Yesterday was tune up day and I must have spent two hours and two bandaids removing and replacing spark plugs. This simple job requires an assortment of 5/8th wrenches and I have to hit three plugs from under the car. When I bought my '71 the previous owner had installed headers (manufacturer unknown) but he gave me the original exhust manifolds. So I have a couple of questions...

1 - If I change back to the original exhust manifolds, will it be easier to hit the plugs?

2 - Will there be a noticible decrease in performance?

The '71 is a 350 with manual transmission.

Thanks for any advice I can get?

Lidia

Lidia,

There's a tread on changing spark plugs in the C3 Engines forum that might help find an answer for you. I have the stock manifolds on my '70 300hp/350 and was able to get at all the plugs from above with a wobble joint and rachet with a regular spark plug socket. Getting the old plugs out was easier than putting the new ones back because vision was blocked by the manifold, even with all the shielding removed. I don't know how much difference there is in headers from manufacturer to manufacturer, but would guess that they'd all be concerned about keeping access to the plugs a top priority when configuring their pipes.

Several friends are proponents of headers with the only downside ever mentioned is the increase in heat in the engine compartment, which eventually finds it way into the interior of the car. Installing more insulation under the carpet and wrapping the exhaust system have been suggestions thrown about for ways of attempting to cut down the increase in heat.

As far as whether or not there is a big change in performance, I can't answer that specifically. The afore-mentioned friends are always saying that the better an engine breathes (input and output), the better it will perform. And headers are typically less restrictive than stock manifolds. I upgraded to larger pipes on the rest of the exhaust system (2 1/2" versus 2") when I replaced everything aft of the manifolds last fall. Seems like the "ol' girl" has a little more snap now when I put the foot down (but that may be more wishful thinking than reality) and the sound is definitely throatier.

Hope that helps some.

|UPDATED|3/12/02 10:34:02 AM|/UPDATED|

Hey Kiddo, if you go back to stock exhaust, will it be easier to reach the plugs? Guaranteed. Will there be a loss of horsepower? Yes. 15 to 25, possibly a bit more.