96 5.7 build - cracked block and cracked heads.

[GoodDwrecktions]

Bought a boat that sat for 10 years and surprise the plugs were left out and the engine was left full of water so it was seized.
I pulled the engine out and tore it down and took the block and heads to the machine shop.
**The intention is to do a stock rebuild... Not create a powerhouse that drinks fuel for an expensive hobby**

The result:
3 holes would need to be sleeved and the block is cracked.
Cylinder heads are cracked and unusable.

So now:
I'm left hunting around for 350 small block chev cores but there's so much variation and no clarity at all on what block and heads my 96 actually has. The idea is to find a core. Get it machined and build this engine.

The question:
What block do I need? What block was this thing actually? (I've found a 87 with two bolt mains out of a pick up the centre intake manifold bolts are angled, Is this what I'm looking for? Or not exactly?)

What heads do I need? Pre vortec... New style or old style. What year range or style was actually on my original engine. I don't want to have to buy a different intake manifold.

Any other advice is of course welcomed.

Engine info (original)

Serial#: 0F608430
Model#457B100JS



Thank You!

Derek

 

[Scott Danforth]

Your 96 most likely has vortec heads (8 bolts on intake).

If so....you need a 1996 to 2000 Chevy or gmc truck motor as your core.

If your motor has 12 intake bolts, it's a 1992-1995 GM truck motor with either 76 or 64cc heads ( post your head casting numbers)

The cost to build a motor is the same whether you build a stock 350 with crappy stock pistons at 280hp , or you build a proper quenched stroker at 380hp. Building a better motor doesn't suck more fuel. In fact, it usually is more efficient at cruise. Its your right hand on the controls that directly affects fuel economy

 

[Rick Stephens]

The key is count the bolts on the intake. 8 or 12, just like Scott said.

Being a SBC you got it made. So many blocks and parts available.

 

[Bt Doctur]

Where are you located?

 

[GoodDwrecktions]

I'm located in Edmonton, Alberta, Canada

The bolt count is 12 **BUT** there is a question of whether or not the middle two bolts are angled the same as the other 4 on each side or if they go straight down. I've been having trouble reaching clarity on this one.

I will get all the casting numbers right away.

 

[Scott Danforth]

there is no BUT. with 12 bolts, you have a 1995 motor PERIOD. (Non vortec)

if you want more power, go with a 1996 or later with vortec heads. if you want to rebuild to what you have, get a 1998 to 1995 (preferably the 1992-1995) core.

 

[GoodDwrecktions]

there is no BUT. with 12 bolts, you have a 1995 motor PERIOD. (Non vortec)

if you want more power, go with a 1996 or later with vortec heads. if you want to rebuild to what you have, get a 1998 to 1995 (preferably the 1992-1995) core.

You wrote 1998 to 1995? Was that a typo?

 

[Scott Danforth]

yes, should have been 1988

here is the breakdown of recent SBC changes (not boat specific)

Late 1985 / early 1986 - change from 2 piece rear crank seal to 1-piece
1986 / early 1987 - change from perimeter bolts to center bolts on valve covers
1988 / early 1989 - change from flat tappet to roller cam
1992 - change from mechanical fuel bosses to electric fuel pumps
1996 - addition of vortec heads, introduction of fixed valve train

in boats, about 1998, they consolidated to the 168 tooth flywheel

if I was looking for an SBC core to build for a boat, I would do the following:

find a 1988-1992 block with the machined fuel pump mount. have the block zero decked and bored to 4.060. I would stuff in a 3.75" stroke SCAT forged crank with D-shaped forged dished pistons about +12cc's and appropriate rods

I would have the whole thing ballanced

I would get a brand new set of vortec heads without springs. install a set of beehive LS springs

I would get a comp cam XM270HR cam

I would install a mehling high volume oil pump

I would get a new aluminum Edelbrock air gap intake, and install a holley 750cfm vacuum secondary marine carb. install #74 primary jets, #100 secondary jets, a #25 power valve, and the second lightest spring available. (or your can install an edelbrock 1409 and play with calibration kits)

I would assemble the whole assembly, install in the boat, set base timing at 12BTDC, fill the tank with 89 octane and go boating every day with a grin on my face.

the forged bottom end would last forever in a boat no mater how hard you beat it. the motor would be capable of 6500 RPM all day long, however you would never use it. it would sip fuel on cruise (compared to a stock 350 build with the 4 piston reliefs in the tops of the pistons), and would provide a smile on your face when you wanted to get up and boogy

 

[Rick Stephens]

If you go Vortec you will be able to swap over all exhaust and electrical components from the original motor. It is a nice update to the engine power going with Vortec. I believe your '96 will an electric fuel pump on it, if not, know that a Vortec engine will not have the place to install a mechanical fuel pump and you will have to install an electric. (Scott said this as well)

You can get lots of help here making it all work.

 

[FreeBeeTony]

Scott Danforth , really like the description of that build. Think an Alpha1 would last behind it?

 

[Scott Danforth]

It would last quite a while if you watch the hole shot and don't get airborne

 

[NHGuy]

I agree with that engine, in fact I just built a slightly better version of it. I would not use a high volume oil pump though. Boat engines turn so much faster than car & truck engines that there's loads of oil volume and pressure.
A stroker requires engine block clearance work. You can do this yourself, but then you will need to reassemble and recheck clearance. It takes time. Or you could pay a machine shop to do the clearance work. Believe me, they know where to grind.
If you don't want to spend the time or money to clearance, you bore and it's a 355 inch with a 3.48" stroke which is standard and can be very quickly & well built.
Beehive springs and good (Scorpion) roller rockers are terrific and very worthwhile upgrades that will pay off in reduced wear, mass, and longevity with either build.
A d dish piston with .040 clearance is imperative for reduced detonation and increased power.
I have this in a 1997 383 with Dart heads and an Eagle cast crank in front of an Alpha.
The boat is a fat 4000 lb Formula F223 LS. It gets brought to plane just as slowly as it planed with the 350 MAG that preceded this engine. to avoid damaging the Alpha gen II drive. I did use some high quality drive lube, Amsoil Severe Gear. It's been perfect so far with 12 hours run time.
I haven't completely finished tuning the carburetion it and has already met my expectations.

Do it, will make you smile. I promise!

 

[GoodDwrecktions]

The Casting Number for the heads is 14096217

Still waiting on the casting number from the block.

They certainly aren't very clear about whether the center bolts are 90 deg or 72 deg.

14096217	Manufacturer: Chevrolet Category: Cylinder Heads Type: Small Block V8 Date: 1955-1986 Notes: 350, [COLOR=#1B8EDE !important]crate[/COLOR] engine, 285hp or 300hp, 64cc [COLOR=#1B8EDE !important]chambers[/COLOR], 72 degree or 90 degree center intake manifold bolt angles

Details

 

[Scott Danforth]

14096217 Iron heads, are centerbolt. They are 1987+ (and later) and feature 72 degree center bolts. Valves are 1.94 and 1.5 with 64cc combustion chambers used on crate motors and marine motors. The head is the same as L98 Iron head 14011083

 

[GoodDwrecktions]

Have finally gotten the casting # for the block

10243880

So? Among a few questions... Main Question is... Does it need to be a vortec block? Or will any 350 block with a mechanical fuel pump mount and one peice rear main do just fine??

Thank you all so much for being so helpful!

 

[NHGuy]

Yes, any 1 piece rear seal block will accept your other parts. Heads, starter, alternator, power steering, mounts.
I'd suggest getting one with a mechanical fuel pump if you can. Keep it simple.
I spent over $100 between a pump, wiring and pressure switches for electric.. It's nice that it keeps up with the fuel demand of the upgraded engine, but it took some thinking and copying to do it a way that was safe and up to Mercruiser standard.

 

[Rick Stephens]

I spent over $100 between a pump, wiring and pressure switches for electric.. It's nice that it keeps up with the fuel demand of the upgraded engine, but it took some thinking and copying to do it a way that was safe and up to Mercruiser standard.

Me too. Although I spent a little more since I went with the OEM Airtex pump. That let me use the OEM Mercruiser fuel pump mount and stainless line between it and my carb. Made for a super neat and stock install, which I like.

 

[NHGuy]

Anyway, OP avoid the electric pump if possible! It's more complicated and more money for the same fuel supply.

 

[anesthes]

y
1988 / early 1989 - change from flat tappet to roller cam
1992 - change from mechanical fuel bosses to electric fuel pumps

Interesting. The motor (350/260hp) I pulled out of an '89 parts boat was a 1pc rms, had roller cam provisions but was flat tappet.

The motor in my '95 bayliner (260hp) has a mechanical fuel pump.

I know everyone says the 217 castings are essentially the same as the fbody L98 head (083) but don't they get sodium filled marine valves?

-- Joe

 

[Scott Danforth]

Marine heads don't get sodium filled valves. If you built them youself maybe. They get the same valves that come on the trucks and other industrial motors. My last build had stainless valves because that is what I paid for.

Remember, the marine motors are a subset of the industrial motors and lag the automotive world by a bit.

Was your 89 motor that had a flat tappet cam a mercruiser or Volvo. Volvo installed their own spec'd cams for a while until their stock was used up.