Don Terrill’s Speed-Talk

Are you all seeing an influx of over cammed combinations especially with the newer better flowing cylinder heads? For example a 600hp 406 LS2 with decently ported LS3 heads with 360cfm, 12:1 compression, super victor intake, 1 7/8" headers and a hydraulic roller cam of 236/242 @ .050 and .600" lift on a 110 lobe separation. Very solid build but not huge cam timing...are you all seeing people using cams in the mid to high 250s on the intake...with everything else the same but not an increase in power?

Yep, good point.

But haven't you heard.......
If big is good, bigger is better......

"I want a real lumpy cam". How many times have I heard that one?

Hahaha....right. It is amazing to see small blocks with modern technological heads make 600hp at the flywheel naturally aspirated with small hydraulic roller cams, less than 12:1 compression on pump gas that doesn't break the bank.

Geoff2 wrote: ↑Tue Oct 24, 2017 4:46 am Yep, good point.

But haven't you heard.......
If big is good, bigger is better......

The original quote:
"If a little is good, more is better, and too much is just enough."

We built engines on that basis for many years. And always lost.

bigpoppapreston wrote: ↑Mon Oct 23, 2017 5:54 pm Are you all seeing an influx of over cammed combinations especially with the newer better flowing cylinder heads? For example a 600hp 406 LS2 with decently ported LS3 heads with 360cfm, 12:1 compression, super victor intake, 1 7/8" headers and a hydraulic roller cam of 236/242 @ .050 and .600" lift on a 110 lobe separation. Very solid build but not huge cam timing...are you all seeing people using cams in the mid to high 250s on the intake...with everything else the same but not an increase in power?

Maybe the rest of the engine was not able to go up to the rpm necessary to take advantage of the cam ?

Long ago figured to make HP there is improved air flow or a wild cam. Air flow always won. It was Bill Jenkins that explained that to me back when I was in jr high.

Belgian1979 wrote: ↑Tue Oct 24, 2017 11:39 am

bigpoppapreston wrote: ↑Mon Oct 23, 2017 5:54 pm Are you all seeing an influx of over cammed combinations especially with the newer better flowing cylinder heads? For example a 600hp 406 LS2 with decently ported LS3 heads with 360cfm, 12:1 compression, super victor intake, 1 7/8" headers and a hydraulic roller cam of 236/242 @ .050 and .600" lift on a 110 lobe separation. Very solid build but not huge cam timing...are you all seeing people using cams in the mid to high 250s on the intake...with everything else the same but not an increase in power?

Maybe the rest of the engine was not able to go up to the rpm necessary to take advantage of the cam ?

I just used this as an example but yes you are correct. If the engine is not capable of taking advantage of more cam timing because poor of compression, cylinder heads and or intake not up to snuff, etc, could lead to an overcammed combination. " I got this big mount Rushmore cam" but dragged by a guy with a similar combination but with a smaller cam thats matches the compression and intake design better.

This is not something new.

Most average car enthusiast only has an engine rebuild maybe once or twice in their life.
After the deploring '70s and '80s smog cars with broomstick cams in their engines, you can't blame some tightfunded folks wanting to have something more 'audible' under the hood.
They don't care much that their engine/car remains a sheep in sheeps clothes, with a touch of astma added (trouble breathing)...

turbo2256b wrote: ↑Tue Oct 24, 2017 9:04 am "I want a real lumpy cam". How many times have I heard that one?

About as many times as "I cant drive in the parking lot at the cruise in at 900rpm in 4th gear anymore, you didn't tune it right"

Be nice if we could sell them port EFI instead of carbs... set up a rotational misfire at closed throttle that goes away when you want to accelerate. Sound like a hot cam but drive like a stocker... which is what these guys usually want!

There's always SoundRacer: https://www.youtube.com/watch?v=b9XAC-BvUyo Add external speakers and you're good to go!

I'm actually half tempted to do it just to see how well it works. Friend of mine has that setup on a WRX. Stock cams/etc, flip a switch and it jacks the throttle open and cuts injectors semi-randomly, idles like my bridge ported 13B and makes about as much "vacuum". The engine is just skipping along barely running as it blows air through the turbo to spin it up faster at closed throttle.

Flip another switch and it also retards the timing at lot at closed throttle, and damn near builds boost at "idle" and will keep the turbo spooled up even when braking into a corner. He doesn't quite have it set up harsh enough to pop and bang like rally cars used to do in the 1990s but it's definitely an instant-on feeling when he gets back on the throttle.

But shut all that off and it's back to running and driving like your uncle's Legacy.

Yep mainly LS engines over here with big bad a$$ cams, sound great and are a crapper to drive in traffic with manual trans. Then if you couple that with a poor tune well say no more ! But its lumpy, it must be fast right

"I want it to sound radical". I had a guy wanting an L79 cam installed because he wanted a more radical sound. His engine had Iron exhaust manifolds. He wasn't open to suggestions.

I see a lot of "No, that cam won't due I need at least .550, .600, .630 or whatever lift". They vaguely have an idea of what duration is all about and never heard of lobe separation.