biggrizzly

Yep!

anesthes

Actually it's going to slip a lot leaving a light, probably surge a bit if he mashes it, unless he gets about a 3200 stall converter.

On the highway OD is going to be useless, because his combination is going to want to put him around an 1800rpm cruise at normal highway speeds, but the cam is gonna flip him the bird. The car will surge, and buck, and sometimes pop through the exhaust. He will find more throttle fixes that problem, or leaving it in drive - but his temps will be up, and fuel usage WAY up.

Ask me how I know. Look at my cam.. Going BACK to the 276 this fall.
And i've been tuning for years. You can't "tune out" a big cam. And I'm not willing to go any steeper than my 3.54's in the rear. 2800stall converter too, btw.

-- Joe

BADDUCK

Glad you gave him your personal experience. I was being more subtle. It's no fun driving a cam like that on the street, especially with an auto.

anesthes

No kidding. I felt I needed to REALLY get my point across. I needed to stress how I screwed up, and I'm not afraid to admit it.

-- Joe

biggrizzly

Joe - thanks for your illustration of what to expect from a cam like this in an application like I have in mind. The guy who recomended this cam gave me absolutely no description like this. He said that this grind was an awesome cam for the LT1 and that a lot of the guys in the area tha he had bee working with are using it. I have not talked to any of those customers, so I have nothing to go on. This is why I brought this question to the Forum. Sometimes people here on the Forum take an Antagonistic approach to helpfull solutions and it is difficult to determine someone's sincerity. I thank you for your frankness. With that said, with the configuration that I am planning, what kind of cam specs might You go with?

My planned approximate configuration-

• 350 LT1
• LT1 heads, (ported and polished, bowl work and runners, valve job deshrouded - described as street & strip)
• 3.54 rear gears
• A4 automatic
• 2400 stall converter (if needed)
• MSD Opti
• Edelbrock LT1 intake
• 52mm TB
• Tune
• headers to follow initial build

Regards
Don Haller

anesthes

Well,

The cam I'm running is 'great for LT1s' too, according to a lot of fbody guys. But they are also running 6 speed transmissions, ceramic clutches, 3.73 or 4.11 rear ends, and enough nitrous to supply new england dental.

For your combination, you want something like a HR276-12. Will idle ok (ok meaning a slight lope, but not IHRA top fuel), pull till about 6,000rpm, and put your dynamic CR up enough to make some serious power where you want it.

Your combination is similar to mine, probably a hair more compression (but I need to hear more specs to determine that to be sure). Either way, with the 276HR it will be a fast combo. Get a good converter too btw. A junk converter can take out a block very quick. Or tranny, but usually the block.

-- Joe

STL94LT1

On a mostly street driven auto LT1, you're not going to like that cam. Low end power will be soft, and without a perfect tune it will jump and jerk. Especially without a steep gear.

I would look at the Comp Cams 268XFI. Specs: 218/224 570/565 113.

JAKE

I agree whole-heartedly! The above recommended cam (218/224) is spot-on, and as close to perfect as you'll likely get.

The cam the "guru" recommended has WAY TOO MUCH duration, considering your goals.

First off, 350 HP is easily attainable and you don't need NEARLY that much cam to achieive it. On a stock cubic inch engine stay in that 218/224 duration @ .050 range. You won't lose nearly as much bottom end torque, if any and you'll be much happier with it's all-around performance.

Another point is you'll probably have vacuum problems with the "guru's" cam, meaning the cam will not allow the engine to create enough vacuum for the power brakes to work reliably.

You also want to keep the Lobe Separation Angle at 112 or higher. Look for LSA at 112, 113 or even 114.

I wouldn't even put that much cam in the 415 street engine I have. I installed a 224/230 @ .050 and that engine is 65 cubic inches larger than your 350! Remember, the more cubic inches an engine has the longer the duration of the camshaft you can stick in it without all the negative side effects rearing their ugly head, like idle quality, vacuum, throttle response, etc. Bigger engines can tolerate longer duration cams as compared to smaller engines.

It's a common mistake that guys put too much cam in their engines; ("too much" meaning a cam with too much duration).

In order to better understand all this camshaft jargon, you should order one of CompCams's catalogs. You can do it on-line and they're free. In side you'll find explanations of all these terms we so commonly use. It'll also explain how they effect engine performance. Good reading.

Hope this helps.

Jake

biggrizzly

Jake,
Good Info. thanks. I have been to CompCams website but didn't order the catalog. Going there now. --->>>>
I have done a lot of research since this weekend and am learning a bit about cam timing. It's still a little fuzzy, but as I get my head around it, it's begining to make more sense.
I'm getting a real "schoolin'" on this stuff - thanks

Regards

PS
The title of "Guru" is just what I threw at this guy - I'll withhold his name to protect the innocent!! Ha Ha.

Deakins

If you are looking at minimal street time with the focus being mostly on the track experience I would run the cam that was originally recommended to you. Here's the problem with posting this question here; some of the guys on this forum like to drive their cars all over, in town, road trips, you name it and they are people that will generally tell you that cam is way too big. On the other hand; people like myself really don't get the car out on the street very often, mostly hit track days, test and tunes for the car club ect and we will tell you that the cam is fine. My combination is much more extreme than yours and making comparisons is a moot point but I can tell you that I hit the cruise nights with a solid roller having 276/284 @.50 with a 107 ls backed up with a 3200 stall. We picked this cam for it's massive mid range push (by mid range we mean from 4500-7500) that we like for our type of operating environment. I would recommend talking to your builder and arranging a ride or test drive in one of his customers LT1's with that cam in it. This will be the only way to determine if YOU find it streetable; I think you will. Just my two cents and others will certainly disagree!

anesthes

My concern about the 218/224 is how low in the powerband your putting the car. Remember, the LT1 intake has a 3" runner, its basicly a dry singleplane intake. It wants to rev to 6k. The 218/224 cam is gonna start falling on it's face at around 5200rpm. That cam is way more suited for TPI cars, rather than LT1 cars.

The 230/244 cam I'm running is perfect for LT1 engines with high gears, high stall converter, and a lazy stock LT1 head. (look at the split in the duration). I'm not sure why I tried it. silly me.

Personally I think the 218/224 is a hair small. A way better running cam, I won't argue that than 224/230 I'm suggesting. But even my 230/244 cam has plenty vac for brakes. The problem is the low RPM operation.

When I ran a 224/230 (the SLP version of the HR276) the car idled like a dream, and had PLENTY of vacume - like 60kpa at idle (like 14hg or so)
which was more than enough to get that 3600lbs superchard bird stopped after a 120mph 1/4mi pass.

This was a stick car though. With an auto he's gonna want a bit more converter.

Another thing. with the lobe seperation. I'd keep it around 112* for the duration we're talking about. The little bit of overlap helps.

Either cam would be ok for him though.

-- Joe

STL94LT1

Joe, originally I was running a 212/224 521/533 112 cam in my LT1. The peak HP was at 5800 rpms and peak torque at 4800., and it would pull strong to 6200. It made 355 rwhp and would trap 115-117 mph all day long.

However, now I'm running a 224/230 605/622 112, and it will rev forever. The new cam also has about the same low rpm streetability as the smaller cam I once ran.


Here's my 212/224 dyno sheet.

STL94LT1

Don, you are going to net very little if any power gains from that Edlebrock intake, put that money towards one of forum member's "Pete K" converters.

LT4POWR

I seriously hope this "LT-1 guru" guy asked you a lot of questions before recommending a specific cam....doesn't sound like it from your posts. Without getting into all the details of your future setup and driveability requirements, I'm very skeptical of those cam specs.

Muffin

OK, I have read it all and don't see a thing I disagree with. Key here, as always, is how is the car to be used. Big cam great for the track mild cam great for the street. My suggestion would be a cam designed for an upgraded LTx, the Hot Cam. Will be easy to drive on the street and will gain the much desired respect at the track. Oh yes, that stock exhaust ain't gonna cut it. IMHO that should have been the first thing to be fixed.

anesthes

Now that is interesting.. I guess it shows you what cam is good for one motor, may work totally different in another. Was the cam installed straight up or ? (what was the centerline?)

Which cam are you running with the 605/622 lift? Thats.. a lot.

-- Joe

JAKE

He'd definitely need a much higher stall speed converter too.

I'm running a 230/236 in the 388 CID LT1 I just built and I went with a 3000 stall converter- per CompCams' recommendation. I need every bit of it too.

Jake

anesthes

Agreed. I'm running the 230/244 with a 2800 stall and its not really getting by.

-- Joe

Fuzzy Dice

FWIW, I drive my car anywhere and have a 3200 stall Vigilante converter...street manners are impeccable...I drive the car to every drag race event I go to (a lot) and drove it from Orlando to Richmond earlier this year...

I would suggest installing a tranny cooler if you go 3000 or higher with the stall...

STL94LT1

You are definately right on that point. It is a total combination, not just one component. Both of my cams were Comp Cams custom grinds from the shop that did the heads.

Yes, both cams were installed staight-up.

The 605/622 lift cam has a mild 224/230 duration. It works very well with my CNC heads. I gained 20-25 hp from the 212/224 that I was previously running.