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-   -   10:1 cr sbc (https://www.offshoreonly.com/forums/general-q/386337-10-1-cr-sbc.html)

SB 09-02-2025 06:22 PM


Originally Posted by compedgemarine (Post 4933943)
dumb question but based on what you say the boat is used for why the need to spend money on an aluminum head 383? if it is going to idle or run 3k most of the time why not just replace it with a vortec head 350 and save the money for fuel.

Skip White parts aren’t the most of money

compedgemarine 09-02-2025 08:16 PM

I know about the Skip White stuff just saying that for a motor that he says is going to run idle to 3k most of its life he could just drop a nice running used package in it and go. seems like a lot of work and money for a motor that will never get used for what it is capable of.

Mariah212 09-02-2025 11:14 PM


Originally Posted by compedgemarine (Post 4933943)
dumb question but based on what you say the boat is used for why the need to spend money on an aluminum head 383? if it is going to idle or run 3k most of the time why not just replace it with a vortec head 350 and save the money for fuel.

Not a dumb question at all...I literally have a set of Wuhan vortec heads on the boat currently...1.94/ 1.5 valves mild port job..They work fine..I would love to use them again...Everyone doing engines wants to do them like a car with 10:1 or 10:5 compression...using forged pistons...I kinda want hypereutectic at like 9.7 ...thx...

Tartilla 09-05-2025 08:28 PM


Originally Posted by Mariah212 (Post 4933959)
Not a dumb question at all...I literally have a set of Wuhan vortec heads on the boat currently...1.94/ 1.5 valves mild port job..They work fine..I would love to use them again...Everyone doing engines wants to do them like a car with 10:1 or 10:5 compression...using forged pistons...I kinda want hypereutectic at like 9.7 ...thx...

Forged pistons in marine for a hard working engine are the safer option vs hyperuetectic. Forged are not that much more the hypers.

Doing a set of aftermarket aluminum heads may seem to be a soljtion on paper, but they should be gone through for marine duty, so your cost benefit vs rebuild mild port cleanup on the Vortecs isn't as substantial.

10:1 for Aluminum with modern chambers and a proper cam with some duration is not an issue. Don't over time the ignition, and don't retard it much either. Retarded engines heat up the exhaust valve, and the heads/manifolds. Makes detonation much more likely.

Make sure you get a good grip of the oil temps.

I ran a 355 SBC at 10:1 with iron RHS Pro-Torker heads. 1.94 Vortec copies. No drama, kept max timing at 30°.

Pushed a 20ft Reinell to 55mph. I think the 670 VS carb and the 202° @ 0.050" FT cam choked out at 5500rpm. Not bad for such a small cam, and 10:1.

SB 09-05-2025 08:53 PM

20ft monterey
5 billion hr 1991 350 mag shortblock
Brodix 180IK heads
comp xfi 218/224 113lsa hyd roller
eddie exhaust manifolds
weiand air strike intake
bg 650 vac sec carb
alpha ss drive
72.8 mph :)

tmmii 09-05-2025 08:57 PM

The Mercruiser 350mpi was 9.4:1 and it was stock gm iron heads. I’ve always been told aluminum is safer a point higher because of the better heat dissipation but take that for what it’s worth.

mountainmadness 09-16-2025 10:08 PM


Originally Posted by SB (Post 4934184)
20ft monterey
5 billion hr 1991 350 mag shortblock
Brodix 180IK heads
comp xfi 218/224 113lsa hyd roller
eddie exhaust manifolds
weiand air strike intake
bg 650 vac sec carb
alpha ss drive
72.8 mph :)

Damn show off

SB 09-17-2025 04:44 AM


Originally Posted by mountainmadness (Post 4934828)
Damn show off

Someone needs to continue show a little sbc love around here. Not many of us left. Sylvan, me, ???????

Glad you stopped in !!!!!
King of n/a sbc alpha boats :)

Pismo10 09-17-2025 07:46 AM

383 seems like a great base to build on.


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