed the cams he's interested in and I tried not to allow this to turn into a free-for-all on which other cam he should run.

I've said what I had to say, so now I'm through with it. I apologize for steering off the original post.

Jake

West Point ROCKS!

 

I'll just hide in the corner with my Crane 227...

 

Does Comp Cams specs out head flows that would work best with their cams?

Hal

 

The recommended springs for the XFI cams will work inside the stated rpm ranges, BUT and this is a BIG BUT the rpm ranges are lower than we need with the LT1. Presumably this is because of the effect our intake manifold has on the powerband as compared to a typical gen 1 intake.

Most aftermarket companies test their gen 1 product and just use the info on LT1 stuff. Look at the LT1 heads, many are published with 4.125 bore because that was a gen 1 400 bore mthey just recycle the info. Same exact thing happened with Comp and the spring recommendations for the XFI lobes.

 

look I appreciate all of yalls advice....I don't want to start a war....

 

i run a cc306 and beehives in a stock headed 350 and an M6. its too much cam for a stocker but sounds awesome and i love it. whatever cam you pick, here is some advice...

if you go with NSA roller rockers and beehives, as in my experience, you are most likely going to need a shorter pushrod. the roller should sit just off center of the valve stem when valve is completely closed (just off center towards the sky). the roller should be just off center to the ground when the valve is completely open. lamens terms. i ended up going with a set of manley 1 piece 7.100" pushrods (they cost a pretty penny) but there are cheaper out there. stock length is 7.200" and puts the roller a little too much off what is recommended for my liking. lots of guys run stock length with no problem but if you are picky you might want to look into it.

best of luck!