Does anyone have a good recommendation for spark plugs on a 1968 427?

AC Rapidfire plugs. The application is RF 4...you won't do better.

Ditto!!!!!! Not too many autoparts stores have them, but well worth the search.

JR

If you have headers, you might need shorter plugs.  What do you have right now ?  Were you happy with it or just looking for options since you are doing a tune-up ?

I am currently running ac r43xls plugs and my vette is running very strong. I had the same question you do. Below is a letter I wrote to AC Delco and their response which I thought was relatively non committal. Plugs seem like a personal preference thing to me at this point.

The reason I had the question was, it seemed like after plugs were 1 month old my vette had a hard time starting cold and a really hard time when hot. The issue for me turned out to be my brand new TI amp (with updated chip) just was not sufficient to fire up the engine. I left the stock amp installed for appearance but hooked up an MSD amp. I painted it flat black and tucked it in the fender well by the gills. No more fouled plugs and it starts in a heart beat hot or cold and it runs great.

Letters

To: ACDelco:

I have a 1969 Corvette with a 427 tri power, 435hp, 11 to 1 engine. I tried the Rapidfire #4 plug and liked them a lot. I felt they delivered everything your advertising said they would. My mechanic tells me these plugs are not good to use in this engine. He prefers r43xls. Is he right? Is the r43xls a better choice than the rapidfire #4? I have also tried r44xls and r45xls. I did not notice any appreciable performance difference between any of the r**xls plugs. I did feel that the rapidfire out performed the xls choices. Curious what your opinion on this topic is.

 

  Thanks,

  Jim

 

From: ACDelco

Thank you for writing ACDelco.

Thank-you for your e-mail Mr.Riddiford regarding your 1969 Chevrolet Corvette.

According to our records the following ACDelco spark plugs are recommended for your vehicle;

ACDelco Platinum plug 41-828

ACDelco Rapidfire plug 4

ACDelco Standard plug R43XLS

ACDelco Standard plug R44XLS

Anyone of the above choices are acceptable for use within your vehicle.

If we can assist you further, please contact us at www.acdelco.com

Thank you for your interest in ACDelco.

ACDelco Customer Assistance

I purchased the Rapidfires thanks, on a related note: on the Drivers side the plugs are so close to the header when I put the plug wire on they actually touch this cant be a good thing. Any one have an answer to this?