Absolutely. Tell the head mfr you buy from what cam youre using so it has the right components/pressures/spring height set up. Most of them will do it for you if it isnt what you need already

 

YEP here's a shot a little shy of 7K.......



Ported stock heads with 7/16 arp studs and CC 1.6 Promags in 3rd gear
threw a 3500 stall vig converter and a 3.45 rear....

Mild mannered around town so my daughters occasionally drive it to high school.



MIke

 

6500rpms is not a problem. If that's what you want to do, go with the 195's to feed the higher rpms. Just get everything setup properly if you want to turn it that high very often.

Note, on the AFR195 Webpage, there's a clear explanation of what they recommend for 6200+ rpms. It's an ungraded spring set and hydra-rev kit. They also show what the hydra-rev kit is on another page. (From what I gather, it stiffens the studs like a stud girdle and increases spring pressure.)

Another option would be to use shaft rockers.

The overall goal is to get good control of the valves so they close properly (for good HP) and don't beat up your seats.

Edit: And, you probably want to go above the LPE219 cam I suggested for a midrange cam. Get something in the 222-224 range -- like FireVette used.

 

Sure did! I simmed like crazy primarily zeroing in on what changes gave what results. Duration, LSA, ground-in advance, torque curve, duration split, DCR, effect of TB change, on and on.

Biggest task was tracking down the most accurate numbers I could - you know, the old "Garbage In - Garbage Out" way of thinking. When I found differing numbers, like head flow numbers, I averaged them.

I used Engine Analyzer Pro's software which I found allows the most entries of the engine specs than other sims, like the one on CompCams' site. Comp's program is a good starting point though.

Took a LOT of time but the end result did tell me which changes gave which results.

In addition to that, I tracked down several interviews conducted with the head engineers from a few different cam companies to get their thinking on various things on cam selection. Some of it was a re-hash of what a lot of use have read in the past, but some was pretty eye-opening. Of course, if you haven't seen that stuff before it will be very helpful.

A few mags conducted some pretty extensive interviews and wrote articles for their mags. Since I read them last summer when I was doing my research, I suspect those interviews may be on the mag websites by now. Good Reading!

You could first check the sites at GM HIGH TECH PERFORMANCE, POPULAR HOTRODDING, ENGINE MASTERS, etc. I have the most recent edition of POPULAR HOTRODDING and it has a long article on cam selection too. You might want to grab a copy.

One of the things that stuck in my mind is what ISKY said when interviewed. He made the statement that a single pattern cam will ALWAYS make more torque than a dual pattern cam. I'd never read of someone being so emphatic on that point.

It's GREAT that you're doing your homework on this, unfortunately too few do. A cam that meets on person's expectations may not necessarily meet another's. Remember, you can mix and match lobes, LSAs, etc., to fine tune the specs and the custom ground cam I bought for my son's cost no more than an off-the-shelf cam.

With all the thousands of lobes available, it can become a daunting task so you can merely get an OTS cam that'll be excellent. It would have gone through all the R&D and all the accompanying parts - like springs, retainers, pushrods, etc., already spec'd for that specific cam.

As is always the case when a question like this comes up, there will be differing recommendations, so you won't get universal agreement.

What I did was to sit down with my son (since it was his car/engine) and discuss what, specifically, he wanted out of the cam swap. I made a listing of what he told me, then we prioritized it; listing the most important thing first then on down the line. Gave me a plan.

Then, based on that prioritized listing, I knew what to look for as I began the research. Remember what the Admiral said in "Hunt For Red October" "What's his plan? A Russkie, son, doesn't take a dump without a plan". LOL

Hope some of this helps.

Jake

 

Good points, Jake. As you point out, there's tons of options when it comes to choosing a custom cam. But it doesn't have to be THAT complicated.

I hope you'll confirm (as with my simulations for my build) that small changes of, say, 4-5 degrees don't really make huge differences in power level. So, the difference between a 214, 218, 219, 222 duration cam isn't going to be earth shattering. But there are some guidelines that are good to consider.

If you're not going to race (much), consider picking the smaller cam (of two choices) to get the best driveability. Same is true when looking at overlap/LSA (IOW, go conservative). With the 195's and their stellar flow numbers, I think that's even more true.

One more thing. Isky's generality about single-pattern cams isn't always true either....sometimes having some REVERSE split (where the intake duration is bigger than the exhaust duration) will provide the best torque! LOL For example, long-tube runners need more duration on the intake side -- when a good exhaust system is installed.

Torque, btw, usually refers to better low-mid powerband. While HP is traditionally used to refer to high rpm power -- but both are expressions since torque and HP run hand-in-hand. IOW, you can still get good HP with a single patten cam.

 

Thanks for all of the great advice guys! This is really helpful. I'm not quite sure what a few of the terms ya'll have mentioned mean, but I'm working on it. Real quickly, can someone explain the following:
Duration, LSA, ground-in advance, torque curve, duration split, DCR, effect of TB change, studs, shaft rockers, 214/218/222/224 (I know the higher number is more geared for top end power), duration at .050 lift. Basically can someone just elaborate on everything there is to know about cams
Sry guys, I'm young haha

 

Do a quick google search.. Chevy High performance always has some good articles on camshafts, Comp's website has some too..

http://www.chevyhiperformance.com/te...ics/index.html


LT1

Wallace

 

Thanks man! That was very helpful!

 

Also this is one of my favorites to get the basics.

 

The links above should explain alot. Cam basics and terms are definitely covered in those links.

You don't need a TB change with a 350 motor. Studs hold the rockers in place in the cylinder heads. Shaft rockers are a different (more expensive) type of rockers for high-rpm use. (They're mounted on a long shaft in the heads vs on those studs I talked about.)

Duration at .050" lift is often looked at as a guage of how agressive a cam is, how useful it really is (where it really flows), and to determine overlap characteristics.

SCR = static compression ratio, DCR = dynamic compression ratio. Read this link to understand compression basics.

 

Seeing that I'll get more lift with 1.6:1 RR's, would it be better to go with those over 1.5:1?

Also, I don't plan on revving to 6500rpm, maybe 6200 max (especially if I'm buying a midrange-strong cam)

 

Just read all of the articles. The only thing I'm confused about: valve lash. What is it (I guess it has something to do with the timing of intake/exhaust valves opening and closing when set at the base lobe or "heel" of the cam)? Why is it so important?

 

Valve lash is the gap between the top of the push rod and the rocker arm. It just needs to be adjusted correctly (via rocker stud) to minimize wear/sound while maximizing power output for the motor.

With hydraulic roller cams, lash is set to zero (e.g., no gap). Don't worry about this if you're having someone else build your motor.

 

Good sticky on cam selection here or here.

 

So seeing that I'll have longtubes when I purchase this, will I went a cam with different intake/exhaust lift?

 

Duration and overlap are bigger factors for a car with vs without headers. The lift I suggested for AFR180s or 195s will be a good choice with or without headers.

FWIW: Lift is more related to how much air you can get thru the intake path and what you motor can "use". Getting exhaust out is also important. Since headers make evacuation easier, less duration and/or lift might be possible/desireable (which is why I suggested a single pattern cam with headers/AFRs).

 

Alright thanks. What cam do you have?

 

Btw, on the AFR 195's, do I want the street flow or competition version? Is there are significant difference for $700?

 

 

Seems like there's 10cfm difference IIRC. And, normally 1cfm can generate 2hp. That means you'd have the POTENTIAL to generate 20 more HP with the comp heads. But, you might have to turn more rpms to get it.

My cam is a 214/214 .510/510 with 1.5's. With the 1.6rr I'll use, it's closer to 216/216 .544/.544 with 111LSA. Very slightly milder in lift/duration than the SR cam. Peak will be at 5800 with the 195's