398 Cam Time

Thanks for the information on the solid roller. I was originally thinking about a solid roller but have gone back and forth, I haven't ordered any of the new valve train so it can go either way. I have heard LSM and Mike Jone mentioned on Yellowbullet before though. I figured with the single plane I could run that MSD dummy set up, I also have a Herron Billet piece along with a new GM oil pump drive I bought years back, so options there as well. It's easy when it's other peoples car, hard when it's your own and loosing interest.

Nothing 'magic' about a custom grind cam. The current cam is a solid choice for the compression that's being run. The only other major consideration aside from the duration and LSA is the lift......and whether the lift takes full advantage of the flow capabilities of the heads.

Typically, you want your cam lift to be roughly .005" below the peak flow of the heads......if you're trying to max out on power.

And that's the ONLY reason to go with a custom grind......to get valve lift into to the max flow point of the heads.


BTW.....a 398ci is the same as a 396ci EXCEPT that the cylinder bore is 4.040" for the 398 vs 4.030" for a 396.

KW

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Originally Posted by KWBaraka

Nothing 'magic' about a custom grind cam. The current cam is a solid choice for the compression that's being run. The only other major consideration aside from the duration and LSA is the lift......and whether the lift takes full advantage of the flow capabilities of the heads.

Typically, you want your cam lift to be roughly .005" below the peak flow of the heads......if you're trying to max out on power.

And that's the ONLY reason to go with a custom grind......to get valve lift into to the max flow point of the heads.


BTW.....a 398ci is the same as a 396ci EXCEPT that the cylinder bore is 4.040" for the 398 vs 4.030" for a 396.

KW

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There's no way a cc306 camshaft would perform well trying to support 398 cubes. Try to find an off the shelf camshaft that would allow a 398 cube LT1 to rev over 7k. A custom camshaft will be in order unless AI has some specialty grinds available. They build enough nasty LT1's that they just might have a few grinds that will work.

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And that's the ONLY reason to go with a custom grind......to get valve lift into to the max flow point of the heads

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Huh? Don't tell that to the stock eliminator guys running enormous duration camshafts on cylinder heads that peak at .550" yet their max lift is .447". There are lots of reasons to go custom cam. I needed a small base circle to clear my rotating assembly, no off the shelf cam would clear. A custom cam is not much more than a good aftermarket cam price-wise, maybe $150-$200.

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Originally Posted by joelster

I would go solid roller. With the amount of miles you put on the car a year, you'd have a "check lash once a year and be done with it" setup. You have the LS1 pcm which allows you a ton of rpm, so take advantage of it, and a single plane. Me setup is all custom, but still not a ton of money, but it is bulletproof and streetable.

$575--LSM custom cam- billet, small base circle, 4/7 firing order swap, 256/260 on a 105
$150--Lunati springs 228lb/525lb (nothing crazy at all)
$175-- Trend custom length pushrods, chromoly, full tapered, .080"
$875--Crower maximus lifters, these are overkill, you could get away with an Isky red-zone lifter and save $400, just make sure you get HIPPO


The cam was a lot, but the company was incredibly easy to deal with. They are very familiar with LT1 stuff and know what size dowel pin you'll need and can grind the cam in a week or so. Comp was a joke to deal with. Trend was also another amazing company to deal with. You won't need a monster .125" pushrod unless the pushrod is angled off of the lifter (like a big-block) or you are running some crazy valve spring pressures. LT1's and sbc's are pretty straight unless you have a big cylinder head like an AFR 227 which has offset valves, and you don't get offset lifters or rockers to correct it.

You could save about $100-$150 going with an AI solid roller grind that they have a part number for, and another $400 by going with a different set of lifters. Also, if you get a billet cam you'll need a special gear for the oil pump drive. I ditched the stock drive and went with a dummy distributor that is billet with the correct gear material. It was roughly $125 (off of the top of my head).

I would get something in the 245/255 range with lift .650"ish. It would pull over 7k with 398 cubes and still make great power with 11.5-1 compression. I'm running 11.77-1 and run pump 93. Those heads are just about as small as I would go for a 398 cube engine, but I think they could still work just as they are.

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Trend was a pleasure to deal with for me as well(except for my wallet, but I needed the big PRs since I have a lot more spring pressure and offset rockers). Very nice people to talk with over the phone.

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Originally Posted by KWBaraka

Nothing 'magic' about a custom grind cam. The current cam is a solid choice for the compression that's being run. The only other major consideration aside from the duration and LSA is the lift......and whether the lift takes full advantage of the flow capabilities of the heads.

Typically, you want your cam lift to be roughly .005" below the peak flow of the heads......if you're trying to max out on power.

And that's the ONLY reason to go with a custom grind......to get valve lift into to the max flow point of the heads.


BTW.....a 398ci is the same as a 396ci EXCEPT that the cylinder bore is 4.040" for the 398 vs 4.030" for a 396.

KW

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This is incorrect. Cam lift should be above peak flow of the heads. Valves are not "on/off" trap doors, and speccing cam lift above peak cfm's allows the valve to dwell longer at higher lifts, increasing power. This is especially true with properly ported heads whose CFM's "Plateau" instead of peaking.

I would never even consider a cc306 on a stroker. It is old, lazy lobe technology and vast advancements in cam's and valvetrain's have been made since it was first ground. Just don't cheap out on springs and pushrods like a lot of people do, then blame the cam when things break.

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Originally Posted by joelster

There's no way a cc306 camshaft would perform well trying to support 398 cubes.........

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Of course you're correct.

The OP's dyno numbers of a 306 cam in his 396 (415 HP/368TQ) is complete chicken-crap ;) . Got it.....thanks for clearing that up.

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Originally Posted by joelster

......Try to find an off the shelf camshaft that would allow a 398 cube LT1 to rev over 7k.......

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Why would he need to rev over 7K RPMs to get the performance that he wants? But I will agree that most off-the-shelf cams won't get 7K RPMs and still make power.....but then, most custom cams won't do that, either.....

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Originally Posted by joelster

……..Huh? Don't tell that to the stock eliminator guys running enormous duration camshafts on cylinder heads that peak at .550" yet their max lift is .447”……...

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Your point has nothing to do with what I posted. Just because their valve lift is significantly lower than the max flow lift of the heads doesn’t mean that they can’t make power at a lower lift.

The question is, why do they run valve lift at ~.447”? Maybe valve train stability considerations? Maybe there are lift restrictions? I don’t know that answer…..but I seriously doubt that this is where they have found that they make MAX power.

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Originally Posted by joelster

……There are lots of reasons to go custom cam. I needed a small base circle to clear mu rotating assemble, no way the off the shelf cam would clear......

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And what? You’re saying that a CC306 cam can’t be ordered with a small base circle? Really? You serious? I bet if you called Comp Cams, they’d send you ANY of their grinds with a small base circle.

Don’t know why you’re so defensive regarding custom cams, but whatever. I never stated that custom cams were a bad thing…..just that “there’s nothing magic” about custom cams.

If the OP already has a cam that he likes and has had success with, there’s nothing wrong with sticking with it.

Now…..all that being said, if you’re building/spec’ing an engine from ‘scratch’, the last item to be determined should be the cam…..and that cam should be spec’ed relative to all the other important specs of the engine (compression ratio, head flow, quench, etc). And yes…..THAT would ordinarily mean a custom grind cam.

KW

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Originally Posted by Puck

.......This is incorrect. Cam lift should be above peak flow of the heads. Valves are not "on/off" trap doors, and speccing cam lift above peak cfm's allows the valve to dwell longer at higher lifts, increasing power. This is especially true with properly ported heads whose CFM's "Plateau" instead of peaking……..

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Exactly! But there-in lies the issue…..even well ported heads can have a peak vs plateau. And if your heads do peak, you have no need/benefit going above that peak with your lift.

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Originally Posted by Puck

........I would never even consider a cc306 on a stroker. It is old, lazy lobe technology and vast advancements in cam's and valvetrain's have been made since it was first ground…..

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I agree. There are better off-the-shelf cams than the 306. And custom grinds can produce more power providing that they’re properly spec’ed.

But in regards to the 306 cam…..go back a re-read what I posted about the cam……

And when I stated about the only reason to go custom cam was to get the lift 'right'......I was ONLY referring to the OP and his current situation. The spec's of the 306 are otherwise, at or near what his system would require.

BTW......yes.....as a previous poster stated, a regular base circle 306 may not be appropriate. If the OP's 306 has a regular base circle, this would be another reason to go with a custom grind.....or a small base 306......if he really likes that grind.

KW

We did the CC306 with the current heads and cam because my buddies and I liked that cam from when we were younger, sounded good and you had some strong running cars with it back then. But for the next set up I figure there would be some thing better. If I didn't have the nitrous stuff done to that single plane I would probably sell it and just reuse my 93 intake I already have.

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Originally Posted by KWBaraka

Of course you're correct.

The OP's dyno numbers of a 306 cam in his 396 (415 HP/368TQ) is complete chicken-crap ;) . Got it.....

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He did that on a stock shortblock, not 396 cubes.

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Originally Posted by KWBaraka

Why would he need to rev over 7K RPMs to get the performance that he wants? But I will agree that most off-the-shelf cams won't get 7K RPMsand still make power.....but then, most custom cams won't do that, either.....

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He has the LS1 pcm, a single plane intake, a bulletproof bottom end, and puts 1000 miles a year on it. He might as well have it set on kill, and do it right the first time.

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Originally Posted by KWBaraka

Your point has nothing to do with what I posted. Just because their valve lift is significantly lower than the max flow lift of the heads doesn’t mean that they can’t make power at a lower lift.

The question is, why do they run valve lift at ~.447”? Maybe valve train stability considerations? Maybe there are lift restrictions? I don’t know that answer…..but I seriously doubt that this is where they have found that they make MAX power.

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They have lift restrictions. I was simply using an example of where a custom cam is needed. You said that the only way you need a custom cam is to get the lift .005" near max flow.

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Originally Posted by KWBaraka

And what? You’re saying that a CC306 cam can’t be ordered with a small base circle? Really? You serious? I bet if you called Comp Cams, they’d send you ANY of their grinds with a small base circle.

Don’t know why you’re so defensive regarding custom cams, but whatever. I never stated that custom cams were a bad thing…..just that “there’s nothing magic” about custom cams.

If the OP already has a cam that he likes and has had success with, there’s nothing wrong with sticking with it.

Now…..all that being said, if you’re building/spec’ing an engine from ‘scratch’, the last item to be determined should be the cam…..and that cam should be spec’ed relative to all the other important specs of the engine (compression ratio, head flow, quench, etc). And yes…..THAT would ordinarily mean a custom grind cam.

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Not for nothing, but you post like you are a know-it-all. The sarcasm, and the winky face........leave that crap to LS1tech. A lot of guys in here have been down the same road Neil is on right now. I'm not "so defensive" of custom cams like you say. But I have yet to see an off the shelf camshaft that is suitable for a 398 cube LT1 with a single plane intake. Maybe there's one out there, but I haven't sen it.

As far as Comp cams goes, lol. Try ordering a small base circle cam from them. If they don't have a master core then they can't go and make a cc306 on a small base. They were a total joke when I went to get a cam. I even found a grind in their file that would work for me but it was for a sbc. The nose is different between an sbc and a factory roller cam. So I told them to grind the sbc specs onto an LT1 core, and they said they couldn't do it. 5 emails, and 2 phone calls to clueless techs make me go look somewhere else.

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Originally Posted by joelster

He did that on a stock shortblock, not 396 cubes........

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OK.....so he was successful with that cam in a 350. Does that mean he can't be successful with that cam in a 398ci? You stated: "There's no way a cc306 camshaft would perform well trying to support 398 cubes." I'm gonna have to chaulk that up as an opinion since I've seen otherwise.

So back to my original point.......if he's happy with the cam, he shouldn't feel compelled to swap it out.

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Originally Posted by joelster

........He has the LS1 pcm, a single plane intake, a bulletproof bottom end, and puts 1000 miles a year on it. He might as well have it set on kill, and do it right the first time......

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A 7K RPM engine is doable......but I didn't see it as his stated goal. If I had, I'd have recommended a custom cam.......a SOLID roller custom cam. After all, we are talking about him having it "set on kill, and doing it right the first time".

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Originally Posted by joelster

......They have lift restrictions. I was simply using an example of where a custom cam is needed. You said that the only way you need a custom cam is to get the lift .005" near max flow.......

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Again......that was as it pertained to the OP and his current cam......and what I saw as his current wants.....not to ALL engine builds.

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Originally Posted by joelster

.......As far as Comp cams goes, lol. Try ordering a small base circle cam from them......

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Been there......done that, so I know it can be made to happen.

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Originally Posted by joelster

.......Not for nothing, but you post like you are a know-it-all. The sarcasm, and the winky face........

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And you responded like a know-it-all. Two wrongs don’t make a right......so where does that leave us?

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Originally Posted by joelster

....... But I have yet to see an off the shelf camshaft that is suitable for a 398 cube LT1 with a single plane intake. Maybe there's one out there, but I haven't sen it.......

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Exactly......you posted you opinion based off your experience.......as did I. You posted based off what you have NOT seen.......as if you've seen everything. And no.....I have not seen everything, but I HAVE seen the 306......and several other off-the-shelf cams perform very well in a variety of strokers......

KW

You are so wrong it hurts to read.

Ok let's play your game, please show me all the ridiculously fast 396/398 LT1 cars with a CC306 that you have "seen otherwise..."