I have a low horsepower GM 350 replacement crate motor in my 68. I prefer Autolite plugs. Confused on whether to run Autolite #26 or 605 plugs. Quite a difference in depth they go in and the total length. No headers, stock ignition. What do you run?

Thanks

If you have Vortech heads you need to use the Auto Lite 605. That is a good plug for that combo. You really need to tell us what heads you have on your engine. :D

I'm sure it's not Vortech heads. This is a low horsepower (somewhere between 220-250 horsepower) stock GM 350 replacement engine. So you're saying the 605's are strictly for the Vortech heads?

I'm guessing it takes a tapered seat plug. Try the Autolite 24.

Paul,

I use AC Delco R45TS plugs. Cross that number to the Auto Lite. :D

Make sure you get the right plug, it depends on the head more so the engine, my heads call for the 3924's which have long threads to reach deep into the combusion chamber.

Make sure you get the right plug, it depends on the head more so the engine, my heads call for the 3924's which have long threads to reach deep into the combusion chamber.

I think 3924 and 24 are the same heat range. The 24 is a tapered seat plug, and the 3924 is a gasketed plug. I used the 3924 with my AFR180 heads, and the 24 with my Dart IE180's.

my old stock heads took plugs much shorter than those though, so if he is running stock he deffinately shouldn't be running that size. (unless his calls for it of course, im just saying mine were very very different in size).

The motor should have some paperwork with this information though, especially if you bought it.