didnt know where to post this. but what cam do you think is the best sounding like what seperation on the lobes. i myself like my 118 degree lopey cam

 

This is over simplifying it, but the tighter the lobe seperation, the choppier the idle is going to be.

For example, a stock 5.0 mustang (I'm using what I know here) has a lobe separation of 115 degrees. My old cam had a 112 degree lobe seperation and it had a mildly choppy idle. The new cam is significantly tighter than the old one and the bitch sounds like it's about to cut off when it's idling.

Don't choose a cam based on how it sounds at idle though. There's so much more to it. I'd suggest reading http://www.wighat.com/fcr3/camtruth.htm when you have some spare time.

 

no it was just that my friend got a new cam in his 67 bu and when i heard it i was like holy crap it sounds nice

 

I was always under the impression that the "lopy" cam sound was created by large duration cams. Im a bit lost when it comes to lobe separation......

 

The lopiness of a cam comes from the overlap of the exhaust and intake valves. Lopiness is bad it means that the engine is running bad and ineffecient. The are several things that effect overlap and lopiness the lsa and the cam duration. Both have and effect on the amount of overlap the cam has.

 

Comp 280H: 280 in/280 ex, 230 in/230 ex @.05, .480 in/.480 ex lift, 110 deg. lobe sep. :hail:

 

Comp cam XE268H, nice and choppy idle. Sitting in gear idling 600RPM its nice. I can't imagine the 274.

 

XE 274 with 1.6's..... yeah buddy.

 

CompCam's Magnum 294S.... soon
Just need to get a 350 block that isn't cracked

 

and thats why big cammed cars can get OK hwy miles, but when at low RPM stop and go traffic, they suck gas like crazy....

 

I myself have been reading like a madman since I just bought my first 3rd Gen and I want to add to Joc's question. I too like him, want a nice lopey sounding cam. I was looking at the comp 270H in Jegs.

After about 5 hours of reading here, I am wondering if I well get a nice choppy idle (not about to die idle) with that cam. I wonder about computer correction?? Also, I do want a nice low tone semi-rough idle but not a complete disregard for fuel efficiency. I have the LB9.

So is there a happy medium for us 3rd gen daily drivers?

(sorry for the semi-hijack. thought this stayed on topic for Joc as well as me.)

New to the site - great place for info!!!

 

That thread was 3 years old... No point in digging up a super old one like that, might as well have started your own...

ok, you've got a lot to learn, but you're in the right place.

1) put your car info in the sidebar, in your personal info page.
2) Go to the FAQ forum and read about souping up a 305. Read any FI, or TPI specifics as well. (hint, TPI is great for low RPM power, don't fight it, work with it, that is what gives you the big grin of burning rubber, etc).
3) read my sig link, I have a cam write up in it, should give you some info.

Then I won't number any other points - LB9 needs a computer controlled cam, or else it'll run heinously bad. Unless you're super comfortable tuning chips. Comp270H? boy, where did you get that idea? Straight pattern cams work well on heads with close to equal intake/exhaust flow. Well, closer then what you have. Your heads flow far better intake than exhaust, that lends itself to working well with split pattern cams. Dual energy if you like the "old" style cams that have hurtin' low lift, and if you enjoy going slowly, or extreme energy if you like words that have an X in them. (they're cooler). But seriously, they also work better. XFI cams would also work in your case IIRC.

A cam shouldn't be your first "go fast upgrade". If your sole purpose is a choppier idle, pull off a spark plug wire or two, and pull out your check engine light. hmm, actually, I should copy this advice to any others that post about wanting a choppy idle in a TPI motor hahahaha

 

DOH! Did not realize the thread was that old or I would have started my own. I guess that is what happends when you dig through search results for five hours trying not to ask questions that have been beaten to death.

Yes, I do have a lot to learn. My experience is with Jeeps/suspension/gears/lockers etc.

I got that idea from a friend who has a done a lot of engine work on older cars. I don't guess he took into account the newer setups.

As for the sidebar, I was gonna wait till she sat in my garage before actually posting the car notes. It should be here November 20th or so. I just JUST sent the money.

And forgive the new guy. I am trying to avoid sounding like a complete moron. But apparently with only a thimble full of success.

Thanks for the info.... When it comes to cam dynamics, I really do need a mother hen's wing to cower under. I don't want to make a mistake.

edit: Ohh, and the reason being is I know the car is going to need a valve job, so I thought while I was into it, I might as well make her sound a little cooler while improving the performace a slight bit.

 

comp cams magnum 306S


http://videos.streetfire.net/video/c...690129f3d7.htm

 

That sounds great.

 

I've ran a 270H comp on a 305 before it had a real nice sound to it. Lopey but made great power all around. Im sure ir would be a lot more mild in a 350 with the extra 45 cubes.

 

He's got a 305, a TPI 305, the LB9. I wouldn't go big on the cam.

Don't worry, lots of newbs show up here, it's a great place to learn. Just don't get cocky or anything, and don't insult anyone. Lest you go the way of "therckid" or "mars22" or someone...

TPI motors have a "tuned port" intake runner design. I'm not an expert on it, but you're well versed in the search function (good job!), so make use of that. TPI motors were optimized by GM to make power in the 3600RPM sorta area. They run out of breath at 4500RPM, and no amount of cam can change that, only a new intake ($$$). So might as well compliment the motors powerband, rather than fight it. A compxe256 or the computer compatible version would work wonders.

 

Whoa, guess I last posted in this when in the middle of getting my engine done. Here's a little update I had just put a new carb on the night before so it wasn't running exactly right.

 

Actually just hook full manifold vacuum up to the EGR valve. Your engine will still make good power @ WOT and lope like crazy at idle and even cough, hiccup at low throttle like a big cammed engine. After all lope comes from overlap which allows the engine to self EGR.

 

Actually I like to see newbs using that search feature and if on topic, no harm in bringing up a dead thread or three. It'll cut down on the search result clutter.

 

It also cuts down on the huge number of new threads that go something along the lines of? What cam for a 305, (Version 10,001).