Questions and Answers

Which Head To Get? Q. Vince, I have to replace my drivers side cylinder head in my 1990 Ford F-250 (broken where the manifold bolts on at the first port). The truck has a 7.5 liter 460 Fuel injected engine without a smog pump. I contacted many different cylinder head suppliers and the average cost for the head is $350.00 plus a $150.00 core charge (I do not have a core due to the broken head).

So the final cost to me would be $500.00 + shipping, bolt set, gasket, and installation for a grand total of $950.00 plus dollars. One of the suppliers told me they could give me an air injected head, and he has plugs to plug up the ports that are used for the smog pump. He says the cast number is the same (E7TE) and the valves and combustion chambers are the same size on the two heads. He says the combustion of the two heads are equal, so I should not run into the problem with having more combustion on one side over the other.

I have already rebuilt the head on the other side just 2 months ago so I'm not concerned that if the proper head is used, I will have uneven combustion anyways due to wear. The truck only has 90,000 miles on it. He says he can give me the air injected head already rebuilt and plugged for $170.00 and add $125.00 for a core charge. $295.00 total is a lot better than the $500.00 I was looking at. Does this sound right to you? Is it worth the savings to attempt?

The truck is used for household runs to the city dump, the lumber yard for small household projects, and around town trips. It is not used for any commercial work, plowing, or long trips (with a 7.5L 460 any long trips would drain my retirement funds in gas) The truck is in good shape, sound body, and frame. For the amount of use it gets I'm willing to use the plugged head if it will work. What do you think?

Thank You,
Edward

A. The Thermactor (air injection) Exhaust Emission Control System reduces the hydrocarbon and carbon monoxide content of the gases by continuing the combustion of unburned gases after they leave the combustion chamber by injecting fresh air into the hot exhaust stream leaving the exhaust ports.

At this point, the fresh air mixes with hot exhaust gases to promote further oxidation of both the hydrocarbons and carbon monoxide, thereby reducing their concentration and converting some of them into harmless carbon dioxide and water. During different engine operations, such as cruise and WOT, the thermactor air is dumped to atmosphere to prevent overheating in the exhaust system.

So the air injection would have little, if any, effect on combustion. If the casting numbers are the same, go for it.