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Author Topic:   49cc heads
posted August 17, 2003 10:54 AM
Both Dart and ProTopline have some decently priced 49cc heads. Anybody know which is the better performer?

And for a carb restricted class (350 cfm), which runner size is best?

And is there any real performance difference between angle plug and straight plug designs?


[This message has been edited by istock59 (edited August 17, 2003).]

posted August 17, 2003 12:18 PM
As far as Dart or Pro Topline, it all depends on who you ask, According to Dart, the Pro head is a copy of theirs. Pro Topline says they're not. Everybody has their own personal preference for one reason or another.

I can't give an honest answer on the runner size you'd want to run, i'd assume small with a small carb.

I've been told by Dart and Pro Topline and their distributors that angle plugs make no more power than a straight plug design. The only advantage is header clearance.

posted August 17, 2003 12:41 PM
angle plugs are for dome to plug interference.

posted August 18, 2003 03:54 PM
Does anyone have any flow numbers for these heads?

- Brian

posted August 18, 2003 09:11 PM
i think the darts are the nicest of the 2 heads. angle plug is no advantage unless your running domes (which im gonna say your not with 49cc heads!) if it were me i'd try 180cc heads but i have heard that larger runner heads are still usefull in a limited carb motor. maybe try 200cc? also try to get your compression around 14 to 1 with that little carb. it will run like **** then!


posted August 19, 2003 07:48 PM
the flow numbers that pro topline gives are on a HUGE bore small block that noone would ever build or wouldnt even live the casting of the pro's seems to be softer material than the darts, meaning they crack.

Buy the darts, but beware you might have to do some machineing down the sides of the pushrod bore to make clearance for the pushrods.

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