Need a 1972 318-3 exhaust manifold ASAP

[heynnema]

Sent: 3/13/2005 6:49 PM


I need a passenger side exhaust manifold for my rig. Mine just cracked into two pieces!

Anybody know if a manifold from a 318 passenger engine would fit?

Anybody got a manifold for free/sell/whatever?

HELP!

[chip]

Sent: 3/13/2005 7:24 PM

they can be difficult to find . port size is smaller than the late model 360 manifolds. i found a set on e-bay but, it was some time ago.

[denisondc]

Sent: 3/13/2005 8:31 PM


You can try arizona RV salvage. You could email an inquiry to dartmant67 -at- aol.com; (except type the upper case 2 in place of the -at- and leave no spaces) and see if he can find one among the obsolete-mopar folks. You could search ebay, and when you find someone who has the 413 or 440 motor home manifolds, send them a question, asking if they have the 318-3 manifolds by any chance. One of them is www.1aautomotive.com, who is in the business of new repro parts for obscure applications and offers a lot of mopar exh. manifolds, but no listing specifically for the pre 1975 318-3 engines. They also have a toll free number.I have dealt with other such sellers -- including junkyard owners willing to strip off a part and put it on ebay.

[Slantsixness]

Sent: 3/14/2005 6:36 AM

Al,

the  manifold for a 1968-76 Pickup Truck or Van (small block 318 only) will work, but not for a 360. The 360 has an extra surface area for the 'smog stuff' and the larger passages. None of the car ones will work (unless you use both from a car and the car Y pipe too... but why?! your motor will overheat!)

You can find a manifold from an old van or truck in almost any decently stocked junkyard, and they seem to only go bad in motorhome chassis', so they're likely to be good!

If you have to take one off yourself, be sure to take 11mm and 12mm cheapo ("disposable") sockets because the manifold bolts tend to rust out to about those sizes. tap them on and viola! they'll come off! but the 1/2 and 7/16 regular size bolt heads usually will strip! better safe than sorry! Also take a hacksaw with a couple of blades and cut the y pipe. It'll be easier than trying to undo the y pipe flange bolts!

Save the original "acorn" washers off any used manifold. Using flat washers is what cracks these manifolds, when it's not from heat, and never use the "cement coated/perforated metal" gaskets, they're worthless, but do use gaskets (fel pro and hedman one peice header gaskets work great on the manifolds! sometimes you have to trim them so they don't obstruct the exhaust passages and the manifold...)

If you could wait a week or two, I should have an extra manifold I could ship to you, if it's still good (haven't looked at them in a year....)!

Tom

[denisondc]

Sent: 3/14/2005 3:42 PM

The manifolds with ribs on them might be the -improved- design; made differently to avoid the cracking/warping of the original castings. But I am guessing wildly here.

[Elandan2]

Sent: 3/14/2005 4:38 PM

Another thing to remember is the heat riser.  These engines didn't have a heat riser valve in them, you would have to remove it to prevent any unnecessary back pressure.  Rick

[heynnema]

Sent: 3/14/2005 5:04 PM

Oh, all this great info! Thanks!

After much research, here's what I have...

The passenger-side manifold that cracked, is NOT the original manifold, AND it didn't use all of the special conical washers/bolts to attach it! It also does NOT have a heat riser valve/spring.

Now here's some drama... the Dodge M-300 Parts manual calls out (2) of the casting number 2536477. My driver-side manifold, which DOES have ribs, is casting 2536478!

So, the $64,000 question(s) are:

Is the part number the same for BOTH left and right manifolds?

Should I be looking for a heat riser on the RH manifold, and if not, why not? Doesn't the heat need to go back through the intake manifold to help heat things up?

If the book calls out a 2536477 part, why do I find a 478 part on the LH side?

All these questions...

Thanks for your help guys!

Cheers, Al

[chip]

Sent: 3/14/2005 8:28 PM

i think you will be fine as long as the port sizes match up between the heads and the manifolds.

[heynnema]

Sent: 3/14/2005 11:08 PM

Yup, I'm having a dickens of a time finding this manifold. Tom (Slantsixness) thinks he may have one for me.

I'll have to replace this manifold whilst the engine/head are in the RV. Oh joy. Oh what fun! Just when I finished the entire cooling/heating system rebuild, and I thought that I was FINALLY finished with the total restore... and could start to use it! Sheesh.

The conical washers/bolts probably have to come from the junk yard. I was there today, and it seems that all of the 318/360 engines have them, so that won't be a problem.

Gaskets will be fun to locate too...

Keep those ideas on where I can find this manifold coming... please...

Cheers, Al

[LJ-TJ]

http://www.ebay.com/bhp/318-exhaust-manifold   Hm?