Spark plug advice for my '70 LT1

[Kenneth H.]

I've searched the archives without success and was wondering if anyone had a suggestion about which spark plugs to use. I expect to put about 200 miles per year on my LT1, mostly around town. I do have a lead foot, but I won't jeopardize my investment by overtaxing the engine. Typically I drive the 'vette not more than 20-30 minutes at a time. The original plugs were R43's and the currently installed plugs are off brand, aftermarket plugs.

Anybody have any suggestions?

Thanks,

[Dick W.]

Re: Spark plug advice for my '70 LT1

Modern day equivilent of R-45 should work nicely for the type of driving you are talking about

[Richard T.]

Re: Spark plug advice for my '70 LT1

I use what the factory installed when the car was built. I have not had good results with OEM spark plugs. Your engine calls for a AC R43. If you are having fowling problems due to oil burning try a higher heat range AC plug in the affected cylinders. I also prefer the single wire electronic ignition over the stock point. This is OEM but it is by far a improvement you will notice over a stock factory installed point system. If you are lucky and you have the factory electronic system that is great. Just my opinion; to each there own on this subject.

[Kenneth H.]

Re: Spark plug advice for my '70 LT1

Dick and Richard,

Thanks for your replies. Not knowing alot about spark plugs I was trying to figure out which to install in place of the aftermarket plugs. I'm trying to get my LT1 back to "as original as possible", but also to get a set of plugs that were correct for my type of driving. I'm not having any problems (that I'm aware of) with the plugs that are currently installed.

It seems from what I've read, the original R43s are best suited to driving the LT1 the way it was originally intended to be driven (i.e. fast and hard). The R45's seem to be better for the type of driving that this 'vette will see now and in the future. I have an opportunity to buy a set of NOS R43Ts from a friend, but I'm not sure if this is the correct move.

I guess I'll pass on the R43T's, take Dick's advice about the modern day R45 replacements (AC) and try to find a set of AC R43's for future judging. Does this sound like the right plan?

[Jim T.]

Re: Spark plug advice for my '70 LT1

Not recommending, but I use Champion J12's in original owner 68 327/350 that has 11:1 compression and has not been rebuilt.
No complaints.