Isky vs. Comp

[Dirtvet]

I am replacing the cam and lifters in my 454 and I was hoping to get some advice from some of you cam gurus. The boat is a Spectra 20 with a stock 12JC pump.
I use it for day cruising mostly. before the old cam went flat the boat did 50mph at 4500rpm.
I have spent hours reading about cam selection on theses fourms and have narrowed my choice down to 3.
1) lift 544/547 duration 270/286 range 1600-5800
2) lift 510/510 duration 286/286 range 2500-6500
3) lift 564/567 duration 278/292 range 2000-6200
More data:
stock 454 short block, as far as I know.
heads-oval port 122cc. open chamber #353049
Edelbrock Torker II intake.
Log's for exhaust
800cfm. Holley 4150 mch. secondary, dbl pump
Mallory 50000v. HEI
I am trying to get a little more performance out of it, but don't want to over cam it.
Which one would you choose?
Thanks,

[FASTRAT]

i personnaly like Comp Cams...i have run them in everything from SBC to BBC with great results for my purpose...i would ck into the Comp 280H cam/kit...it is a very good cam & i highly recommend it...i ran it in a 410 c.i. BBC on the street & it worked great for me...there are some peeps on here that run that cam in there 454's with good results...just my .02 cents
fastrat

[Placecraft Dragstar]

BULLET CAM IS ANOTHER REALLY GOOD CAM FOR JET BOATS!!!! :rollside: :rollside:

[SmokinLowriderSS]

I'm running pretty much an Isky 280H but it's a custom ramp grind to DuaneHTP's specs (steeper than norm). He has had a lot of happy peeps with it, and I am one of them.
I was running almost your identical setup last summer (first summer on the rebuild and new cam).
454, 8.5 to 1 or so.
Same heads (those are good heads, and have a LOT of potential too)
same exhaust logs
Isky cam, .565" lift, 280* seat duration, ground 4* advanced so set straight up. Isky Superlifters, Isky 3-piece springs (bought kit setup)
Performer RPM Air Gap manifold
700 CFM 4150 Holley
12-JF pump, pro-loader, Berk "A" aluminum
Great engine response, from idle to WFO and everywhere in between.
When the engine loosened up by summer's end, 4,800 RPM, 350HP.
This spring turned to Lightning headers and 4" outlets.
5,000 RPM, same impeller cut, 400 HP, and STILL well behaved, till the loud pedal hits the carpet. :boxed:
I'd reccomend my Isky to anyone for a mild to moderate motor.
There are a lot of happy Comp guys on here too. Is this gonna look like a "Ford vs. Chevy" thread in about 10 more posts? :p
Oh, I DID buy a Comp Billet Gears, 9-slot, double-row timing chain setup. I like it too. :)

[PC Rat]

Have you determined why the cam went flat?

[Dirtvet]

I'm not really sure why the cam went flat, but it was most likely my negligence that caused it. The previous owner said the motor had just been rebuilt, and it ran good for the few times I took it out that season. I let it sit for about a year, then started using it again.
I'm thinking it was my lack of maintenance, or the cam was not broke-in when I got it. All but 2 (1st and 2nd lobe) of the cam and lifters look brand new!
I was hoping that by only posting 3 cam options that this thread would not turn into a mudslinging! :argue:
I have to replace it, and was just looking for some advice on maybe getting a little more performance (at a budget price) wile I was at it!

[AzMandella]

I have always been partial to Crower Cams myself.

[flat broke]

Let's all be honest, when it comes to flat tappet cams, it's not like an Isky core is going to be measurably better than a Comp, or a Crower, or vice versa. The name on the box don't mean jack if the profile isn't right for the motor.
I would definitely investigate WHY the cam went bad. Assuming it was broken in (should have been after the first trip) I'd check everything from spring pressure to lifter bore location/allignment. It's not unheard of to see some BBCs with the lifter bores out of whack. If it were me, I'd feel much more comfortable knowing why the last one broke, before I spent the $$ on a new one.
The better way to post this question and get some intellible responses would be to name all the cams A,B,C, etc. And post the spec for each grind. Then folks don't chime in rooting for the brand of stick they have in their ride.
If it's in the budget, a roller setup might be a nice way to help out that relatively low compression motor. Because your compression ratio is low, you can't run too much duration/overlap because you'll bleed off compression that you don't have in abundance to begin with. With a flat tappet setup, you can't run too aggressive of a lobe profile to get lots of lift out of a little duration. A roller setup will allow you to run a higher lift at the same duration when compared to a flat tappet deal, and that should allow for more HP.
Whatever you do, don't select a cam that is going to throw the motor's peak HP waaaay out past you current peak RPM. Assuming that you're running an "A" impeller(which based upon your posted RPM and engine specs you probably are), you aren't going to get much past 5k RPM without doing some major changes to the motor, so don't slap in a cam that makes it's peak power somewhere around 6k or higher.
Good luck,
Chris

[jimthetoolman]

Hey Flatbroke: Should they consider the flow of the heads in the mix?

[cstraub]

More then likely the lifters had insufficient crown resulting in no lifter spin resulting in the lifter peeling the lobes.

[flat broke]

Hey Flatbroke: Should they consider the flow of the heads in the mix?
Uhhh, Yeah...
I'm sure with a little digging you could find some flow numbers for that head on the web. But in the end, it's not like it's going to be a fully optimized situation. The heads are what they are, the compression is what it is, so pick a grind that compliments the power potential of the existing parts, and call it done.
My main point was that the thread was going the route of more "I have an Isky and it kicks ass", or "I have a comp and it runs great" type posts. The focus was on the brand not the grind and ultimately you could pick a winner or loser grind for this application from any mfg.
For that matter, Cstraub who posted right above, could probably provide the gentleman with a very effective cam recommendation that would make good use of his existing parts.
Chris

[disco_charger]

I have a Comp and it runs great. I used to have an Isky and it kicked ass! :rollside:

[Dirtvet]

Chris, thanks for the info,
I diden't want to start a battle of brand loyalties, I guess I should have titled the post different,
Let me re-ask the question.
What grind would best complement the parts that I have listed?
Cam-A; Lift 510/510, Duration 286/286, rpm range 2500-6500
Cam-B; Lift 544/547, Duration 270/286, rpm range 1600-5800
Cam-C; Lift 564/567, Duration 278/292, rpm range 2000-6200
Cam-D; other grind?
Thanks,
-Steve

[Dirtvet]

And oh, BTW I get insufficient crown, :cry: but what does that mean pertaining to lifters?

[SmokinLowriderSS]

Let's all be honest, when it comes to flat tappet cams, it's not like an Isky core is going to be measurably better than a Comp, or a Crower, or vice versa. The name on the box don't mean jack if the profile isn't right for the motor.
I would definitely investigate WHY the cam went bad. Assuming it was broken in (should have been after the first trip) I'd check everything from spring pressure to lifter bore location/allignment. It's not unheard of to see some BBCs with the lifter bores out of whack. If it were me, I'd feel much more comfortable knowing why the last one broke, before I spent the $$ on a new one.
The better way to post this question and get some intellible responses would be to name all the cams A,B,C, etc. And post the spec for each grind. Then folks don't chime in rooting for the brand of stick they have in their ride.
If it's in the budget, a roller setup might be a nice way to help out that relatively low compression motor. Because your compression ratio is low, you can't run too much duration/overlap because you'll bleed off compression that you don't have in abundance to begin with. With a flat tappet setup, you can't run too aggressive of a lobe profile to get lots of lift out of a little duration. A roller setup will allow you to run a higher lift at the same duration when compared to a flat tappet deal, and that should allow for more HP.
Whatever you do, don't select a cam that is going to throw the motor's peak HP waaaay out past you current peak RPM. Assuming that you're running an "A" impeller(which based upon your posted RPM and engine specs you probably are), you aren't going to get much past 5k RPM without doing some major changes to the motor, so don't slap in a cam that makes it's peak power somewhere around 6k or higher.
Good luck,
Chris
You are quite correct Chris,l and tho I did post the brand of cam I have, I was really trying to note his and my engine similarities, and my intent was that the grind I am running is IMO a very good performer, in a situation very close to his.
I don't have anything to compare it to other than the .472"/.480" stock stick it ran for 26 years so I am handicapped there.
Personally, after my recent experience, I would run Cam C, although that long exhaust duration gives me pause. Most of my driving is under 4-grand pulling skiiers/tubes, or cruising, but I want top-end as well. Always a compromise, and I am spinning an A.

[ultra tweaker]

Have you contacted comp for advise? Their tech line is very good. I like cam B because with the mild set up you have you will be making power in a more useable range. I put a comp dual pattern cam in my deal and am very happy. I ran two Schnieders and was also very happy with them also but the comp just seems to run strong

[PC Rat]

How long did it take for the cam to go flat?
Is all the metal from the flattened lobes out of the engine?

[james]

I have a Chevy 468 and I have a Comp Camp 280 High Lift ( 231 at 50). Nothing but good results. If you don't want to over (CAM) just like you said, I would strongly recomend this one.

[RICHARD TILL]

Dirtvet, Think about replacing the springs with your new cam and lifters. Like Placecraft Dragster, i like the bullet cams too. 662-893-5670. talk to John. He`s the owner. Been doing buisness with him for 20 years. No problems at all. I`ll tell you something that i learned the hard way a long time ago. Unless you know that the valve guides have been milled down, i would`nt go over a .550 lift.

[Dirtvet]

Thanks for all of the information that you have provided.
I ordered my cam today. 565 lift 280 duration.
I can't wait to get it running again! Maybe after putting a little BST into it I'll keep it around for a wile. The wife hates it!

[cfm]

A few good threads I started on topic of 'oil vs flat tappet wear"
http://www.speedwake.com/upload/sho...lat+tappet+wear
http://www.speedwake.com/upload/sho...lat+tappet+wear
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Some cam companies offer higher end cores + lifters to also help combat this problem. Unfortunately, some tech line people have no idea if there own company has them or not.
Cstraub or other cam designers should be able to help you out here.
It's a crule world and flat tappets are taking a brunt of it. I'd pony up and go with rollers, unless forced to because of racing rules or such.