302 head exhaust port bulge and a '65 Valiant LH manifold

-

Kern Dog

Build your car to handle.
FABO Gold Member
Joined
May 23, 2010
Messages
9,672
Reaction score
27,705
Location
Granite Bay CA
I sold a '65 Valiant Convertible to a friend of a friend. The new owner is a decent guy but isn't a hardcore car guy like many of us here. He needs a LOT of help to make this car roadworthy.
It sucks for me though....I sold the car because I don't want it at my house anymore. I thought by selling it, I'd be rid of it.
No.
Because I am friends with these guys, I have assumed the role of the "Foreman" on this job.
I bought an '87 904 trans and installed in, put disc brakes and an 8 1/4" axle in place, painted the engine bay and before Christmas, we set the '87 318 in place. They rebuilt the short block but the heads were deemed okay by the machine shop so they were cleaned up and bolted back on.
Anyone here familiar with the heads that have those air injection ports?
318 B.jpg


The one in the picture above is a cracked 360 head with the same design. The flat part of the exhaust port exit extends below the port and incorporates that small passage that injects air into the exhaust stream in stock applications.
The early A chassis is a tight fit for non stock exhaust manifolds. The original manifolds clear just fine. I had stock manifolds to use but noticed that the #7 exhaust port on the manifold wouldn't lay flat to the head because of the extended pad below the port, like in the picture below:

318 B (3).jpg


The fix? Why not take a grinder to the bulge until the manifold clears?

318 A.jpg


Well, THIS happened. I cut into the water jacket. Again, this here is a cracked 360 head that I tested to see how easy it was to cut through to water. The 318 head was on the engine and in the car. I ended up buying a set of 318 heads from my machine shop guy and swapped them last week.
The damaged head and it's sister are the '302 casting though. I don't know much about the small block stuff but I recall that these had the swirl port chambers and a bit higher compression. Today I took the damaged head to a local guy that does welding jobs. He said he thought he could take a 1/4" welding rod and MIG around it until the hole is filled. He sent me this picture of the completed job:

318 C.jpg


While I no longer need these heads for the Valiant build, I couldn't just let these heads go to waste. $100 to fix the head seems like a good deal.
I have a 318 here that needs a full rebuild along with a 360 that has no heads. Does anyone use '302 heads on a 360?
 
You're going to WAY too much trouble. Here is what I do. I tap the air injection holes to 1/4 20 and get 8 1/4 set screws, coat them with red high temp RTV and screw them in. Over and done. Works real good. "Sometimes" you need to drill them to the correct size to tap to 1/4 but a lot of times you can tap them as is.
 
That isn't the problem. The problem is that the extended flat surface below the exhaust ports prevents the early A body exhaust manifold from laying flat against the head. Grinding for clearance results in cutting through into the water jacket.

318 D_LI.jpg


I've done what you suggest though.
There are some later 318/360 manifolds that do fit but the steering coupler is in the way. The fix for that is a smaller Borgeson U-joint coupler. It isn't a perfect fix though....You lose the "plunge" feature that the stock coupler has.
 
Last edited:
I had the same thing happen. I used a bare header flange between the manifold and my replacement head, that spaced it out far enough to clear.
Using the 302s on a 360 will give you a slight bump in compression, but you'll lose flow with the smaller valves and ports. Probably not too drastic on a "stockish" build.
 
That isn't the problem. The problem is that the extended flat surface below the exhaust ports prevents the early A body exhaust manifold from laying flat against the head. Grinding for clearance results in cutting through into the water jacket.

View attachment 1715853661

I've done what you suggest though.
There are some later 318/360 manifolds that do fit but the steering coupler is in the way. The fix for that is a smaller Borgeson U-joint coupler. It isn't a perfect fix though....You lose the "plunge" feature that the stock coupler has.
Ok, now I get it. What do the manifolds look like in the area they make contact? You think they are thick enough to grind on? Sorry for my lack of comprehension.
 
I don't know exactly how thick the manifold is at the point of contact. Maybe taking a little off of each could work?
I do like Professor Fate's idea if I had no other manifolds here to use.
I have a rear dump 318-360 manifold that will work but requires that Borgeson coupler. I was trying to save this guy the $175 though.
 
I don't know exactly how thick the manifold is at the point of contact. Maybe taking a little off of each could work?
I do like Professor Fate's idea if I had no other manifolds here to use.
I have a rear dump 318-360 manifold that will work but requires that Borgeson coupler. I was trying to save this guy the $175 though.
...and now you're gettin yerself into where you didn't wanna be. You're tryin to help too much. I'm kinda doin similar stuff. When I get done with every little project I have here, I'm gonna be done for a long time I think. Maybe for good cept on my stuff. My health is really startin to turn. It sucks.
 
It's tough to say no sometimes. I have a neighbor who used to find all kinds of stuff that needed welding once he knew I didn't mind doing it for him. Once I told him no a couple times, it finally stopped. It just sucks that kindly telling someone no makes the nice person look like the jerk.
 
This damn car.....

IMG_2824.JPG


Such a long and crappy story.
In 2013, the former owner had it in his driveway doing nothing. The guy he had helping him with the car just disappeared. It had been sitting for 4 years.
I offered to help him, saying that I'd do the body and paint for free. He misunderstood, thinking that I offered to take the car to my place and oversee or do everything on the car.
Three years went by as I finished up a couple of my own projects. When it came time to get to work on this one, he started in about engine rebuilding, upholstery, suspension work, etc. It was clear then that he had a far greater expectation of my involvement than I did.
I reiterated my original offer....I'd do the body and paint and deliver it back to him to finish. He admitted that he'd never finish it himself and offered me a deal....$5000 for this car, a '65 Barracuda project that I thought he already gave me (That I already sold) a 75 Power Wagon and a load of parts.
I did well with the deal. The Barracuda sold for $5000 and I made a similar amount from the parts but I still had this Valiant.
I never wanted it. I would have never looked to buy one. If I wanted a convertible, it would be a 67-69 Dart or a 68-70 Satellite.
I seem to do this crap to myself all too often. I like the Mopars and when some newbie shows interest, I make these offers to help. Most of the time, I end up doing almost everything because the other guy is a part time, fair weathered enthusiast.
 
Wow that's quite project for a "not a car" you are gonna have your hands full lol
 
I remember that little car. I think it's cool. We'd worked somethin out on it if we were local.
 
I'd start by using thick (or double) exhaust gaskets on that side to space the manifold out far enough. Some minor grinding on both the head and manifold usually does the trick if a thick gasket doesn't get it done.
 
They decided to go the route of the later 318/360 manifold and the U-joint steering coupler. It will cover the air injection ports and fit the chassis. The exhaust pipes were made to fit these later manifolds because it came out of a 64 Valiant when the guy changed to headers.
 
-
Back
Top