I've read & researched the cam threads...503 or 306...
#1
I've read & researched the cam threads...503 or 306...
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
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
#2
Re: I've read & researched the cam threads...503 or 306...
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.
Also I have 0 drivability issues with the 306.
#3
Re: I've read & researched the cam threads...503 or 306...
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.
#4
Re: I've read & researched the cam threads...503 or 306...
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.
Also I have 0 drivability issues with the 306.
#5
Re: I've read & researched the cam threads...503 or 306...
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.
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.
#6
Re: I've read & researched the cam threads...503 or 306...
#8
Re: I've read & researched the cam threads...503 or 306...
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.
#9
Re: I've read & researched the cam threads...503 or 306...
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.
#10
Re: I've read & researched the cam threads...503 or 306...
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.
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.
#11
Re: I've read & researched the cam threads...503 or 306...
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
#12
Re: I've read & researched the cam threads...503 or 306...
I've ran both of those camshafts, plus a few others, and each has it's place.
What's the purpose of this vehicle?
Occasionally driven on the street, but primarily used for track day events on road courses (Thunderhill, Sonoma Raceway)
Track/daily driver/weekend toy/ miles per year?
Gearing?
rear ends is stock 3.42 with torsion diff
Compression [static]
The Compression calculator with all of the components that i will be using comes out to 11:3:1, not sure if this is correct due to mixed info im getting with regards to cc's of the heads. I used 54cc in my calculation which i pulled from the grandsportregistry site
Plan on running stock heads for how long?
May just get the heads ported during the rebuild process. If I was to do this i've been wanting to get some done my LE. LE1's should get me where I want to be N/A, otherwise I will most likely run the stock heads for about a year.
A concern that just came up was the retainer to guide clearance under lift. Looking at the new springs and retainers they are much shorter than stock at the top to provide extra clearance and the springs are taller. The bottom retainers on the other hand do not look like a direct match for the springs. not comfortable installing these at all.
Please return/throw out the 918 Beehives or start saving for another motor.
Which springs would you recommend other that these?
What's the purpose of this vehicle?
Occasionally driven on the street, but primarily used for track day events on road courses (Thunderhill, Sonoma Raceway)
Track/daily driver/weekend toy/ miles per year?
Gearing?
rear ends is stock 3.42 with torsion diff
Compression [static]
The Compression calculator with all of the components that i will be using comes out to 11:3:1, not sure if this is correct due to mixed info im getting with regards to cc's of the heads. I used 54cc in my calculation which i pulled from the grandsportregistry site
Plan on running stock heads for how long?
May just get the heads ported during the rebuild process. If I was to do this i've been wanting to get some done my LE. LE1's should get me where I want to be N/A, otherwise I will most likely run the stock heads for about a year.
A concern that just came up was the retainer to guide clearance under lift. Looking at the new springs and retainers they are much shorter than stock at the top to provide extra clearance and the springs are taller. The bottom retainers on the other hand do not look like a direct match for the springs. not comfortable installing these at all.
Please return/throw out the 918 Beehives or start saving for another motor.
Which springs would you recommend other that these?
#13
Re: I've read & researched the cam threads...503 or 306...
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.
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.
#14
Re: I've read & researched the cam threads...503 or 306...
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.
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,
#15
Re: I've read & researched the cam threads...503 or 306...
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.
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.