Cams have arrived

[harbormaster]

While at the machinist yesterday I looked at my parts that had arrived. Here is the cam card that might be of interest to som of you motorheads out there. I would love to hear some feedback on the this particular cam.

[RickR]

That's a mighty big lump stick :)
If it is a roller hydraulic I'd run Comp 929 springs.
If it is a flat tappet be VERY careful with the cam break in.
I hope you plan on running a fairly dry exhaust!

[harbormaster]

Rick, Tell me more. I did not want a wild cam. Is this a wild one?

[Rootsy]

that's a lot of duration at .050 lift... but you have to also remember that the bigger the engine (CID) the more mild the camshaft becomes... the peak HP is going to be well into the 5500+ rpm range though i bet... comp says redline of 6200... :eek:

need to watch the exhaust side with these sticks FOR SURE... you don't want reversion and i have a feeling it is cutting it pretty CLOSE.. and find out what they are going to require to "idle" decently. sucks to get a motor fired only to find out that the combo wants to idle at 1200 rpm to be happy once you put it in gear... makes for hell on sterndrives and shifting components...

http://www.compcams.com/Technical/CurrentCatalog/HTML/172-195.asp

extreme marine hydraulic flats...

[harbormaster]

These will be 502's punched to 509's.
750 holleys
W/hydraulic flat lifters
jacketed tube headers.
Heads will have new valve jobs and some cleanup.

We were also estimating a little over 500hp for output

[BUIZILLA]

Good choice for a 509, but if it was me, I would have had it ground on 114* lobe seperation, installed straight up or at 112* intake centerline. Your gonna need 1.7 roller rockers at that lobe lift to be safe, or long slot rockers and watch the adjustment. The 750 carb is your choke point, way too small.... what intake?

JH :sombrero:

[GG Donzi]

I agree with Buizilla, Comp Cams just loves to grind on 110, for Marine use I would have 114. Just curious what heads and intake? Also I would have a Good Exhaust system! Good Luck.

[harbormaster]

Stock GM aluminum intake.
Stock 502 heads

Should I go with 850's instead?

[BUIZILLA]

HM, a couple Sea Demon 850's would be good starters. If it's a dual plane intake, maybe a couple old 800 vacuum secondary spreadbores would be cool...

[harbormaster]

Should i exchange my cams for a different grind?

[RedDog]

Damn - this thread is just all Greek to me. Glad I know some folks here if I ever need to know....

[MOP]

Will a long set of risers work getting the water to dump further away give him some margin?

[BUIZILLA]

HM, I would keep the cams, install straight up, and exit the water as far downstream as possible. That things gonna make some power...

JH

[RickR]

Scot
What kind of headers (Lightning? CMI?)
How far downstream does the water enter the exhaust?
What is the boat weight?

The stock dual plane intake will help you get a better idle than a single plane would and should work fine up to 5500 RPMs.

I was VERY happy with Holley's 830 CFM race carb on the 18/ 454 (non marine, no choke, annular discharge nozzels, and 4 corner idle)
Around $400. I rigged up J tubes out of copper tubing and epoxied in the vent slots.

I'm running a HP 500 Holley 800 on the 502. Feels like I am running out of carb above 5500.


RULE OF THUMB is 230 on the exhaust for a 454/502 with stock manifolds or exhaust with silent choice.

My hyd roller is 222/230 @110 LC installed at 108 theoretical (111 actual) intake lobe centerline.
With A LOT of :rlol: tuning (single plane intake) I have ended up with a 1100 RPM idle out of gear and 800 in gear.
If my idle drops below 600 when shifting into gear I lose my vacuum and get reversion (kills a couple plugs and makes it a bitch getting out of the marina :banghead: ).

[smoothie]

I've been running my 468 with 235 ex lift @ .050,108 deg lobe centers installed straight up,holley 850 carb,torxer manifold for 3 yrs now,it idles all day long at 600 rpm, 800 out of gear, no problems with reversion,and sounds like a cig but of course I have snail 12" risers,so stretched out that would be 24" before my water exits at the tips :yes: my way of thinking is that running a hotter cam and alum logs give me more ponies than a smaller cam and center rise manifolds :checkered

[JimG205]

:wavey: I am a mild motorhead but very knowlegeable-here's my theory-Why put in too radical a cam that's gonna try and suck in any drop of lake or bay water it can and trash your sizeable $3-$5 K engine investment and /or grind the gears right off your outdrive with whiplash to boot.If I were you Scot,I'd tone it down like these other more experienced guy's are suggesting.Just my $.02.Good Luck.

[Forrest]

:wavey: I am a mild motorhead but very knowlegeable-here's my theory-Why put in too radical a cam that's gonna try and suck in any drop of lake or bay water it can and trash your sizeable $3-$5 K engine investment and /or grind the gears right off your outdrive with whiplash to boot.If I were you Scot,I'd tone it down like these other more experienced guy's are suggesting.Just my $.02.Good Luck.

I agree. Why go to the edge for a couple of extra MPH? Reliability is first in my book.