Offshoreonly.com - Bbc 454 build.

Offshoreonly.com (https://www.offshoreonly.com/forums/)

- Do It Yourself, Boating on a Budget (https://www.offshoreonly.com/forums/do-yourself-boating-budget-249/)

- - Bbc 454 build. (https://www.offshoreonly.com/forums/do-yourself-boating-budget/358269-bbc-454-build.html)

Quote:

Originally Posted by Unlimited jd (Post 4760863)

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
https://cimg0.ibsrv.net/gimg/www.off...d3d4b65df9.jpg

felpro 4.66" bore gasket on the head
https://cimg8.ibsrv.net/gimg/www.off...c4c1dd3b48.jpg

same gasket on the block
https://cimg9.ibsrv.net/gimg/www.off...aa5c8b10b2.jpg

Quote:

Originally Posted by underpsi68 (Post 4760844)

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.

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

Quote:

Originally Posted by JaniH (Post 4760804)

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.

Straub cam specs.

lobe lift adv .050" 0.200"
int
0.365" 287 228 146
0.375" 290 230 150

exh
0.354" 296 236 155

ICL=106
ECL=118
lobe=112

What does he charge for a cam with 2 different intake lobes ? And why on a build like this ?

Quote:

Originally Posted by MILD THUNDER (Post 4761381)

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

You mean 400-425hp @prop shaft?

Quote:

Originally Posted by SB (Post 4761448)

What does he charge for a cam with 2 different intake lobes ? And why on a build like this ?

its around 700 dolllars

Quote:

Originally Posted by JaniH (Post 4761455)

You mean 400-425hp @prop shaft?

I mean with accessories and your wet exhaust on a dyno. Not with dry dyno headers, and a pumped up correction factor

Quote:

Originally Posted by JaniH (Post 4761458)

its around 700 dolllars

Is the cam core 8620 ? Cast ? Or ?

Also missed one of my questions. Why did he andy/or you feel worth to go with 2 different intake lobes ?