1963 Classic Spark Plug Help!

Hello fellow Ramblers!
Looking for some help with spark plugs for my engine please.

I have a 1963 Classic with the Straight Six 196 OHV Cast Iron Engine.
The 1963 TSM shows an application of either an H-10 or H-18Y Champion spark plug.

Well after getting off the phone with a tech at Champion, here is what he said.

The H-10 is a lawn mower engine plug for a Briggs and Stratton.
The H-18Y is a plug that is 3 heat ranges higher than the H-10 and didn't recommend a plug that was 3 ranges higher in the engine, one maybe, but not three.
So, he really couldn't help out.

Also the TSM doesn't mention  any different spark plugs than the ones above.
So, I can't believe that the above spark plugs are suitable for all three different engines that went into the Classic... V-8, Aluminum Block, Cast Iron Block. But like I mentioned, there are no other spark plugs mentioned in the TSM.

RockAuto shows a Champion 405 which looks way too long and would likely hit the piston.

I'd appreciate any advice on the spark plugs should I put in the engine?
Kind Regards

According to my '65 American TSM (uses the same engine) the H10 was for the flat head 196's and the H18Y for the OHV. I put a set of H18Y's in mine and it runs just fine. Whoever you spoke to at Champion is just looking at a computer and has no idea what was used "back in the day".

pit crew wrote: The Ramble wrote: I'd appreciate any advice on the spark plugs should I put in the engine? When in doubt follow the manual. I did had to chuckle when I first read your post. My personal choice for spark plugs in generation 2 V8s is the RC12YC. Every time I request a set the person at the counter hands me one instead of eight. When I say I really need eight I get strange looks and questions as to why I would need eight "lawn mower" spark plugs at one time.

I too found it a bit amusing. Although the champion rep. probably gave you the absolutely correct information based on data that is used some 50 years after the fact.
As to the later year v8's some times referred to as Gen 2?
I prefer the RC9YC which is about 3 heat ranges colder, stock number 344.
However if one looks at a period correct Champion catalog, the RH18Y is correct for the OHV 196, stock number 857 and the RH10C is correct for the Flat head engine and the stock number is 854

The Ramble wrote: pit crew wrote: [QUOTE=The Ramble]I'd appreciate any advice on the spark plugs should I put in the engine? When in doubt follow the manual. I would love to follow the manual but the darn thing lists two different spark plugs but doesn't mention which plug goes to what engine.

It's a TCM, back then you were supposed to know that....

The Ramble wrote: Thank you, DocCreer,  rocklandrambler, pit crew, uncljohn and Wrambler I will go with the Champion H10C plugs. If I see any fouling, I will switch to the H-18Y plugs. Much Obliged.

The H10 is for the flat head 196. You want to use H18Y for the OHV 196. Why pay for something you're going to have to change out again?