SparkPlugs
My preference, and biggest bang for the buck is...
BOSCH PLATINUMS, WR7DP good for about another 3 hp and noticable in the seat of the pants. $2.99 each
I haven't tried the following, but Bosch also makes double and 4 prong plugs... up to 5.99 each and ALL their RECOMMENDED Platinum Plugs are GUARANTEED to make a difference or your money back. In this case the WR7DPs.
The 2 and 4 prong EQUIVALENTS for the WR7DPs are #4310 for the Plus 2 and #4477 for the Plus 4.
IAP sells the BOSCH Platinums under the following IAP part numbers:
Single | 31509 | 2.95 |
Dual | 31512 | 3.99 |
Quad | 44774 | 5.99 |