350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel ?

[Black as]

Hi guys I have another question when I swapped out my engine from the old 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel Rochester my question is does it need to be re-jetted to suit this engine at this stage the motor is running fine and I checked the plugs and they are a nice tan/ brown colour while running it in or should I do further test by going to WOT and check the colour of the plugs then, any suggestions would be greatly appreciated.

 

[Don S]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Why are you putting a carb on an MPI motor.
Got this from your other post. Note the underlined invoice info.

Its a 5.7 Chev Vortec 330hp HD 4 bolt main, roller cam & lifters
Its a crate engine that came from the US to Australia If that helps

This was on my invoice 5.7 V8 MPi genuine Indmar PCM Crusader Mercruiser engine

If you actually have a carbed engine and not MPI, then you need to lower your WOT rpm down to 44 to 4800 rpm. The higher rpms under load also requires better fuel regulating. Not found in carbs.

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

I put a carb on an MPI motor because you can they sell 8 bolt inlet manifolds to suit Don and why are you getting so annoyed Don you need to relax my friend.

Item number: 251073516754 ON EBAY


And I havent gone to WOT yet as I wanted to know what max rpm should be

 

[Bondo]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Hi guys I have another question when I swapped out my engine from the old 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel Rochester my question is does it need to be re-jetted to suit this engine at this stage the motor is running fine and I checked the plugs and they are a nice tan/ brown colour while running it in or should I do further test by going to WOT and check the colour of the plugs then, any suggestions would be greatly appreciated.

Ayuh,... In theory, the carb probably shouldn't need any jettin' changes, but possibly abit of tunin'...

Just pay attention to the plug colors, 'n adjust accordingly...

The Quadra-jet will easily feed yer motor...

 

[Tail_Gunner]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

I put a carb on an MPI motor because you can they sell 8 bolt inlet manifolds to suit Don and why are you getting so annoyed Don you need to relax my friend.

Item number: 251073516754 ON EBAY


And I havent gone to WOT yet as I wanted to know what max rpm should be

Your old motor apparently did not have vortec head's that would make sense...But if it was tbi yes you can put a tbi on a 4 barrel intake..no emisson's on a boat..

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Curious why it is called an MPI motor when it sounds like you were sold a long block.

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Ayuh,... In theory, the carb probably shouldn't need any jettin' changes, but possibly abit of tunin'...

Just pay attention to the plug colors, 'n adjust accordingly...

The Quadra-jet will easily feed yer motor...

Thanks Bond-o I will do some plug testing this weekend

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Curious why it is called an MPI motor when it sounds like you were sold a long block.

This is all the items I puchased bruceb58

engine 350 Chev Vortec 330hp HD Mercruiser Volvo OMC 4 bolt main, roller cam & lifters
ebay Item number: 380372792585
1 x marine 8 bolt inlet manifold
1 x set of exhaust manifolds
1 x marine water pump
1 x 12" flywheel
1 x SAN JUAN Freshwater Cooling Systems
1 x 5.7L GM Delco Voyager EST marine electronic distributor kit complete with OMC wiring diagram.
1 x CHEV 5.7 litre HARMONIC BALANCER COVER-BLACK x 8" with timing marks

Cost $6700.00

And I must say runs great with a very smooth gear change in and out of gear thanks to the
Delco Voyager EST marine electronic distributor with OMC wiring diagram

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Ah...it IS just a long block. No need for MPI to be mentioned since there is no MPI on it. technically, its not a MPI unless it actually has multi port fuel injection installed on it.

You also are not going to get 330Hp unless it has MPI either but I am sure it is plenty for your boat.

Good idea going with the San Juan system. Its a half system right?

I didn't realize you could get these blocks with manual fuel pump anymore.

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Ah...it IS just a long block. No need for MPI to be mentioned since there is no MPI on it. technically, its not a MPI unless it actually has multi port fuel injection installed on it.

You also are not going to get 330Hp unless it has MPI either but I am sure it is plenty for your boat.

Good idea going with the San Juan system. Its a half system right?

I didn't realize you could get these blocks with manual fuel pump anymore.

My main concern wasn’t the horse power but must say it’s a lot stronger motor than the last one. and a few hundred dollars more gave me a new motor rather than a refurbished one. I went for the half system on the heat exchanger because of space but cant complain as I will just keep an eye on the manifolds, tried to fine stainless manifolds but a little expensive I feel, but I'm keeping my eye out on eBay for some second hand ones. I also didnt bother with manual fuel pump set up as I had an electric set up already in place.

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Yeah, to be a full system, the heat exchanger needs to be a lot bigger because of the extra heat load.

You have your fuel pump wired through an oil pressure switch right?

The Vortec adds another 30 or 40 Hp over a non-Vortec.

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Yeah, to be a full system, the heat exchanger needs to be a lot bigger because of the extra heat load.

You have your fuel pump wired through an oil pressure switch right?

The Vortec adds another 30 or 40 Hp over a non-Vortec.

I'm not really sure bruceb58 as I just connected the fuel lines up, why do you ask?

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

If you have an electric fuel pump without it being wired through an oil pressure switch, the pump will stay on if the engine dies. Not good! You want it to stop. It should only run when you have oil pressure or while cranking.

I just asked because there a re a lot of people that add electric fuel pumps that don't realize this. Your 88 boat didn't come with an electric fuel pump originally so it was added later.

Check out DonS post #4
http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/electric-fuel-pump-534902.html

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

If you have an electric fuel pump without it being wired through an oil pressure switch, the pump will stay on if the engine dies. Not good! You want it to stop. It should only run when you have oil pressure or while cranking.

I just asked because there a re a lot of people that add electric fuel pumps that don't realize this. Your 88 boat didn't come with an electric fuel pump originally so it was added later.

Check out DonS post #4
http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/electric-fuel-pump-534902.html

That’s a good point as when I do turn the motor off and have the ignition on accessories the pump is still going but have made a habit of turning the ignition to the off position. so how do I rewire that bruceb58 from the sender unit or the gauge

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Your gauge uses a sender so you have to tee off that and add a pressure switch as shown in that diagram.

 

[Black as]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Your gauge uses a sender so you have to tee off that and add a pressure switch as shown in that diagram.

No problem that's an easy fix thanks'

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Don't forget the other wire that comes from the starter solenoid that allows the pump to run while cranking. It's also in that diagram.

 

[tazrig]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

I went for the half system on the heat exchanger because of space but cant complain as I will just keep an eye on the manifolds, tried to fine stainless manifolds but a little expensive I feel, but I'm keeping my eye out on eBay for some second hand ones. I also didnt bother with manual fuel pump set up as I had an electric set up already in place.

Don't know if this helps you out or not (or if they would even fit your application) but the new Mercruiser manifolds and elbows have a ceramic coating on the inside of them which greatly reduces rust over the straight old style cast iron ones. Might be a decent compromise between the ones that came with the block and the stainless ones you looked at. Just my 2 cents.

 

[bruceb58]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

Since he has an OMC, that would be a tough modification to make those work.

 

[tazrig]

Re: 350 chev 260hp to the new 5.7 litre vortec engine 330hp we used the same 4 barrel

It's been a while since I've worked on a OMC i/o but isn't a 350 block a 350 block? Or are you talking about modifying from the elbows back?