Exhaust Leak

I did a Google search for Banks Powerpack (banks powerpack ford 460 class c). I got a direct hit on a kit that fits my '94 Class C. I called them to ask about the kit - they told me they don't make a kit to fit my Class C. I tell the guy, "I'm looking at the kit on your web page". The guy got irritated with me for telling him I'm looking at a product on his web site that he says doesn't exist. So I guess a Banks Powerpack is not an option. I don't want to spend that kind of money on a '94 model RV anyway.

From what I've read I'm pretty sure I don't want to go back with a stock manifold. I've searched around and found people recommending Doug Thorley Tri-Y headers (part #514Y-FI3). Does anyone have any experience with these headers? Is there another brand you'd recommend?

I just replaced my manifolds with headers. The passenger side has a broken bolt in the head (at the front) that I couldn't get out. I put it all back together with fiber gaskets and high temp. silicone to fill the gap, hoping that things will stay together while I figure things out.

Heat really is an issue. My solution was to use some Thermo Tec header blankets. They are AWESOME!!!! You should wrap the headers before you install, though. Just do a real close wrap and tie off with stainless steel zip ties or with some stainless wire.

I also started replacing the rest of the rusted out exhaust. So far, I have just gotten the h-pipe replaced and will change out the mufflers when things get a little sunnier in late spring or early summer.

I am assuming you don't have smog testing concerns there in Texas, or do you?

Jose

We didn't have any bolts (technically "capscrews") or studs broken off. I think what actually happened on ours was that the thin stamped steel gaskets rusted through. Probably because they were scraping back and forth with expansion and contraction of the heads and manifolds. Then once it started to leak it leaked more, ate up more gasket, exposed the manifold to warping. That said, the 460 (and the 454 Chevy) both do it. The fact that it's in a van "nose" adds to the problem because heat is trapped. My repair was manifold work as described above, followed by replacing the 2-1/2" exhaust system with a full flow 3" system. That difference is not simply "half an inch" because it's a Pi*R-square" calculation. The larger diameter plus a better muffler and mandrel bent tubing (no wrinkles in bends) made a huge difference in power. Again, not so much in mileage. It also helped the engine run cooler. Had no further trouble with manifold leaks. So the original Manifolds and Crossover Pipe stayed in play. The 1983 was not equipped with a Catalytic Converter. The 3" exhaust system was a "cat back" system that I extended forward to where the cat normally is.
EDIT to add: My plan for if/when manifolds cracked or could not be re-surfaced, was Thorley Headers. They have a connector pipe available. I think it came with the set.

Just saying, that was my fix. Pretty common problem on the 460, Broken exhaust manifold studs causing leaks.

Valkyriebush wrote:
Had same issue on my previous RV with a 460. Had Banks installed and there was 3 broken manifold studs. I hear it's common.

Banks? What are Banks?

Had same issue on my previous RV with a 460. Had Banks installed and there was 3 broken manifold studs. I hear it's common.

Common issue.

They've been done with and without gaskets. The idea of No Gaskets was to try and keep Head and Manifold expansion/contraction dimensions together. Using a gasket, at least in theory, insulates Manifold from Head and leads to leaks.

Yes, some have replaced Manifolds with Headers. In theory they make your doghouse hotter. Some have insulated their headers and been happy with them. You need "torque" headers with long tubes (Doug Thorley Tri-Y used to be popular), NOT "Shorty" headers for high RPM HP.

Problem in these repairs is getting the original bolts out. I was blessed to get all 16 out on our 1983 460. I then had the manifolds machined back into flat and reinstalled using stamped steel gaskets with Never-Seez on both surfaces, and new bolts.

On advice from an old mechanic who had a 460 I did NOT torque the manifolds down tight. Only enough to crush the stampings in the steel manifolds so they'd seal. Kent's idea was that the expansions would never be equal so let the parts slide. Make it easy for them to do so.

Our engine used "heat shield" gaskets. They protected the sparkplug boots, and were stamped steel. I don't think the "waffle" versions would hold up in RV use, but both were available.

What I'm told is 460's like to run with headers. The gains seem to be in lower temperatures and more power, not much better mileage. That's probably due to driver's enjoying the extra punch.