Intake manifold, 350 GM

[rickasbury]

My intake manifold may need to be replaced. We have a rinker 270 with a 350 mpi, 2006.
The boat has a dingy package which means underneath the rear bow seating, the bottom of the compartment is molded to accept the dingy motor for storage- rinker vented the compartment over the 350 motor so water was constantly sitting on the back end of the intake, right where the rotor goes through the block. At some point I will have to replace it. Sooner the better..on the rinker forum someone just replaced theirs, best deal he found was 1200 bucks. Why would this not be a standard gm intake, what would be "marine" on an intake manifold? I went through this when I had to replace the power steering pump. The reservoir is
Merc, but the pump itself is a Saginaw pump for 45 bucks- I think the merc with the reservoir was over 500. Thoughts?

 

[Bt Doctur]

redirect the drains around the motor to preserve it. No one ever said boat engineers were the sharpest knife in the draw
a shame because I have a TBI v8 manifold

 

[rickasbury]

redirect the drains around the motor to preserve it. No one ever said boat engineers were the sharpest knife in the draw
a shame because I have a TBI v8 manifold

My thought process is this is a 350 GM motor adapted for marine. Mine is closed cooling which is even more like a land
based motor. Maybe bearings are more HD, or maybe it's just a modified marine application. I'm going to do more digging, I will put my buddy Chat on it and see what worm holes I find. If they are the same I'm sure I could find a used one for a couple hundred vs 1200!

 

[Lou C]

Is it MPI or a carb? Carb cast iron Vortec intakes can be bought new for a lot less than 1200!
If all it has is external rust just wire brush it, clean with acetone and coat with rust converter and then paint. The cast iron is very thick & not likely to rust thru.

 

[rickasbury]

Looks like a big no way but I thought it was worth a look.

 

[rickasbury]

Is it MPI or a carb? Carb cast iron Vortec intakes can be bought new for a lot less than 1200!
If all it has is external rust just wire brush it, clean with acetone and coat with rust converter and then paint. The cast iron is very thick & not likely to rust thru.

That's good news- I need to get back to tge boat and address this for sure.we are mpi 2006.

 

[Lou C]

Pick up one they are heavy cast iron. Mine has had salt water running inside it (raw water cooling) for at least 25 years and it hasn’t rusted through yet!!!

 

[Bondo]

My intake manifold may need to be replaced. We have a rinker 270 with a 350 mpi, 2006.
The boat has a dingy package which means underneath the rear bow seating, the bottom of the compartment is molded to accept the dingy motor for storage- rinker vented the compartment over the 350 motor so water was constantly sitting on the back end of the intake, right where the rotor goes through the block. At some point I will have to replace it. Sooner the better..on the rinker forum someone just replaced theirs, best deal he found was 1200 bucks. Why would this not be a standard gm intake, what would be "marine" on an intake manifold? I went through this when I had to replace the power steering pump. The reservoir is
Merc, but the pump itself is a Saginaw pump for 45 bucks- I think the merc with the reservoir was over 500. Thoughts?

Ayuh,..... You, 'n yer boat will be better served by redesigning the storage locker the O/B motor sits in, to move the water drips directly to the bilge, so it doesn't drip onto the main engine,....
Then do as Lou says, 'n repaint the intake manifold,.....
Bein' a Mpi, a new one won't be cheap, 'n I doubt there's anything wrong with the current one,....

 

[Scott06]

My intake manifold may need to be replaced. We have a rinker 270 with a 350 mpi, 2006.
The boat has a dingy package which means underneath the rear bow seating, the bottom of the compartment is molded to accept the dingy motor for storage- rinker vented the compartment over the 350 motor so water was constantly sitting on the back end of the intake, right where the rotor goes through the block. At some point I will have to replace it. Sooner the better..on the rinker forum someone just replaced theirs, best deal he found was 1200 bucks. Why would this not be a standard gm intake, what would be "marine" on an intake manifold? I went through this when I had to replace the power steering pump. The reservoir is
Merc, but the pump itself is a Saginaw pump for 45 bucks- I think the merc with the reservoir was over 500. Thoughts?

not sure if you need only the upper or as others have said may not be rotten yet

https://www.ebay.com/itm/156639899434?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=156639899434&targetid=2450593697471&device=c&mktype=pla&googleloc=9007369&poi=&campaignid=24192622954&mkgroupid=196851590342&rlsatarget=aud-1412318123216:pla-2450593697471&abcId=10813841&merchantid=5086385101&gad_source=1&gad_campaignid=24192622954&gbraid=0AAAAAD_QDh_mfKJw_42Ftx603hMnsitPN&gclid=EAIaIQobChMIvOmEtLjJlwMVltufCR3elxCtEAQYASABEgI8fPD_BwE

complete off a VP which is the same chit

https://www.ebay.com/itm/198630012266?_trkparms=itmf%3D1%26aid%3D1110006%26rkt%3D12%26pid%3D101875%26mech%3D1%26algv%3DSimVIDwebV4WithContextualRankerV42_18SignInOut%26pmt%3D1%26amclksrc%3DITM%26sd%3D156639899434%26sid%3DAQALAAAAEPpz4fWY1DNd58pFl7UxwoM%3D%26itm%3D198630012266%26noa%3D0%26plcampt%3D0%3A150780735012%26algo%3DHOMESPLICE.SIM%26brand%3DVolvo+Penta%26asc%3D345455%26ao%3D1%26rk%3D4%26mehot%3Dnone%26lsid%3D100%26meid%3Dc09e7c887456497d83657ef988addf12%26pg%3D2332490&_trksid=p2332490.c101875.m1851&itmprp=cksum%3A198630012266c09e7c887456497d83657ef988addf12%7Cenc%3AAQALAAABIPublsLHMrwa19e7ruMkC3MA1bD5ySgze%252B0f4QBr6mVMH3bgGFjLCZSScvtNoNg5mDjAm05yApoh7QUriUcQgG8dUgwOthB7AkC516OGUdtgHdoVLD1xoDkUR2ywBbGTJnTQ73gpUQ%252FwdK8zEFGrER3UMH6TzX%252BWiKVHwFWPqC4zMOgA4TyKutEMXIT1MzNEVvKhjWzKMyY30LG1VB4KjnrF72DCdAnwEyIQyGmwQjMG%252FeBBat6omOqMD2ZzQSNXXFYaTFRsVQIeYlywTZ2fUBl6irtlBDbt%252FjTPYr%252BvxMJ0%252BreS%252FO2vmYbdahgVfePDIBRYLl%252BE47%252BCKfhOTyXCpGBFs8HJ6GjvODu59OGHgknrEK2co5wqogeZyuhtTK2tgQ%253D%253D%7Campid%3APL_CLK%7Cclp%3A2332490&itmmeta=01M5DG81BFYX6GY143P879KMT1

 

[Scott Danforth]

The MPI intake is expensive.

 

[rickasbury]

not sure if you need only the upper or as others have said may not be rotten yet

https://www.ebay.com/itm/156639899434?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=156639899434&targetid=2450593697471&device=c&mktype=pla&googleloc=9007369&poi=&campaignid=24192622954&mkgroupid=196851590342&rlsatarget=aud-1412318123216:pla-2450593697471&abcId=10813841&merchantid=5086385101&gad_source=1&gad_campaignid=24192622954&gbraid=0AAAAAD_QDh_mfKJw_42Ftx603hMnsitPN&gclid=EAIaIQobChMIvOmEtLjJlwMVltufCR3elxCtEAQYASABEgI8fPD_BwE

complete off a VP which is the same chit

https://www.ebay.com/itm/198630012266?_trkparms=itmf%3D1%26aid%3D1110006%26rkt%3D12%26pid%3D101875%26mech%3D1%26algv%3DSimVIDwebV4WithContextualRankerV42_18SignInOut%26pmt%3D1%26amclksrc%3DITM%26sd%3D156639899434%26sid%3DAQALAAAAEPpz4fWY1DNd58pFl7UxwoM%3D%26itm%3D198630012266%26noa%3D0%26plcampt%3D0%3A150780735012%26algo%3DHOMESPLICE.SIM%26brand%3DVolvo+Penta%26asc%3D345455%26ao%3D1%26rk%3D4%26mehot%3Dnone%26lsid%3D100%26meid%3Dc09e7c887456497d83657ef988addf12%26pg%3D2332490&_trksid=p2332490.c101875.m1851&itmprp=cksum%3A198630012266c09e7c887456497d83657ef988addf12%7Cenc%3AAQALAAABIPublsLHMrwa19e7ruMkC3MA1bD5ySgze%252B0f4QBr6mVMH3bgGFjLCZSScvtNoNg5mDjAm05yApoh7QUriUcQgG8dUgwOthB7AkC516OGUdtgHdoVLD1xoDkUR2ywBbGTJnTQ73gpUQ%252FwdK8zEFGrER3UMH6TzX%252BWiKVHwFWPqC4zMOgA4TyKutEMXIT1MzNEVvKhjWzKMyY30LG1VB4KjnrF72DCdAnwEyIQyGmwQjMG%252FeBBat6omOqMD2ZzQSNXXFYaTFRsVQIeYlywTZ2fUBl6irtlBDbt%252FjTPYr%252BvxMJ0%252BreS%252FO2vmYbdahgVfePDIBRYLl%252BE47%252BCKfhOTyXCpGBFs8HJ6GjvODu59OGHgknrEK2co5wqogeZyuhtTK2tgQ%253D%253D%7Campid%3APL_CLK%7Cclp%3A2332490&itmmeta=01M5DG81BFYX6GY143P879KMT1

If the merc works on an mpi that's a good back up. I would add by recollection, mine did not look like that- the top shape.

 

[rickasbury]

The MPI intake is expensive.

I don't like that! I need to pull the rotor cap and see what I'm working with. I'm happy to be hitting these items before I get back on the water. Did some work on the trailer to the point the axles and brakes I believe to be safe. The coupler to the hitch, surge brakes I have another post running. My chains were way to lite for 10k and that has been corrected...but there is a boat list!

 

[Scott Danforth]

I don't like that!

the used ones are going for nearly the same price on fleabay. however most are rusted around near where the distributor sits.

you could always reach out to some of the marine engine rebuilders.

 

[Scott06]

If the merc works on an mpi that's a good back up. I would add by recollection, mine did not look like that- the top shape.

i could be wrong but it was my recollection that the MPIs for both VP and Merc used a GM intake. Once you get a look at how bad it is and decide if replacement is needed might be worth a call to a place like michigan motorz and see if they have one (they are in MI so fresh water). When I bought my partial engine a few years back they tweaked it with some new take off components (off highperf motors they built) they had in their inventory- like they supplied a OEM fuel set up and TBV ignition vs the aftermarket carter pump and delco est so I could keep my factory harness.

 

[Scott Danforth]

It is a GM intake, just not an automotive one. The GMT 400 trucks used the injection spider arrangement.

The marine intake uses 8 injectors

The lower intake is similar. However I can't find a side by side comparison