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Author Topic:   Piston/Head combo?
CA Dirt guy
Dirt Roller

Total posts: 11
posted December 26, 2004 08:00 PM  
I'm trying to decide which cylinder heads to use. I can use any cast iron head unported. I must use the Holley 4412 Carb. No compression or cranking limits. I'm shooting for 12.5 to 13.5 to one.
I was considering Pro Topline "Pro Lightening" 50cc with flat top piston or World "Sportsman" 64cc with domed piston. It sounds like its better have no dome but the Pro Topline 50cc seems kind of limiting as far as compression adjustability, due to the fact that only a few companies make pistons with domes for this brand.
Anybody with ideas or opinions on these heads would be great.

Eric

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted December 26, 2004 08:13 PM  
Guys in the southeast are angle milling the 50cc ones down to around 38cc and running flat tops and doing VERY well.
That'd be my recommendation, as they are a lot better head than any 64cc head.

KP

bbracer17
Dirt Freak

Total posts: 278
posted December 27, 2004 09:17 PM  
I would agree with KPLugnut also, the flat top pistons will be lighter than the domes and will get great compression when angle milling the heads.

CA Dirt guy
Dirt Roller

Total posts: 11
posted December 29, 2004 08:21 AM  
Thanks for the info. Do you know anyone who has run that brand of head and how good they are, besides the head volume and compression? How well do they work with that 4412 carb. I'm not real familar with that carb and how far you have to go to make it work. There seems to be some really pricey carbs out there considering the carb is supposed to remain stock for alot of classes.Are these mods considered "JETTING"?

Eric

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