L-88 Closed chamber 842 head spark plug type

[Tim S.]

I have a set of closed chamber "842" heads cast in July and August of 1968.
They have installed the long reach plug Champion J60's. I think the guide shows the OEM plug was an AC43 which I think is the short tread plug. I know the Champion was not the OEM plug but I am wondering if all the aluminum alloy closed-chamber 68-69 L-88 heads were designed for the longer plug?
Thank You

[Patrick B.]

Re: L-88 Closed chamber 842 head spark plug type

Aluminum 392, 842 and 074 (open chamber) heads all required full threaded long reach plugs. Although you see AC 43N plugs listed for them, it is a mistake. I think AC 43XL is a fully threaded plug for aluminum heads but it is probably out of production anyway. Stick with Champions.

[Wayne M.]

Re: L-88 Closed chamber 842 head spark plug type

I have a set of closed chamber "842" heads cast in July and August of 1968.
.....I am wondering if all the aluminum alloy closed-chamber 68-69 L-88 heads were designed for the longer plug?

Yes, a longer threaded section. From Chevy '68-'69 tune-up specs: 427/430hp (ie. 842 heads) takes either AC 43XL (std) or AC 42XL (cold).AC43N vs AC43XLS.jpg

[Joe L.]

Re: L-88 Closed chamber 842 head spark plug type

I have a set of closed chamber "842" heads cast in July and August of 1968.
They have installed the long reach plug Champion J60's. I think the guide shows the OEM plug was an AC43 which I think is the short tread plug. I know the Champion was not the OEM plug but I am wondering if all the aluminum alloy closed-chamber 68-69 L-88 heads were designed for the longer plug?
Thank You

Tim------


The AC 43XL is the correct original plug for the closed chamber aluminum heads. As far as I can tell, it's no longer available. However, I believe the R43XL is still available.

I would not use either one. I prefer Champion spark plugs for Chevrolet engines. The current part number for your application is 120.

[Tim S.]

Re: L-88 Closed chamber 842 head spark plug type

Joe

I have not been on for a while but you are always helpful.
Thanks
Tim

[Tim S.]

Re: L-88 Closed chamber 842 head spark plug type

Wayne thank you for the pics
Tim