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Author Topic:   Head mix-n-match question
ss99
Member
posted November 18, 2004 03:05 PM
I've got a 291 head that I need a match for. I've got a 461 head, but I've heard the combustion chamber design is slightly different. The chambers do look slightly different to me. Can they be run as a pair or not?

Thanks

Istock66
unregistered
posted November 18, 2004 03:30 PM           
you would be better off finding a sinlge
186 or 041 or 462.

If you really want to use the 461 and want them close just look at the chambers, you could probably open the 461 up to match the head youve got.

rico 08
Member
posted November 19, 2004 06:59 AM
I've got a 461,it's got the really small 64cc chamber...right? I'm not sure if it's been crack checked tho


ss99
Member
posted November 19, 2004 07:27 AM
The 461 and 291 heads have the same cc chambers (about 64). The issue is the combustion chamber design. They are a slightly different, and I wasn't sure if this would pose a problem.



Raz_900
Member
posted November 19, 2004 04:46 PM
I've heard the 461 is actually closer to 62 or even 60cc. And with the quench area by the spark plug being different, it would like slightly differently timing and/or make a little different power per cyl compared to the 291.

I'd buy one to match either one of them then sell the other. Should be able to break even then have a matched set.

Mixing and matching is just asking for it. "Never time or money to do it right, but always time and money to do it again."

jay116
Member
posted November 19, 2004 05:48 PM
If all you have is a mis match and you can't get a pair then run them. Just know that it wont be optimum. I mean there are people out there that build motors with 7 pop up pistons and one flat top so that when they get teched it appears they are running flat tops. It will work just isnt perfect.

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Jason Boivin
http://www.rcracing-team.com