[What'saCobra?]

If you have a hot 351W with alloy heads and want max hp, try NGK R5671A-9, V-Power, non-resistor racing plugs. They are one of the favorites of dragster fans of FORD SB's.

The V-Power means they have a split V in the tang end, like a snakes tongue.

You should learn to start the engine without flooding it if you have no choke (I'm using Holley's new HP series carb, mechanical secondaries and double pumper) with these rather cold plugs. Not so easy when cold, but you can catch it.

Mechanical secondaries are just great because the new HP series carb has a high Q sensing curcuit and meters correctly even when the total air velocity is very low, such as at WOT and low RPM. Pulls like a train with very fast response to foot.

These plugs will foul if you jerk around and insist on big accellerator pump movement when the engine is hot and needs none. Or you fail to learn how to start a cold or hot no-choke carb.

At the first sign of too much gas (smell it?) leave the throttle wide open and wait for it to lean out, clear and start up.

Catch it without too much but just enough throttle movement.

These plugs must be indexed if you use the 1.7 rocker arm ratio (suggested, as it really wakes the engine up), rather than the standard crate 1.6.

Indexing consists of marking the top outside ceramic (you know, where the plug wird slips over) with an indelible dot where the tang attaches to the threat shoulder and tightening the plug such that the dot ends facing up (towards your eyesight), away from the piston top.

Test for clearance, however, if you have anything but a standard crate cam in your 351 and you decide to use the 1.7 ratio. It is the worlds cheapest HP increase, just a set of roller rockers.