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Buddyc
04-05-2011, 07:03 PM
On the one hand im looking at a 406 long block to go with a Bravo1 on an 18. or maybe a 350 mag pushing about 325 hp.
Then on the other hand im looking at mild 357 reman Alpha going at 275 and using an Alpha.
I do plan on keeping the boat and I would like to do this once...
Any ideas? Also should I stay away from LT1 motors? and if so why?
Im sure this topic gets beat to death but my head is spinning and need to get on track. Doing new transom now so it will be a fresh start

pipnit
04-05-2011, 07:50 PM
what kind of boat?


don't tell me DONZI :bonk:

Pismo
04-05-2011, 08:02 PM
383 with Bravo. LSX with Bravo but big $$. Avoid the 400 small block, too many problems.

MOP
04-05-2011, 08:02 PM
An 18 is fairly so even with a fair bit of power an Alpha is fine and very cheaply replaced, a Bravo setup is pretty costly I know. For what it cost me to switch to a bravo I could have bought 4-5 new SEI Alpha drives and been 2-3 mph faster.

MOP
04-05-2011, 08:07 PM
383 with Bravo. LSX with Bravo but big $$. Avoid the 400 small block, too many problems.

You will get arguments about the 400 SB we have quite a few out doing very well, the only issue they had was steam pockets when used in trucks. If the steam pockets bother anyone simply add transfer lines to the backs of the heads, don't know of any of our guys resorting to that. Lets see what MadDad has to say he has a warm 406 that I have run with.

maddad
04-05-2011, 08:18 PM
I'd go with the 406. The problems that people talk about mostly come from putting heads on without the steam holes drilled. There's no replacement for displacement. That said, there are a few guys here with 383's that are flying also. What ever you choose, remember they all(SBC's)weigh the same, and an extra 56 c.i. makes a difference you can feel.:yes:

Buddyc
04-05-2011, 08:31 PM
I found a 383 LT1 real close to me. Can get it for $2500 350 30 over. Going to send me a spec sheet so I can see cam specs etc... It has 0 miles onit
Also found a member selling a 406 long block but having a hard time getting hold of him.
Hey Maddad what drive are you running?

http://images.craigslist.org/3k33m53oe5Y15O15S5b4487c5d42e6d1f11c4.jpg

MOP
04-05-2011, 08:35 PM
I found a 383 LT1 real close to me. Can get it for $2500 350 30 over. Going to send me a spec sheet so I can see cam specs etc... It has 0 miles onit
Also found a member selling a 406 long block but having a hard time getting hold of him.
Hey Maddad what drive are you running?

http://images.craigslist.org/3k33m53oe5Y15O15S5b4487c5d42e6d1f11c4.jpg

Make sure it is setup marine! Pistons, bearing material, cam shaft, head gaskets and brass core plugs.

Buddyc
04-05-2011, 08:40 PM
Make sure it is setup marine! Pistons, bearing material, cam shaft, head gaskets and brass core plugs.
Its not...he was going to send me specs and I thought I could have it converted if need be. But what do I know... Im a painter for a living....lol

MOP
04-05-2011, 08:47 PM
It may have decent parts, then it sounds like it would be a good buy. The cam may be an issue but who know, post the specs there are a few up here that know there cams. The core plugs are an easy fix, the only one they do not make a brass one for is the cam valley behind the flywheel. The cam valley plug should be primed and painted well they rust out easy from water sprayed up from the flywheel, the is pretty good oil feed back there which makes for a very messy bilge.

Buddyc
04-05-2011, 08:50 PM
I will post tham as soon as I get them... Thank you so much for your input

The Hedgehog
04-05-2011, 09:12 PM
It may have decent parts, then it sounds like it would be a good buy. The cam may be an issue but who know, post the specs there are a few up here that know there cams. The core plugs are an easy fix, the only one they do not make a brass one for is the cam valley behind the flywheel. The cam valley plug should be primed and painted well they rust out easy from water sprayed up from the flywheel, the is pretty good oil feed back there which makes for a very messy bilge.

+1. Not a bad idea, but be ready to marinize it.

younger
04-05-2011, 09:38 PM
If going to do it once, build a motown or dart 400+ cubes and put a bravo behind it. These aftermarket motors are super tough and make great power. If there is cost concerns, go 383 sbc with bravo and you will have a solid performer with reliability.

Rodger
04-05-2011, 09:54 PM
I built my 406 28 years ago. Has not been disassembled yet. As has already been recommended, I drilled steam holes in the heads also.

SamIam
04-05-2011, 09:58 PM
The Dart SHP block is a great foundation for a 400+ cubic inch sb
Have run many 406's with no problems-bb power, sb size.
Same with 383's.

Buddyc
04-05-2011, 10:26 PM
Here is what he sent me on the specs of the 383 LT1



1996 LT1 383 cu in. stroker engine

Engine Block Cylinder Bore = std +.030

Stroke = std + .250

Eagle Crankshaft

Eagle 5.7 Connecting rods

Keith Black Hyperutetic Pistons 11:1 compression ratio

Custom Grind Camshaft 510 / 520 lift 281 / 287 duration

Comp Cams 1.52 roller rocker arms

GM Roller Lifters

Comp Cams Hardened Push Rods 5/16

Melling Oil Pump & Pick Up

SA Timing Chain & Gear

LT1 Aluminum Heads ( hi-perf casting) with Stage 2 Porting

2.02 / 1.60 Manley stainless steel valves

LT4 Springs, Locks & Retainers and Viton seals

Intake Manifold ported to accept up to 58MM throttle body

Sounding a bit greek to me....:confused:

mrfixxall
04-05-2011, 10:33 PM
406 406 406!!!! all of the heads need to be drilled in the heads on a 400 block,if you dont do it the engine will blow the head gaskets and will discolor the 4 center cylinders..

Buddy..are you sure its a 383?? or a 350 lt1..

Buddyc
04-05-2011, 10:41 PM
406 406 406!!!! all of the heads need to be drilled in the heads on a 400 block,if you dont do it the engine will blow the head gaskets and will discolor the 4 center cylinders..

Buddy..are you sure its a 383?? or a 350 lt1..
Look at th specs. He told me 350 .30 over.
I have been tryin to get hold of the 406 long block that guy on the registry has but not much luck. Going to be doing transom this weekend if all goes well

maddad
04-05-2011, 11:09 PM
[QUOTE=Buddyc;596584]Hey Maddad what drive are you running?/QUOTE]

Volvo 280

osur866
04-06-2011, 01:03 AM
11:1 compression, I'd think that's a bit high for a marine engine, but ...
Think the real question is how fast do ya wanna go? If your not wanting to drop a lot of coin I'd think a 383 325-350 hp with alpha would be a decent set-up if youd be happy with 70, keep the boat in the water, easy on the throttle. If you plan on warming up the engine down the road I'd say go with the Bravo drive. Either package I'd strongly suggest you set aside $$ in your budget for a hydraulic steering system, if nothing else at least a single ram add on to keep it safe, you will thank me later at the higher speeds if you plan on running upper 60's into the 70's.

Steve

mrfixxall
04-06-2011, 01:19 AM
Here is what he sent me on the specs of the 383 LT1


1996 LT1 – 383 cu in. stroker engine

Engine Block Cylinder Bore = std +.030”

Stroke = std + .250”

Eagle Crankshaft

Eagle 5.7” Connecting rods

Keith Black Hyperutetic Pistons 11:1 compression ratio

Custom Grind Camshaft 510 / 520 lift 281 / 287 duration

Comp Cams 1.52 roller rocker arms

GM Roller Lifters

Comp Cams Hardened Push Rods 5/16”

Melling Oil Pump & Pick Up

SA Timing Chain & Gear

LT1 Aluminum Heads ( hi-perf casting) with Stage 2 Porting

2.02” / 1.60” Manley stainless steel valves

LT4 Springs, Locks & Retainers and Viton seals

Intake Manifold ported to accept up to 58MM throttle body

Sounding a bit greek to me....:confused:





cam seems mild compared to the lt4 cam..when we spoke that engine has the optispark and it may not be friendly in a marine application.. you are also going to need a tunable pcm and wire harness..you could do away with the optispark and run everything on a crank trigger set up and the easiest tunable pcm and harness would be the Holley dominator set up,it will have all the software to tune the engine to the correct map..

MOP
04-06-2011, 06:26 AM
Sell the injection put a nice "simple" carb setup on it!

Buddyc
04-06-2011, 07:55 AM
11:1 compression, I'd think that's a bit high for a marine engine, but ...
Think the real question is how fast do ya wanna go? If your not wanting to drop a lot of coin I'd think a 383 325-350 hp with alpha would be a decent set-up if youd be happy with 70, keep the boat in the water, easy on the throttle. If you plan on warming up the engine down the road I'd say go with the Bravo drive. Either package I'd strongly suggest you set aside $$ in your budget for a hydraulic steering system, if nothing else at least a single ram add on to keep it safe, you will thank me later at the higher speeds if you plan on running upper 60's into the 70's.

Steve
Isnt 300 hp Max for Alphas?

CHACHI
04-06-2011, 08:34 AM
If you drive 'em hard, 250 is too much for Alphas.

Some numbers run into the 400 range for an Alpha.

It is all in how you drive it and the weight of the boat.

Ken

mrfixxall
04-06-2011, 10:02 AM
Isnt 300 hp Max for Alphas?


back in 87 merc put 330 hp big blocks in front of them..

Buddyc
04-06-2011, 11:47 AM
I won't be beating on it, 70 mph is all the speed I need in her for now.. can an alpha get me theret in say a 350 cu, 300-325 HP? And most importantly still be dependable ?

maddad
04-06-2011, 12:01 PM
:rofl::rofl::rofl::lol9::lol9::lol9:

I won't be beating on it, 70 mph is all the speed I need in her for now..
You can save a bunch of time and money by overpowering it now. Believe me.

Buddyc
04-06-2011, 12:09 PM
:rofl::rofl::rofl::lol9::lol9::lol9:
You can save a bunch of time and money by overpowering it now. Believe me.
I know i must sound pretty dumb by now ... so is a bravo and 383-406 should be in my future ? I just want to start locating stuff and have a plan I can build on...

Walt. H.
04-06-2011, 12:46 PM
You did say it's going into a 18-C, so staying or going with a Alpha is fine due to your 18 being a light hull.
Plus it takes less h/p to turn a Alpha verses the heavier Bravo with more drag surface area because its larger than a Alpha, which also means more speed with the Alpha because its lighter and take less h/p to spin it.

Also the money you save can be used for your engine build and buying other items.
As crazy as it may sound there are some 17 to 19 ft perf boats running over 550 h/p thru a Alpha s/s drive and some even getting a NOS boost and staying together.
But of course having a Bravo hanging off the stern of a 18-C sure does look tougher and on a 18 should be just about bullet proof, so either choice you make you'll do OK.
WH

maddad
04-06-2011, 01:17 PM
I know i must sound pretty dumb by now ... so is a bravo and 383-406 should be in my future ? I just want to start locating stuff and have a plan I can build on...
Not dumb at all. You just get used to what you have fast, and then want more.

mrfixxall
04-06-2011, 01:32 PM
I know i must sound pretty dumb by now ... so is a bravo and 383-406 should be in my future ? I just want to start locating stuff and have a plan I can build on...


Buddy,its a sickness...You will go 70,then more add on's then 75,add a blower go 85,,it will never stop....save a ton of money and do the bigger cibic inch and bravo drive now and it will save you allot more money down the road..

A 383 with 320 hp and a bravo with a 23p prop will give you 70 72 mph.

yeller
04-06-2011, 03:07 PM
I put a 94 LT1 in my 16C and it was a fantastic motor. I can't say enough about the performance of those motors. The problem comes when/if you need to rebuild it. Parts are expensive. It's cheaper to rebuild a BB than the LT1. $2500 sounds like a great deal considering the parts that are in it. I wouldn't worry about the 11:1 compression. They come stock with 10:1. I was able to run 87 octane with the iron head version. The aluminum heads will dissipate heat faster and allow for the higher compression.
The LT1's are "reverse flow" motors. I.e: the water flows through the heads first, then through the block. This allows for better heat dissipation and why they can run the higher compression.
Still...I would run a higher octane at 11:1.

Buddyc
04-06-2011, 04:31 PM
Great info guys. I am going to stick with the Bravo1 for sure. The boat is strong enough and the 383 or 406 would be a great choice I think.'
As far as the LT4 goes, If I go that route, would it be best and more simple to just scrap the EFI and go carborated?

osur866
04-06-2011, 04:45 PM
Not dumb at all. You just get used to what you have fast, and then want more.
Yep ;

yeller
04-06-2011, 07:40 PM
As far as the LT4 goes, If I go that route, would it be best and more simple to just scrap the EFI and go carborated?

That's what I did. I prefer EFI, but it came down to a matter of cost. Cheaper to put on a carb on it than try to get the stock EFI working in a boat.

BTW: GM Performance is the only place you can get a carb intake for the Lt1/Lt4. At least that was the case when I did it 6yrs ago.

Buddyc
04-06-2011, 09:59 PM
That's what I did. I prefer EFI, but it came down to a matter of cost. Cheaper to put on a carb on it than try to get the stock EFI working in a boat.

BTW: GM Performance is the only place you can get a carb intake for the Lt1/Lt4. At least that was the case when I did it 6yrs ago.
Thats good to know, Thank you.
I spoke with Rootsy today and he also likes the idea of a big HP motor going in the Mistress. He beefed up the stringers and should be stronger than stock for sure.
Cant wait to get started.