70 LS-5 (new to me) lights up at night under the hood. Running rough!!!

[Terry M.]

Re: 70 LS-5 (new to me) lights up at night under the hood. Running rough!!!

I believe you are right John. IIRC 1970 LS5 (at least in Corvette) used the smaller peanut 7/8-inch hex tapered seat plugs. This was one of the first uses of those plugs. Don had best check his car to be sure of the correct application.

[Bob H.]

Re: 70 LS-5 (new to me) lights up at night under the hood. Running rough!!!

The R45T should be correct for the 70 LS5.

[Thomas H.]

Re: 70 LS-5 (new to me) lights up at night under the hood. Running rough!!!

The R45T should be correct for the 70 LS5.

Agree.

I run the R45T plugs in my 71 LS5.

Tom

[Duke W.]

Re: 70 LS-5 (new to me) lights up at night under the hood. Running rough!!!

I checked my old AC Spark Plug catalog, and it lists R43T for '70 Corvette 454, 390 HP, so the R45T should be "correct" for this application with the empirical heat range adjustment. The listing for '69 is R43XLS, so I expect the '70 is an open chamber head.

Duke

[Roger G.]

Re: 70 LS-5 (new to me) lights up at night under the hood. Running rough!!!

I don't know if it makes a difference but the 70 LS5 I believe is a closed chamber head.

They went to open chamber in 71?

Going from memory.