Go Back  Offshoreonly.com > Technical > General Q & A
Anyone ever run this cam in a NA 540 plus build >

Anyone ever run this cam in a NA 540 plus build


Anyone ever run this cam in a NA 540 plus build

Old 08-15-2020, 06:45 PM
Platinum Member
Platinum Member
Thread Starter
iTrader: (7)
getrdunn's Avatar
Join Date: Feb 2009
Location: NW Michigan
Posts: 6,181
Received 22 Likes on 17 Posts
Default Anyone ever run this cam in a NA 540 plus build

565 CI, propping for 6,200-6,300
getrdunn is offline  
Old 08-15-2020, 07:24 PM
Platinum Member
Platinum Member
mcollinstn's Avatar
Join Date: Sep 2001
Location: tn
Posts: 5,631
Received 43 Likes on 29 Posts

Short high rpm blasts in a lightweight screamer? Or prolonged 6300 rpm in a boat that can handle that?

That's a lift number that is going to demand a lot out of your valvesprings and hydraulic lifters. That's why I'm asking how much time you need the motor to sing at the 6200-6300 rpm range.

If you plan on more than 2 minutes at a time at 6,300 you need to spend extra money to lighten your retainers and valves (smaller stems), High strength, lightweight hollow pushrods. You need high quality valvesprings running safely back away from the upper lift limit to prolong life, and you'll want to invest in spring coolers (oil rails, etc). You are far beyond the lift range of dogbone lifters, so you are going to have heavy tiebar hydraulic rollers to contend with. If you run aluminum heads, you need to use GOOD upgraded rocker studs and make certain the bosses are tapped deep enough for a good solid support of the stud flange. Shaft rockers or bolt-down adjustable pedestal rockers are even better.
And, for prolonged 6300 rpm, I'm not sure I would choose hydraulic lifters at the spring pressures you will need. If you must, then I would probably set them up almost fully collapsed (maybe .020 back from metal on metal) or you will inevitably be giving up hp and valvetrain control..

If you're talking about 15 second bursts, then some of the above loses importance.

Marine "endurance" costs a lot.
You will always be best served by running the BEST flowing heads and running a cam that delivers the desired performance while being the easiest on your valvetrain.

I've welded up aluminum BBC heads on many occasions where the stud bosses have been pulled out or broken off of the heads.
Some "raised port" heads don't leave enough meat for the rocker studs because people are resistant to running longer valves. I could go on....
mcollinstn is offline  
The following 2 users liked this post by mcollinstn:
OPS VZLA (08-16-2020), TomZ (08-16-2020)
Old 08-16-2020, 01:04 PM
Join Date: May 2018
Location: Western Pennsylvanoa
Posts: 363
Received 50 Likes on 35 Posts

mcollinstn, what is the max cam lift without spending tons of cash for valve train to survive? AKA building a NA engine that can live for years before refresh?
PA.WOODCHUCK is offline  
Old 08-16-2020, 01:09 PM
Platinum Member
Platinum Member
iTrader: (6)
F-2 Speedy's Avatar
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 7,606
Received 480 Likes on 244 Posts

A lot of the cam choice depends on some other components of the engine
F-2 Speedy is offline  
Old 08-16-2020, 03:12 PM
tripps's Avatar
Join Date: Mar 2001
Location: babylon,NY 11702-4116
Posts: 1,870
Likes: 0
Received 1 Like on 1 Post
Default Cam

Try it I ran one like that in a 598 solid roller iron heads 680 on dyno 15 years ago I need one like that for my 540 in 23 daytona
tripps is offline  
Old 08-16-2020, 09:39 PM
iTrader: (4)
Rookie's Avatar
Join Date: Jan 2003
Location: Grand Rapids, MI
Posts: 4,662
Received 159 Likes on 99 Posts

That 0.400" lobe on 246° IN seems a little steep. I would look into Comps HUC lobes just pick and have them grind.
Attached Files
Rookie is offline  
The following users liked this post:
ICDEDPPL (08-17-2020)
Old 08-16-2020, 10:50 PM
iTrader: (1)
Join Date: Feb 2012
Location: Chesapeake Bay
Posts: 640
Likes: 0
Received 4 Likes on 3 Posts

Originally Posted by getrdunn View Post

565 CI, propping for 6,200-6,300

i ran that exact cam in a 540 ci 10:1 Brodix bb3 335s was a pretty square motor. made peak hp 705 at 6200 . Peak torque was also 700ish (would have to find the sheet for exact number 694 comes to mind) around 5,000. lasted 4 seasons and about 140 hours with a ton of cruising in the 4500-5000 range and would hold it wide open for 10 minutes at a time. Ran flawlessly and At 140ish hours it broke an intake valve spring bending the valve breaking the rocker (stud mounted). When I changed from a 1.50 gear ratio out of curiosity to a 1.65 to see what it would do we were turning 6300 strung out When it let loose. pulled both heads off only that one spring was broken. Refreshed the heads everything checked. New springs lifters rockers 1 new valve and I haven’t gotten a chance with all the bs going on to put it back together.

for what it’s worth I was only able to turn it 5900/6000 in a 24’ V bottom and a good 26p prop. Still ran a respectable 82/83 every day.

mickeymcclgn is offline  
Old 08-17-2020, 09:04 AM
Join Date: Oct 2010
Location: Cheboygan, MI
Posts: 1,228
Received 84 Likes on 62 Posts

I'm running a custom Comp Cams CB-3113/3151 that ends up being .623/.612 lift, 242/252 @ .050" and lobe separation at 112 with a 1.7 rocker. It's in a 524ci BBC with AFR 315 heads Ferrea valves, Isky Tool steel springs, Crower Pro-Magnum rockers with a stud girdle. Don't run much over 5800 as the boat gets pretty squirrelly past 80 in a Velocity 280. It has enough torque to break my labbed 30p loose even after I'm on plane if I nail it hard. I've got 150 hours on it so far and no issues. Definitely makes good power for it's size.
ThisIsLivin is offline  
The following users liked this post:
SB (08-17-2020)
Old 08-17-2020, 10:07 AM
Join Date: Aug 2003
Location: Racine, Wisconsin
Posts: 1,105
Received 13 Likes on 4 Posts

What does Crane say?
kvogt is offline  
Old 08-17-2020, 10:17 AM
Gold Member
Gold Member
Join Date: Jul 2008
Location: Delray Beach, FL
Posts: 3,256
Received 102 Likes on 56 Posts

Interesting cam. I assume you are running dry exhaust?
Keith Atlanta is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.