Building up a speedster engine and I have a "Sherman Super Fire Head with 14 mm holes. Will be using a Stipe 290 cam, Bosch distributor and a Carter BB1 carb. I need a starting place for spark plug purchase.
Chuck- start with an Autolite AJ42. Its a mid range plug. There is an AJ32 and an AJ52 on each side of that. Dan
Chuck, I went with NGK Platinum. I don't have the number right now but went with a high heat range plug. Work real good. PK
Had great luck with Bosch 409 long reach plug
A good plug that we use in our ohv, and several people over here (UK) who run both z heads and prus heads run NGK BP2ES which work very well.
OOPs- AG42 not AJ42. Does not really matter, as it seems they are no longer available. Good thing I have a god stock of them. Dan
Thanks MTFCA! BTW you can get anything on ebay, even AG42's and discounted Bosch and Ngk plugs. Its decision time
I like the Bosch plugs. Sorry, don't have the number handy. Get as long a reach and as hot a plug as you can.
I've used the Bosch FR9HP with good results