Preface: I can only speak from experience with GM gas vehicles, but this should apply generally to Fords, too.

Much of the heat problem with gas pullers is from heat soak after a hot shutdown. This can be somewhat minimized by idling for several minutes before shutdown. Even better is a thermostatically-controlled electric fan mounted closely behind the radiator. Mine senses the heat rise in the upper radiator hose and kicks in shortly after shutdown and runs for 15 minutes or so, until it senses things have cooled off. This air flow keeps the heat from building up in the doghouse. Avoiding heat soak will make your belts and hoses all last longer, too. The electric puller fan also helps in really heavy traffic or slow climbing on hot days, particularly if you switch it on when heating up either the engine or trans is anticipated..


Starter solenoids are notoriously heat-sensitive on Chevys. I have found the Bakelite cap on solenoids already cracked, ready to fall apart if you looked at it wrong. Replace the solenoid with the high heat one, GM 1114458, or 10457024. It includes a shorter return spring, pn 1978281, or 1958679.

The small terminal on the solenoid should have a Belleville spring nut to keep the small connection tight. The start terminal is long and grows when it gets hot, loosening the connection. When it cools down, the stud becomes shorter, and a good connection is restored. The nut is Delco 2030900 and flat washer 131015. Torque to 12 to 17 in lbs.. A Belleville washer is better than a split lock washer because it provides 360 degree pressure rather than in just one spot. If you can’t get the GM Belleville nut/washer, use a toothed lock washer. That stud growing is why Chevvies are notorious for not starting when hot, but OK when cooler.

A heat shield is a good idea, too. GM sells a heat shield for the solenoid, pn 10068600, but I prefer one that also shields the starter as well. After I have it installed and the wiring routed, I add a little more Thermo Tech shielding around the solenoid with their tape to hold it in place.

Install a direct ground cable from battery to a starter mounting bolt. Or at least from the chassis to a starter mount bolt. I like to run a cable from a starter mount bolt to the same bolt where the frame is grounded to the battery, but all RVs are a little different.

If you feel like a new starter, the Chevy mini-starters are smaller, but more powerful, and allow some extra distance from the hot exhaust. There are other good mini-starters out there, but stock GM will be easier to have repaired if you have a failure far from home. The GM mini works fine on the 502s in both our RV and boat. The boat 502 is pretty high compression, with a lot of advance, and the stock GM mini starter does fine.

Be sure the starter mounting bolts are the shouldered GM bolts, not hardware store bolts, which can allow the starter to misalign and bite you later.

Be sure that the threads and nuts match on the large solenoid terminal. Some solenoids have metric threads, which will accept US nuts, but not a good fit.

Pull the end cap and inspect brush length.


The upper radiator hose suffers greatly from heat soak, too. The most common radiator hose failure is where the upper hose meets the thermostat outlet, or just above it. This is where the hose gets the residual heat from a hot engine after shut down when there is no more water or air flow to cool it. Carry a spare. Also, I never shorten a new hose to make a perfect fit, but leave it long so, in the event of failure, I can cut off the failed part at the thermostat end and reconnect to continue the trip. .

How healthy and happy is your water pump bypass hose? They are no fun to change on the road. I use a steel-reinforced hose from West Marine.

Your engine in general and your doghouse in particular will be cooler if you install a splash shield on the right side. This forces air to travel along the length of the engine before it escapes to the wheel well, like the left side. GM finally started installing them on 7/15/93 with vin 321432. PN is 15983041.

The splash shield will improve air flow so the right rear plug wire and nipple doesn't overheat so readily, and will lessen the likelihood of the right exhaust manifold breaking its bolts.

If you don't do the splash shield thing, consider some extra protection for the right rear plug wire and nipple.

Be sure to use the factory heat shields. They not only offer some heat protection, they offer blast protection in the event of a manifold leak.

Vacuum hoses also suffer from heat. NAPA has an orange silicon rubber hose that stands up well. Do not use any rubber fuel line in the engine compartment. BIG fire hazard there. The inline fuel filters are down by the frame rail for a reason.

I hope you do not have any rubber fuel lines under the doghouse. And check the one from the fuel pump to the chassis. I replace mine yearly, along with trans cooler hoses.

Heat resistant plug wires will last longer. The Jacobs with ceramic nipples are good, but pricey. Champion sells ceramic nipple wires a little more reasonably. A silicone rubber spiral wound wire from a reputable company will last a long time. I use Accel 8.8mm wires. Taylor Spiro Pro wires are rated at 600 deg. Taylor Extreme service wires are rated at over twice that. Taylor also sells some nice sleeves that slip over the nipples. Thermo Tech (or other) sleeves at the nipple end will extend the life of any wires. I buy a 3 ft length of 10410 and cut it to 4 1/2 inch or so lengths that slip over the nipples. A double thickness sleeve made of two diameters of sleeves is even better. Firesleeves from an aircraft supply house or Earl's will work, too. I like Thermo Tek sleeves because they use aluminum foil, which reflects heat, as well as fiberglass insulation. Make sure there are no leaks where the exhaust manifold meets the head, as a leak will blow hot gas on the wires and nipples. When removing the plug nipples, be sure to use the proper tool, rather than pulling on the wire itself. A silicon grease inside the nipple will prevent it from sticking when removal is attempted. A little Super Glue between the nipple and the wire helps keep things together.

Check your heat riser to be sure it opens. A stuck closed heat riser can cause extra engine compartment and carb heat.

Get inside the distributor and look for red dust. Be sure the counterweights are free and lubed. Spark advance is important to avoid overheating. Carry a spare module and coil. The high doghouse temps can cause failures. Use only genuine Delco.

Doghouse temps can be lowered by replacing the exhaust manifolds with either Thorley or Bank$ headers. Their construction of steel tubing eliminates the giant heat sink of the cast iron manifolds that contribute greatly to heat soak. Both are good and will increase hill climbing ability and maybe mileage. Both have lifetime warranties. When headers are installed particular attention must be paid to shielding wiring and hoses from any header tubing nearby. I use sheet metal flashing from Home Depot cut to a Thorley design and clamped in position with hose clamps.

Another heat soak issue is a plug in the bottom of the Quadrajet carb. It can secretly leak and cause a fire. Check it.

Some of this may sound like overkill, but the price of overkill is cheap when compared with a Sunday breakdown far from help and parts and your cell phone doesn’t get a signal and several extras from Deliverance have already driven by twice in their pickup.

Bill,
Did you get ceramic coated headers? I'm thinking about putting on a set. Also, did you put the ThermoTec tape around the header tubes? I talked to Banks about buying just a set of stainless steel headers (they call them Torque Tubes) and they quoted me a price of $950 plus shipping-outrageous. I wish Borla would make a stainless steel set for the P-30. Their big block truck headers are about $650. It looks like the Thorley headers are the way to go with a lifetime warranty.

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Hi,Eddie. You've been awful quiet lately.
I have Thorleys and they caution against wrapping. I don't want to lose that lifetime warranty.
You will be very happy with Thorleys. Back in the sixties, several magazine writers said that the Tri-Wye design was superior to equal length tubes, even if their lengths were correct, which I don't think Bank$ are. I have spoken with people who had used both Bank$ and Thorleys, and they thought Thorley was a little better, but had no hard figures.

I got mine from Summit. 303YS. Used ss band type connector sleeves to connect to my existing 2 1/2 inch exh pipes.
Take a stopwatch and climb a hill before you put them on. Then check afterward. Let us know. I put the Thorleys on with a new motor, so my figures are not relevant. I lost my notes on Thorleys on my previous MH, but remember that I could tow up Chiriaco Summit in third at 50-something instead of buzzing up in 2nd at 40 something. If you are interested, I have a test from a fellow who has hard figures on his before and after test.

Bill - did u install them yourself? I not too mechanically inclined - the mind is willing, but body isn't. I checked into a few shops including a large GMC truck dealer and nobody seems willing to take on the task. The major muffler shops say they can't lift the unit. Any ideas? I need it done right ..

Rusty, yes, I put them in myself. Easy. Have you done mech work before? Do you have a co worker, neighbor or relative who can advise you?
Have you checked speed shops? They sell headers, and should be able to recommend an installer. Some even might do it themselves.

The only possible hitch is removing the old manifold bolts without breaking a them. Soak each bolt and AIR fitting for days and days with PB Blaster. Soak the manifold to pipe bolts, too. Buy a flare nut wrench (American made) for the smog fittings. Use a small impact wrench. Many light, sharp hits are less likely to break the bolt than bigger hits or a strong pull. If you do break off a head, you will need an experienced mechanic or welder to continue. An average welder can weld a nut to the sticking out part of the bolt after the manifold is removed, and removal can be attempted again. A good welder can burn out the remaining bolt head with a cutting torch. The worst that can happen is you will have to remove a head to have it electronically burned out. I don't mean to scare you with this, but it CAN happen. I, and several of my friends have done this without any trouble, however. Several times for me. Even my pickup has Thorleys.

A lift is not needed. I did it in my driveway from a creeper. I used a regular bottle jack to lift one side by jacking on the frame rail behind one front wheel. Perhaps you should find a muffler shop with a pit.
Does your coach have dual 2 1/2" exhausts? If so, you just bolt on the Thorleys and reducers. Then cut the existing pipes off so as to have as small a gap as possible, and join them with a band-type clamp. I recommend the pipe cutter that looks like motorcycle chain with a handle, but a hacksaw, hi speed grinder, or a Sawzall will work. If you have a single exhaust, you will need to convert to duals or use a Y pipe. I suspect a single exhaust has a bit more mid range power, while duals have more wide open throttle power, but have seen no tests on it. Chevy/Workhorse seems to go back and forth on this. If you need to be smog legal, you will need the Thorley heat riser, too.

Again, do the hill test and report back to us.

Thanks for the info... I will locate some PB Blaster. Is it better than liqiud wrench? And I'll let my fingers walk thru the yellow pages again. I'll keep you posted. I do have dual exhausts. I've located the thorleys at summit at a reasonable price, so all I need now is warmer weather and a willing friend. thanks again.

Our mechanics at work are provided with free Liquid Wrench and Knocker Loose. They purchase their own PB Blaster for difficult applications. That is sufficient recommendation for me.