Featured Technical Ospho for headers or best exhaust for early Dart

no, it's a later A body.

 

Yep I might still go the 273 manifold route. I’m stubborn and can’t let a good challenge go. I’m confident I can built a good set of Tri y headers probably heavy ga SS. Down the road I want a fairly stout 318 or 360 not real hard to get 400 hp which will fill my need for speed. At less 3000 lbs and no power accessories it should be fun. My original goal was a roller 360 400- 450 hp but life happened and some of my funny money funds went away. I’m at the point I just want get it on the road and have some fun.
Dan

 

Like Moriarity, said, your not going to feel the difference on a street driven car, because of a difference between the size of the exhaust ports on the different sbm manifolds. Most flow restrictions don't even come into play until you reach the upper rpm range. You just don't see those on the street too much, but even then a short shift to 2nd (at 4G) will solve the problem.

I ran a .030 over 318 through small port 318 heads, that were match ported to the intake, with a 510 lift 294 duration Mopar cam, through a set of 70s era factory exhaust manifolds (class rules), on a 1/2 mile dirt track. It was a bear coming out of the corners, and it flattened out just before entering the next corner. The next year we swapped the 318 heads for a set of 340/360 heads using the same iron manifolds (intake and exhaust), pulled strong until the driver left off the gas pedal.

The exhaust manifolds will not be a performance issue if the exhaust after them is not too restrictive. The small intake ports on the 318 heads become a problem past 4500 rpm.

 

Made up a manifold to fit.
Lots of tacking welds, test fitting, cutting tacking …,, somewhat crude but from my measurements should be less less restrictive than the silver stock manifold. If it works ok I may remove and clean up the welds, or I may buy a 273 manifold but being stubborn I had to make my original idea work.

After messing around with this I believe I could make a really nice log style header/manifold. Down the road I’ll order a a couple stubbed flanges.
Thanks for all the help guys!
Dan

 

Well, did you ever use oxpho on the headers? How'd it turn out?
Ive used Oxpho on many things other than body panels that ive painted

 

No I didn’t a few people said the off gassing when heated would be bad, so I’ll steer clear of using Ospho on the exhaust. I’ve used Ospho on other items with good results.
Dan

 

The above photos show the break down of the steering coupling. There is a rubber seal that probably can’t take anything over 250 degrees it’s packed with grease I have some high temp sticky wheel bearing grease that will handle 450 I believe.
I’m not worried about temp on the steering shaft or the coupling but I’m not sure about how much temperature the steering box can handle 200 to 220 maybe? The steering box is lubed with grease. My question is will the coupling and shaft conduct too much heat to the gear box and possibly cause damage?
One option is to use a 273 manifold as suggested above.
Opinions?
Thanks
Dan

 

I Ospho-ed then painted headers and the paint popped off at the first turns, which was easy to touch up, being on top.
After that I started cooking headers with my torch to cure the Ospho. Plenty fresh air is advised.

 

I would recommend for the long haul to track down a factory driver side manifold. I just went through all this with my 66 Barracuda. Of the header options out there, the only ones currently being offered are from Dougs, Hooker, TTI, and Sanderson. They are all quite expensive and headers on an early A suck more than a Nickle hooker. The Dougs and TTI headers are a slip fit design the fit between the frame rails, they fit but they are very tight. The Sandersons are a shorty header and less expensive but should be easier to get in and get spark plug access too. The Hookers are also a slip fit setup but are partial Fender well headers with half the pipes going inside the frame rail and the other half into the fender well. plus they only have a 2.5 inch collector on them.. Hedman made the best (in my opinion) fender well headers for these, but they are no longer in production. A set of Hookers were on my 66 barracuda when i got it, but i filled the fender well holes and tracked down factory manifolds for it. unless you are putting out 450 HP the stock manifold will be fine and it fits around everything. here is some pics of mine on a 350 horse 360 magnum.

 

Thank you, nice, Very nice car!
I presently waiting for quotes on manifolds and shipping. Prior to building a manifold I looked and looked for some affordable manifolds with no luck. After starting to build a manifold my searches hit upon a couple.
On the positive side I think I could build a really nice shorty header with the experience I gained doing what I did.
In hind sight I saw a set a few months back for 400 I think should’ve, would’ve, could’ve and been up and running by now maybe.
Dan

 

Ordered a manifold today should be here this week about 200 with shipping.
Thanks all I learned a bunch.
Dan

 

Got the new(old) manifold, a little interference with head, a little grinding on the head and manifold. A few try’s (5) before I got 0.018” clearance.
Thank you to all for your input.
Dan

 

Did you go with studs on the ends? They go into water, so bolts tend to leak. Makes removal a bit more fussy, though. Retorque after a few heat cycles, of course.

 

No used bolts but long enough to go into the water jacket, also used Permatex #2 on the threads. I could’ve used studs but would have to install after manifold are installed, not enough room to install manifolds over studs.
Dan

 

If it leaks I’ll install studs, I’ve had good luck with bolts and No2 Permatex before.
Dan