Bbc 454 build.

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10-09-2020 | 03:52 PM

#191

JaniH

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From: Finland

Quote:

Originally Posted by Unlimited jd

youd be better off selling the short block and buying a clean 330. And bore notching a 509 with those heads is a waste of time. This combo won’t make power past 4200 rpm

first plan was to instal 2.19" intake valves, so we did radical valve unshrounding to the chambers. because the flow was enough to reach my goals even with stock valve size, we did not go with 2.19".

before notching the block

felpro 4.66" bore gasket on the head

same gasket on the block

10-09-2020 | 04:08 PM

#192

JaniH

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From: Finland

Quote:

Originally Posted by underpsi68

What will your cruise speed be at 2000-2500rpm?

for example, pitch 24", 2500rpm, gear ratio 1.5, 28mph with 25% slip. hard to tell my cruising slip but i have bravo 24" and hydromotive p5x 24" for the firts tests. My X-dimension is 17.5". build thread of the hull is found from the restorations & upgrades section, chris craft stinger 260.

Last edited by JaniH; 10-09-2020 at 04:12 PM.

10-12-2020 | 05:55 PM

#193

Baja 250es

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Joined: Sep 2020

Posts: 216

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From: Kentucky

Newbie 454 overhaul

Ok go ahead i have big shoulders i can take the abuse but was looking for help this winter i just pulled my gen 4 ,454, 365 hp, bravo 1 setup out of my boat to rebuild this winter myself and id like to bump up hp a lil just like every guy but I have never built a performance marine engine i have built numerous pick up motors and my mustang im a diesel mechanic by trade so I have the know how just need help with the parts list id like to end up with 450hp - 500hp roughly but I want it reliable it has 700hrs on it runs fine just think it's time lol any help would be awesome thank u

10-12-2020 | 07:39 PM

#194

MILD THUNDER

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Joined: Jul 2004

Posts: 11,332

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From: chicago

Quote:

Originally Posted by JaniH

Final engine specs. feel free to estimate power/torque

-Gm 502,gen6 block, bored 030 over, bores notched.
-Eagle forged crank
-Eagle 6.385 h-beam rods, l19 bolts
-Mahle -13cc dome powerpack forged pistons
-Comp ratio 9.5:1
-Quench: 0.037"
-Gm 360 casting peanut heads,ported, stock size 2,06"/1,72" ferrea stainless steel valves, intake flow with intake manifold, bad 273cfm @ 0.600" lift, good 283cfm @ 0.600" lift, exhaust 202cfm without pipe.
- Weiand street warrior 2123, dual plane intake
-Rochester q-jet 800cfm
-Crane gold 1.7 rockers
-Gm roller lifters
-Comp 930 valve springs
-Cam specs=?, will post the specs later
-Melling select series HV oil pump
-8qt marine oil pan
-merc thunderbolt ignition
-Stainless marine exhaust manifolds, 6" taller risers, vertical part of the riser extended 4" to silent choice diverters.
-Bearing clearances: mains 0.0031"(number 5=0.0039"), rods 0.0029".
-Piston to wall clearance: 0.0065"

400-425 hp in full marine trim on a legitimate dyno. 550-600hp on salesmans dyno. Thats my guess.