Getting the most torque from a 454...on 87 octane
03-12-2008 | 05:58 PM
#12
Registered
Joined: Jun 2006
Posts: 14,914
Likes: 1
From: Lake Conroe, TX.
You and I agree with my head porter, most velocity through the smallest runners to get the most manageable torque in a "marine" application.
I know I might have gotten more, I like to be on the conservative side of things. I was looking at it this way, if I was going to to spend the money on a "Quality" rotating stroker assembly I would be looking at $2000 not the eagle or scat stuff. For that kind of money I would just put a blower on.
I am just doing a quality inexpensive rebuild using my existing Merc 425 rotating assembly-balanced, fully wedged and ported merlin heads, solid roller, and Weiand Stealth intake.(floors welded up and matched to the heads).
Cam is: in ex
Dur. @ .050 252 264
LS 108
Seat Dur. 290 300
Gross Lift .636" .636"
Heads flow to 0.650"
This set up made 1.33HP/CI in a 502 and 1.34HP/CI in a 540 with 9.8:1
I'm hoping for 1.25HP/CI.
I know I might have gotten more, I like to be on the conservative side of things. I was looking at it this way, if I was going to to spend the money on a "Quality" rotating stroker assembly I would be looking at $2000 not the eagle or scat stuff. For that kind of money I would just put a blower on.
I am just doing a quality inexpensive rebuild using my existing Merc 425 rotating assembly-balanced, fully wedged and ported merlin heads, solid roller, and Weiand Stealth intake.(floors welded up and matched to the heads).
Cam is: in ex
Dur. @ .050 252 264
LS 108
Seat Dur. 290 300
Gross Lift .636" .636"
Heads flow to 0.650"
This set up made 1.33HP/CI in a 502 and 1.34HP/CI in a 540 with 9.8:1
I'm hoping for 1.25HP/CI.
You running dry pipes in that boat?
Who spec'd that cam out? Are they a marine guy. Looks a little agresive for a wet set up. It should no doubt make great power, but I would check before I bolted it in.
Good luck
03-12-2008 | 09:46 PM
#13
Registered
Joined: Jan 2003
Posts: 6,021
Likes: 1,522
From: Grand Rapids, MI
Heads flow Int. 377cfm Ex. 268cfm @ 0.650" with wedged Rec. port Merlins around 316cc
And yes, the cam was spec'd by a well known marine head porter and the first question was, "what exhaust do you have?" He use to build engines for A and B class offshore boats. I think he has a couple World and National titles.
Last edited by Rookie; 03-12-2008 at 09:58 PM.
03-12-2008 | 10:33 PM
#14
Registered
Joined: Jun 2006
Posts: 14,914
Likes: 1
From: Lake Conroe, TX.
Yes they are Stainless Marine dry to the tips. (4" out the back of transom)
Heads flow Int. 377cfm Ex. 268cfm @ 0.650" with wedged Rec. port Merlins around 316cc
And yes, the cam was spec'd by a well known marine head porter and the first question was, "what exhaust do you have?" He use to build engines for A and B class offshore boats. I think he has a couple World and National titles.
Heads flow Int. 377cfm Ex. 268cfm @ 0.650" with wedged Rec. port Merlins around 316cc
And yes, the cam was spec'd by a well known marine head porter and the first question was, "what exhaust do you have?" He use to build engines for A and B class offshore boats. I think he has a couple World and National titles.
Post when you get it off the dyno. It should be a monster.
Good luck and congrats
03-13-2008 | 07:44 AM
#16
Registered
Joined: Jan 2003
Posts: 6,021
Likes: 1,522
From: Grand Rapids, MI
On the dynosheets the 502's HP started to taper off around 5800 but still had good power at 6000. I'm assuming my 470's should start to taper off at 6000 and pull power till 6200. I will either prop to 5800 or rev limit at 5800. I think my power will exceed the speed of my drives. From what I hear TRS's hit a wall somewhere around theses speeds.
I run 72 with 850HP now, thats 12HP/MPH. If I'm anywhere near 1200HP that would put me at (1200HP / 12 HP/MPH) = 100MPH. Realistically I'm hoping for 85mph. all my friends run in the 90's now maybe I'll be able to cruise with them.
Patrick, Jeff
9.6:1 what octane should these be run on? I normally run 92
I run 72 with 850HP now, thats 12HP/MPH. If I'm anywhere near 1200HP that would put me at (1200HP / 12 HP/MPH) = 100MPH. Realistically I'm hoping for 85mph. all my friends run in the 90's now maybe I'll be able to cruise with them.
Patrick, Jeff
9.6:1 what octane should these be run on? I normally run 92
06-29-2008 | 01:36 PM
#18
Registered
Joined: Jan 2003
Posts: 6,021
Likes: 1,522
From: Grand Rapids, MI
Yes
I had a nice flat torque curve and the power wasn't really falling off to fast either. I didn't want to spin it any more on the Dyno than 6500.
I was told that I am leaving power on the table cause I am running only 750cfm Barry Grant carbs, I would have exceeded the 600HP barrier if I had a larger carb.
560 TQ @ 5250 and 590 HP @ 6250-6500
The 565 that we also dynoed that week made just shy of 800HP naturally aspirated. That was fun to see.
I had a nice flat torque curve and the power wasn't really falling off to fast either. I didn't want to spin it any more on the Dyno than 6500.
I was told that I am leaving power on the table cause I am running only 750cfm Barry Grant carbs, I would have exceeded the 600HP barrier if I had a larger carb.
560 TQ @ 5250 and 590 HP @ 6250-6500
The 565 that we also dynoed that week made just shy of 800HP naturally aspirated. That was fun to see.
Last edited by Rookie; 06-29-2008 at 06:51 PM.
