230lx434

New to the forum but I have a custom built 434 sbc with FAST Xfi fuel injection in a 230lx stingray with B1 outdrive (1.50) with upgrades spinning a tweaked 22p B1 wheel. With that being said the motor was "detuned" if you will in the form a smaller cam. when that took place it shifted the power curve too far down to run where the motor needs and likes to be. On the dyno it nosed over at 5800. I need to pull it up to 6000-6200 to be where i need to be. Motor specs and original and current cam specs below.

Motor:
434 Dart Little M block
Hydraulic roller motor
All forged rotating assembly
Iron RHS 228cc ported heads
69cc chambers
1.6 rockers
Compression 9.94:1
EFI edelbrock single plane manifold also port matched
Current Cam specs 220/224 @.50 .513/.528 @114lsa
Stainless marine SBC manifolds and risers with Corsa diverters to Y and thru hull (always stays through thru hull though)
made 533hp up to 5800

Original Cam:
230/236 @112 lsa
lift was around same as .513/528
made 588hp at 6300

My question is im looking at putting power back into it in terms of camshaft and retune. I am just worried about possible water reversion.
I am going to delete the factory Y and stay solely with Thru Hull but in the process of deleting the diverters (10" of SS tubing to replace) was going to extended the risers where the exhaust and water meet(have a very good fabricator/welder that can extend the water jacket style) that would put the point of intersection at 20" away from top of manifold exit. Also was thinking to help curb reversion putting a 3.5" to 3" reducer on the exhaust pipe to create more of a step that water would have to cross to get back up to motor while being farther away than current setup. Angle to transom is somewhere between 20-25*.

New Cam specs:
I speced this myself and any help on what would work would be great. I am also the one who will be tuning the new setup. I am very familiar with LSX motors but not on marine style engines.

230/236 .518/.530 @113lsa
or
230/234 @113

Trying to keep valve overlap as minimal as possible.

any help, input, suggestions, or experience would be greatly appreciated.

I am not above buying a speced cam from an engine builder that has experience. motor was already built when i bought the boat but verified everything in motor last winter. no problems with reversion with current setup. would like some more bump for my taste but need the extra power back and up 500-600 rpm to get to my goals.

230lx434

Bump for help or to get me pointed toward someone with knowledge on this

mike tkach

iTrader: (3)

bob madera would be the guy to call.585 654 8583

sutphen 30

go w/ the 230/236 on a 114ls

SB

iTrader: (1)

Have a picture of your current exhaust so we can see this "20-25*" angle ?

And yes, a step where the water enters the exhaust is much better than the typical inner being formed (flared out) to the outer with holes drilled for water to enter. Also, slash cut the inner so the top of inner is longer than bottom of inner. Just like slash cut tailpipes are.

SB

iTrader: (1)

Agree. However, my Tim Allen grunt wants to throw a whole lot more cam into it. LOL.

And see if they will give you more lift, assuming the lift #'s given are with 1.6's. 228cc sbc heads are not low lift 'street' heads.

BTW: sounds like a fun hotrod. Congrats !

sutphen 30

ell he only gave me 2 to work w/ so I modded the one that would give him some umph.

MILD THUNDER

iTrader: (3)

I agree. I would fabricate the exhaust to allow me to run a cam the engine wants/deserves. Those are some good heads. Something tells me that combo will love more duration, more lift, and a tighter lobe separation than a 114.

230lx434

thanks guys. I will actually try and get a measurement on it today. I keep it in my warehouse where it has heat since its starting to get cold here now in South Carolina. the 20-25* angle was a guestimate and did not have an eye on it at the time but will go back and try and verify that but may be eating my words on the angle the more i think of it. will try and post a pic also if that will help

230lx434

and i am open to any cam suggestions not just what was posted. don't have a whole lot of experience with marine engines as they seem to be a different breed.