Mighty 390 Intake Manifold Question

Hey all! Over the past few months, I have been busy rebuilding the transmission and 390 engine from my '68 F250. I am in the process of putting the engine back together now. I noticed there was a pipe coming out of the intake manifold that was literally corroded down to nothing more than a thin rusted shell of the original pipe that crumbled when I put the vice grips to it.

Has anybody on the site encountered this type of water passage pipe on an intake manifold? The only pipe I can find to come close to it is 1/2" copper pipe to get an OD of ~.680 or so. I don't feel overly comfortable putting copper pipe in an iron intake manifold. Any thoughts on what might work? Iron plumbing pipe is too big. I would appreciate any thoughts on what to use.   

The pipe is under the short peice of hose sticking out of the front of the manifold. (I wish I had the computer skills to circle it).


The rebuilt engine on its way back up.

are you sure its not still available? its press fit right?   if you really hit a dead end i bet you could pipe tap it and then make something that would stay put

Thanks guys! Yes, it was a press fit pipe. No threads. I did get the old pipe out. I did pick up a 3/8" plumbing pipe nipple yesterday at Farm & Fleet to see if it would be close. It was close, but, a bit too large.

Just took a quick measurement of the hole. ~.620 at opening, and goes back to about .575 inside the hole. The pipe threads are around .670-.680 just as you say Pete.

Do you guys have any issues/concerns with pressing copper pipe in? It seems to be the perfect size from an od and id perspective. Just a straight shot. No curves or bends.

Thanks Pete! I will check into reaming it to the right size, then threading for 3/8" pipe. The id on the 3/8" pipe looks a lot smaller than what was in there. Do you think there will be any issues with lower flow...ie...overheating?

i think what he is worried about is the inside diameter of the 3/8 pipe as opposed to the thinner wall steel pipe ,

it looked to be the transfer tube from the water pump to the intake on fords.. if it is the intake heater it probably will never matter

peter1234 wrote: it looked to be the transfer tube from the water pump to the intake on fords.. if it is the intake heater it probably will never matter

Peter....thats exactly what it is.

How about all of you trying Google I might go out on a limb here but I have a feeling that the 390 Ford engine was not designed for marine use but in fact Automotive use in mind 3rd picture says 3/8" NPT. It's called a Intake Water Pump Bypass fitting

Gary S wrote: I have a feeling that the 390 Ford engine was not designed for marine use but in fact Automotive use in mind

Gary,
This is a quiz: What marine engines didn't start off using an automotive or industrial engine?

8122pbrainard wrote:     Gary, This is a quiz: What marine engines didn't start off using an automotive or industrial engine?

I have one of these marine engines in the garage,no automotive or industrial as far as I can tell

I will never forget the 390 Engines with that intake manifold that felt like it weighed 200lbs as you leaned over a hood and tried to install properly without messing up the gaskets. Bad memories. Great running and powerful engines though. Switch to an aluminum intake and save your back. Money well spent.

I bet it will look great all freshened up Dave. Where did you go to get the machine work done? The Merc is a 50 I believe,it's on a very long list to get at least a clean up.

Gary S wrote: 8122pbrainard wrote:     Gary, This is a quiz: What marine engines didn't start off using an automotive or industrial engine? I have one of these marine engines in the garage,no automotive or industrial as far as I can tell

My guess is a 52 or 53'. Isn't it a 10hp looking at that trim ring?

nice Bike..Heritage Classic?


john

I am getting ready to put sealer around the water passages on the intake manifold gasket. Any thoughts as to the best sealant to use?

I just bought a tube of PermaTex Black, but, not sure that is the best. Just wondered what you guys use on your engines?