455 olds cam choices.

[matt1840]

Ive been searching around but cant really find what im looking for. Im in the process of building a 455 olds motor, forged lower end with K heads. The question im after is what is the biggest cam i can run safely and reliably. Im looking to use hydrolic cam/lifters with 1.6 crane roller rockers. I want good performance but at the same time a mean sounding idle which is why i bought the headers. The boat will be used mostly for cruising with the occasional foot to the floor.
Whats the max lift i can use on the olds valvetrain?
any help with this decision would be greatly appreciated.

[SmokinLowriderSS]

Don't knaow aht a 455's valvetrain will take, but for powerband placement, I would not run a duration any higher than 280* seat to seat. I think that's arround 240* @ .050".
Higher duration will push HP up the RPM envelope to where you will not be able to get to it and remove torque from the bottom end.

[matt1840]

ttt
anyone have any usefull info??? anyone try the marine camshafts from cpperformance???

[oldselmn8tr]

Call Engle race cams they have alot of experiance with Old's motors.

[DelawareDave]

http://www.***boat.com/forums/showthread.php?t=103966

[SmokinLowriderSS]

http://www.***boat.com/forums/showthread.php?t=103966
Yep, there are a lot of threads arround here on people's successful Olds builds and even more info in threads on other things.
That one looks to have good info in it. :)

[DelawareDave]

I have the Comp 280 (230@.050) and in my next motor I will probably go with the JM 25-28, or whatever the PN is from Engle. I will be doing some oil mods while it is apart as well.

[matt1840]

ok guys ive decided on a cam... its not to radical but should get the job done and should have a nice idle... only thing i dont like is the rpm range is 2000-6000 i wanted somethin more like 1500-5500 but this will work. if anyone has info on this cam or has installed it holler my way and let me know how you like it.
cam specs.
comp cams #42-231-4
rpm range 2000 to 6000
adv. duration 280 280
dur @.50 230 230
valve lift with 1.6 rocker .490 .490
lobe seperation 110

[SmokinLowriderSS]

Shorter duration would bring that power band down some, but, I do not think you will be disapointed in that cam.
My Chevy is running a similar duration (but a lot more lift) and the throttle response and mid-range driveability is fabulous. The idle is acceptably low (850RPM) and mildly lopey. real easy to drive, and equally enjoyable.

[ck7684]

What type of drive?