ZX636RIDER03

I know there is a lot of threads out there that talk about specific cams for the lt1 and after reading as much as I can and learning more about them...I'm in a bit of a dilemma.

So...I'm in the process of building up a 355ci. So far, I'm going with SRP forged pistons, forged scat h-beam rods, arp main stud kit and upgraded main and rod bearings.

When i placed my order, I had my heart set on the comp cc306 which I had also ordered hardened rods and 918 springs. My plans down the road are to port my heads and learned that this cam will not reach its maximum potential with the stock heads.

After reading more into what kind of rpm the cc306 would require in order to reach its max potential, I also ordered a cc503 to tone it down a notch.

So basically I have two cams sitting in my garage and I'm enticed to put in the cc306, but don't want to regret it. Does anyone have anything they can add to this to help me make the right decision...

Thanks

94Form

I can't back my claims up with dyno numbers or track times since I haven't done either, but I will say I love my 306. Yea I'm sure other cams have better low end power, but it isn't bad with the 306 either. And when you get to the top end get ready for that.
Also I have 0 drivability issues with the 306.

LT11996

You shouldn't have any concerns spinning your bottom end high now that you're using better rods and pistons with ARP hardware. I think if anything you would regret the cc503 cam if you installed it. While it is a good proven cam, it's much smaller than the cc306. Since you do plan on porting your heads down the road I say go with the cc306.

ZX636RIDER03

Thanks 94Form, looks like you in your sig that your benefiting fully from the cam based off your LE2 heads at the top end. I plan to get my heads ported down the road. Im currently running 26lb injectors, I see that you have 30lb SVO's. Probably something else I would need to consider upgrading as well.

ZX636RIDER03

That sounds like music to my ears. This was another concern that I had with that cam which was to spin my bottom end higher on a 2bolter to achieve the cams top end performance. So it looks like I can benefit from what the 306 can provide on my stock heads for now until I get them ported later on..

Will 26lb injectors be sufficient for this cam? Need to do a search on this topic, I think I remember coming across a thread that talked about what # injectors to hp goals.

Shangrila

Chevrolet V8 305-350 (OE hydraulic roller) 1987-1999

my94blackz

Just keep in mind even ported lt1 intakes doesnt do so well over 6500 rpm........ Look at the cams at the rpm range.

RamAir95TA

Not true whatsoever. The stock LT1 intake manifold is VERY capable of performing at higher RPMs. I would say the upper limit is closer to 7000-7200, which is where I currently spin mine.

Also, the RPM range that Comp provides is grossly under-rated for typical SBCs so you have to take those numbers with a huge grain of salt.

ZX636RIDER03

This is what I've been hearing about with regards to the 306 cam and gave me some concerns about spinning the engine up within the 6k rpm range. The 306 cam is listed at 1800-5800 rpm, but I've heard it pulls well into the 6k range. I wonder if comp advertises this range with 1.5 rr's or stock stamped steel rockers.

When I look up the my old cam that I had by itself which was the lt4 hotcam, its range is the same as above, but when paired with the valve springs and 1.6rr's that comes with the kit, the range goes up to 6k.

I'll definitely be getting the car dynoed as soon as its up and running so I can get and idea of where the power drops off on the new set up.

Bersaglieri

I've ran both of those camshafts, plus a few others, and each has it's place.

What's the purpose of this vehicle? Track/daily driver/weekend toy/ miles per year?
Gearing?
Compression [static]

Plan on running stock heads for how long?
Please return/throw out the 918 Beehives or start saving for another motor.

Give me that info and I'll give you an honest answer.

KW Baraka

In my experience with the 306, it'll build horsepower up to about 6300-6400 RPMs.

But CompCams do underestimate the RPM range of their cams in LT1 engines.....sometimes to the tune of almost 1000 RPMs low. It's almost as if they're giving you performance numbers based off what the cam might do in a TPI engine.

KW

ZX636RIDER03

Thanks,

Bersaglieri

Well, you can have a car that is a jack of all trades, but master of none, unless you're willing to make big changes to the car depending on the event you're going to.

3.42's will work good with a XE503, but the CC306 is going to live a happier life with a little more gear. I ran my CC306 with 3.73's and later 4.11's. Personally if a custom cam is an option I would definitely run that over either of those Comp grinds. Lloyd Elliott is spot on with spec'ing camshafts.

What values are you using for all the inputs on the compression calc?

Running the size camshaft you are considering is about where I'd start pushing for ported heads, even if it's just the LE1 port work. If the motor is apart it only makes sense to knock it out. A CC306 and LE1's have cracked 400rwhp in the past, but a LE cam with those heads could be setup to exhibit better low end, mid range, whatever you need.

Some people swear by beehive springs, other's have lost motors because of them. Personally I don't understand the value and taking such a big risk on them. Run a decent double spring, if you talk to Lloyd he'll set you up. I ran Crane 10308-1 with my CC306 and currently run Comp 987's on my XE503. A Comp 977 spring is a decent choice as well, but I run Patriot Gold Extremes on my larger LE4 cam.

ZX636RIDER03

Prior to me blowing my previous engine, I wanted to go with 3.73's. This will be a mod that I will do further down the road once everything is back up and running. I'm going to see what I can pull off $$$ wise and contact LE, It does make sense to get them done at this time. So far the 306 with all the supporting stuff is about $500 bucks. I can return this stuff and pay a little extra to get a matched set up that will work in sync together.

Bore: 4.030

Stroke: 3.480

Heads: 54cc (For a 10:4:1 stock CR 58cc does make sense, just not sure what is correct from various sources)

Deck Height: .015

Gasket (Felpro) .039

Thanks,

Bersaglieri

Ok, if you plan on adding some gear later, something of the CC306 size would like it. 3.42 is a good street gear, but if it's more of a toy you can get away with 3.73 and 4.10 pretty easily.

The .039" gasket is your problem with compression. It's also going to hurt your quench which should be a little tighter than .054"; moving it down to .041"quench with a .026" gasket will bump the compression and combat detonation.

Assuming a 56cc head, 5cc piston, 4.100 gasket bore, .026 gasket, .015 piston depth, 3.48 stroke, and 4.030 bore that'll put you at 11.43:1 static. Have Lloyd move the head cc around if needed to add or deduct the static compression if necessary. a 54cc would make it 11.74, a 58cc 11.14. A CC306 will want more compression, but a well thought out camshaft can do more with less. These are some of the details that make or break a build. Guys who just throw crap together typically wind up with mediocre results.

If you can spring for heads, I'd do it, it'll save you lots of hassle later, added labor, new gaskets, new fluids, time, new tune, etc. It's worth spending a little more do it right the first time.

If your stuck with an shelf cam look into Lunati grinds, those are the best off shelf grinds for LT1's in my opinion. The Voodoo line is very nice, a 231/239 60122 would be a great street machine cam for a hot 355 with gears. But for a tiny bit more, Lloyd can tailor something to your exact needs and match it up to the heads.