NGK BPR4HS on Amphicar ?

Jacques B.

Hello guys,

Here in Montreal the weather is getting warmer and we are having some days temperatures above zero ;) so in the preparation for the summer I went today to my local parts dealer to buy some spark plugs for my amphicar. I asked for NGK BP5HS or BP6HS (as I saw on the IAOC equivalence parts) but the guy had only BP4RHS. I know that the R stands for resistive but the I don't know if the 4 will be too hot for my engine. What you guys think ?

Thanks in advance for your advice,