177 blower on 350 for jet boat?

[F-BIRD'88]

My 383 combo does not use stock cylinder heads 200 cfm intake flow.


The most powerfull N A boat motors use a tunnel ram bbc or sbc. 500 hp from a 383 is only 1.3 hp / cid..

Thats a "street motor" Its not going yo happen with 200 cfm heads or dart iron eagle heads.

I can get 400 hp from a 383 thru stock marine ex manifolds. You have dry racing headers exhaust. Use it.

[cjperformance]

Yeah i thought that block might be what you need mate !
Hey I have a set of good s/hand sbc Iron RHS 200cc intake, 64cc chamber heads here. 2.07" intake, 1.6" exhaust. Price is good.
What is the lifter problem?

[F-BIRD'88]

The calc program is not the problem. Its the inputs..

[KnightEngines]

RHS 200's - call incoming!

[KnightEngines]

My 383 combo does not use stock cylinder heads 200 cfm intake flow.


The most powerfull N A boat motors use a tunnel ram bbc or sbc. 500 hp from a 383 is only 1.3 hp / cid..

Thats a "street motor" Its not going yo happen with 200 cfm heads or dart iron eagle heads.

I can get 400 hp from a 383 thru stock marine ex manifolds. You have dry racing headers exhaust. Use it.

Neither would that one, but 200cfm is all a 383 at 5000rpm & 105% VE is gonna use.
You'd need 115% VE to make 450-460hp @ 5000rpm from a 383, which is quite doable - on the way to a fair bit more at higher rpm & with a cam that will not work in a jet boat.
She's gotta peak around 5000 & be real strong below that.

I could also get 400hp through water cooled pipes, but I'd need more than 5000rpm to do it & it wouldn't pull from 1500.

[wyrmrider]

it wouldn't pull from 1500
Exactly- never xxx hard to get up on plane to use the 400+ HP at over 5000 rpm

[lada ok]

Pipemax doesn't usually lie.

382.668 Cubic Inches @ 5000 RPM with 105.0 % Volumetric Efficiency PerCent

Required Intake Flow between 188.2 CFM and 198.3 CFM at 28 Inches
Required Exhaust Flow between 130.7 CFM and 146.9 CFM at 28 Inches

600 RPM/Sec Dyno Test Lowest Low Average Best
Peak HorsePower 378.4 394.0 401.8 409.6
Peak Torque Lbs-Ft 440.7 458.8 467.9 477.0

HorsePower per CID 0.989 1.030 1.050 1.070
Torque per Cubic Inch 1.152 1.199 1.223 1.246



There is a good reason why you see blown engines in jet boats, an NA small block just won't cut it.

Us ANZAC'S are obviously F....stupid

" Your calc is wrong. Garbage in ='s garbage out.The n/a 383 combo I outlined will make a lot more than 400 hp. " ... see I told you so
those foreigners will easily double that with the same combo

Your right with a stock cam in N/A form @ 5000, 6.3 lt's @ 55 bhp / lt = 346 hp, ...tidy up the ports and seats and your on 60+ bhp / lt

So roughly 7-8 lbs boost is a PR of 1.5 +/- so your looking at 519 - 567 bhp

8.5 : 1 max, try the STD cam to start with ( poss more o/l to keep the internals cool )
set the blow off valve loose to start with
My ownly real cocern is that you are V likely to rip the transom out of the boat

[KnightEngines]

Going to have to be a SFT cam in this, hyd roller is gonna cost a motza for lifters to suit the ford lifter bores with chev spacing.
Can buy a SFT cam, lifters, springs etc for less than the cost of the hyd roller lifters alone.

Got the blower, condition is a little rough, gotta drop it off to a mate that fixes these things & find out how bad it is & whether we can use the existing snout.

[lada ok]

SFT cam ... is that standard flat tappet

Yip a plain jane no last name F/T just stock valve gear something like 240* - 50* @ 006 " 25% L/D 110-114 C/L
that would eat it ...easy place to start

[cjperformance]

SFT = Solid Flat Tappet

[RevTheory]

Should be good to 6k rpm. Sorry for making you cock your head over

[cjperformance]

Should be good to 6k rpm. Sorry for making you cock your head over

Do you have valve events or dur @.050"?

[wyrmrider]

111 LCA with a blower in a jet boat???

[KnightEngines]

Yeah, nah!

I'm thinking more like 214/224 @ .050" on 113, in on 107 ICL.
Need to think more tho.

[roadrunner]

Do you get to specify the fuel used in this engine KnightEngines? Premium maybe?...running a fuel that has a decent octane rating would make your job easier!