I am currently running a set of Bosch plus 4 iridium plugs in my 350 TPI with a mild cam and an MSD coil with 8.5mm wires. I have read on here that bosch isn't that highly thaought of with these cars soi am swapping them out for a set of NGK V-groove. Any input on this decission is greatly appreciated. Now for the real question since the car has a cam and all that fun stuff should maybe increase my plug gap from .35 to like .40. Wouldn't this equal a hotter spark??

 

Read this

http://www.centuryperformance.com/sp...ch-spg-26.html

In my race engine, I run NGK V-groove race plugs and have them gapped at .035". I also have them indexed to keep the ground strap away from the dome on the piston.

 

You just need to buy a hotter plug. Changing the gap of the plug is not the correct way of accomplishing what you want.

 

alright thanks guys that pretty much covers that issue. car seemed to run fine when i got it with copper core autolites and that was after sitting in a barn for a year. Still don't care for the Bosch plus 4's at all.

 

Too many gimmicky plugs available.

"Our plug will increase your fuel mileage, give more power, etc"

Comparing a new regular plug to some fancy expensive plug will probably show no difference in fuel mileage or performance. Changing out any old, worn, etc plug for any type of new plug will increase fuel mileage.

For a daily driver, I'd recommend a platinum plug just because it will last a lot longer and you won't have to change the plugs as much. Typical plugs on a daily driver should last about 4-5 years at the most. Higher mileage vehicles should change the plugs every couple of years. Plugs are cheap. Don't even bother cleaning and regapping old plugs. Many new cars come with platinum plugs just because they're so hard to change.