350 Replacement Options

[LiquidC]

I have a 22' Bayliner and my 350 has low compression in 3 of the cylinders. I don't have the exact numbers in front of me, but on the port side of the motor one cylinder was around 35psi, and both of the adjacent cylinders were around 60psi. All other cylinders were good, around 150psi.

I took off the intake and found a hole in it above the 35psi cylinder, looks like it rusted through . I also noticed a crack in the valley of the block. So I assume it's replacement block time, and the intake is obviously junk. Is a crack in the valley repairable with JB Weld or Marine Tex?

I happen to have a '95 Chevy Tahoe with a 350 in it that I was planning on selling, with 165k miles. I could use the motor out of that and part the rest of it out.

So I have a few options:

1) Attempt a repair of the block & get a new manifold
2) Take the motor out of my Tahoe
3) Get a reman'd block from Rapido (or junk yard block??) and build it up with all the parts off the cracked block.

 

[John_S]

Re: 350 Replacement Options

Sounds like the block is trash to me. 165K miles on the tahoe, probably needs rebuild before installing in the boat, so option 3 would be my vote.

Make sure the boat is in good enough condition that moving forward with an engine replacement is worthwile.

 

[LiquidC]

Re: 350 Replacement Options

Thanks John ... Option #3 seems the safest bet for me too, just don't want to pour more money into the boat. The boat will be in good to great condition, I'm finishing up glassing in new support for a new floor. It is a Bayliner though, so it is an "Econo-Boat" ... which makes me hesitant to spend $1500 on a reman'd block. If I don't find a gem for a block at the junk yard, then that's what I'll be doing.

 

[Fishermark]

Re: 350 Replacement Options

...build it up with all the parts off the cracked block.

Whether or buy a reman engine... rebuild the engine from the Tahoe... or buy a brand new crate engine from Chevy (which would be what I would do) - You will want to look long and hard at the parts you are transferring over. Unless your manifolds and risers are new I would suggest replacing them while you are at it. Especially given the condition of the other parts.

 

[LiquidC]

Re: 350 Replacement Options

OK, here's an update ...

I've been looking on every website I could find for reman'd 350's and prices range from $1700 - $3000 (with shipping included).

I actually found a well known Chevy Dealership selling a brand new crate 350 Long Block. The only thing is the guy kept saying that it is an "Old Style" Carbureted motor, 4 Bolt Main 2 Piece rear seal, for $1200. Seems like a good price, and it includes a 3 year warranty from Chevy.

My current block is from the mid-90's, so what are the major differeneces from this new late-80's motor to that one I have now? I need a new intake anyway, what are other considerations?

Thanks for the help!

 

[haulnazz15]

Re: 350 Replacement Options

Well, as long as the rear main seal is the same on both engines it wouldn't matter. I think I would just sell the Tahoe, and take the proceeds from that to buy a reman engine from US Engines/Rapido/etc. You would be able to reuse most of the old components on the reman engine, so there wouldn't be a whole lot of extra cost. Obviously you'd need a new intake/water pump, and I'd seriously inspect the exhaust manifold/risers if they are over a few years old.

 

[picklenjim]

Re: 350 Replacement Options

Your current mid 90's engine would be a 1 piece rear main seal so you would need a flywheel. You would want to change the freeze/core plugs to brass. If it's a truck intended engine than the camshaft profile would probably work otherwise you may need to change the cam. Is you current engine carburated? If not you would have to do a little fuel line work.

 

[Bondo]

Re: 350 Replacement Options

OK, here's an update ...

I've been looking on every website I could find for reman'd 350's and prices range from $1700 - $3000 (with shipping included).

I actually found a well known Chevy Dealership selling a brand new crate 350 Long Block. The only thing is the guy kept saying that it is an "Old Style" Carbureted motor, 4 Bolt Main 2 Piece rear seal, for $1200. Seems like a good price, and it includes a 3 year warranty from Chevy.

My current block is from the mid-90's, so what are the major differeneces from this new late-80's motor to that one I have now? I need a new intake anyway, what are other considerations?

Thanks for the help!

Ayuh,.... Call him back, 'n ask him to price that dress of long block, for Yer Vintage motor....

I Know he can get 'em....

Swappin' backwards, the extra co$t$ of needed parts, will break the deal....

 

[LiquidC]

Re: 350 Replacement Options

OK, I called the parts guy back at the dealership, he said he does have a brand new late 90's Vortec big block in stock for $1900, with a 3yr warranty.

Do you think it's worth the extra $700 for this motor?

I know the Vortec has more HP (30HP more I think), but does it use more fuel?

Thanks guys

 

[Bondo]

Re: 350 Replacement Options

OK, I called the parts guy back at the dealership, he said he does have a brand new late 90's Vortec big block in stock for $1900, with a 3yr warranty.

Do you think it's worth the extra $700 for this motor?

I know the Vortec has more HP (30HP more I think), but does it use more fuel?

Thanks guys

Ayuh,.... It's a Small block, Long block, not a Big block...

Vortec is more Efficient with it's fuel...

 

[LiquidC]

Re: 350 Replacement Options

Ayuh,.... It's a Small block, Long block, not a Big block...

Vortec is more Efficient with it's fuel...

Sounds good ...

Is there a service manual(s) I can follow to build up a new Long Block to a complete motor?

 

[Bondo]

Re: 350 Replacement Options

Sounds good ...

Is there a service manual(s) I can follow to build up a new Big Block to a complete motor?

Ayuh,.... Yer buyin' a Long block small block Chevy,..... NOT a Big block....

A Big Block is the 396/ 427/ 454/ 502 motors...

 

[LiquidC]

Re: 350 Replacement Options

Ayuh,.... Yer buyin' a Long block small block Chevy,..... NOT a Big block....

A Big Block is the 396/ 427/ 454/ 502 motors...

Gotcha ... edited my previous post. How about the service manuals? Does something like that exist?

 

[LiquidC]

Re: 350 Replacement Options

I just spoke to the parts guy again about the Vortec motor. He said that the motors that he has have truck cams, so that would work for my boat. BUT the block does not have the "hole" for a mechanical fuel pump. I'm not sure which "hole" he's referring to.

Is there a marine version of an electric fuel pump that I could use? Similar to truck motors?

 

[haulnazz15]

Re: 350 Replacement Options

I don't think you want to convert to an electric fuel pump. It takes some wiring changes and additional plumbing for the return line to the tank.

 

[MCL]

Re: 350 Replacement Options

Yes there are marine electric pumps.No difference in plumbing.There is the in/out for fuel and a hose that goes to the carb incase the pump fails,so that it doesnt pump the fuel in the bilge causing a fire hazard.The carter fuel pump is probably your best option,it costs like 110 at jegs.You will need to do a bit of wiring and you also need a oil pressure switch.

 

[LiquidC]

Re: 350 Replacement Options

Thanks guys.

Any chance you know where I could look up the wiring changes info?

 

[Bondo]

Re: 350 Replacement Options

Thanks guys.

Any chance you know where I could look up the wiring changes info?

Ayuh,.... What would Help is for you to Look at yer motor,....

Mid-90s don't have a mechanical fuel pump...

Wait a minute,.... What the 'ell Vintage is this bayliner with the bad motor,..?? There's just vague reference to 90s...

 

[LiquidC]

Re: 350 Replacement Options

It's a '94 Bayliner.

I think the motor that came with it was pieced together off some old stuff.

 

[Bondo]

Re: 350 Replacement Options

It's a '94 Bayliner.

I think the motor that came with it was pieced together off some old stuff.

Ayuh,... Then with the Vortec long block, you'll need a new intake manifold, 'n an electric fuel pump, 'n oil pressure switch for it...

If yer motor don't already have the electric fuel pump....

Btw,... That's another reason to study whatever is sittin' in the motorbox, Now....
We're just Guessin' here now, without knowin'...