Not LS based but need to know which plug for a 250 shot. Set up is SBC 377 w/ 13.6:1 . Current plug is an autolite AR3933. Thanks in advance. Sean.

 

Not sure about an Autolite, but in an NGK, if it were mine, I'd be looking at a -10 heat range plug in the correct thread and reach for your heads. This should be about right for your compression and shot size.

 

I have a sbf 13:1 on 250 hits I use a ngk -9.

 

Yeah but what is the part #.

For example a b8efs in NGK is a 8 heat range plug for an LS motor with a tapered seat.

a r5671A-8 (I think thats the part number) is also an 8 heat range plug but it is a gasket seat plug but it is still an 8.

 

Call NGK and ask for Brandon. Very helpful guy and will point you in the right direction for an NGK plug.

Here is a link to the thread I posted.

https://ls1tech.com/forums/nitrous-o...trous-fed.html

 

Yea I run the r-15671a-7 n/a then r-15671-9 for nitrous.

 

^^ correct