AFR 225 Question
09-04-2005, 06:30 PM
#1
AFR 225 Question Ok I talked to Tony at AFR and he told me that they currently offer only 72cc chambers in the 225 head. How in the world are some other companies online such as TSP and LS1speed selling AFR 225 heads in 62cc, 64cc, 72cc and 76cc? Are the 62cc and 64cc heads the 72cc head milled down?
SLP offers a 62cc in the AFR 225 and they told me the highest lift cam wiht a 6cc dish piston that you can run without having any PV issues was .596. This leads me to believe those heads are the AFR 225 72cc heads milled down. Does this make sense to anyone else?
Would I be better off running a 62cc head with .596 lift or running a 72cc head with a much bigger (.63x, .64x) lift?
SLP offers a 62cc in the AFR 225 and they told me the highest lift cam wiht a 6cc dish piston that you can run without having any PV issues was .596. This leads me to believe those heads are the AFR 225 72cc heads milled down. Does this make sense to anyone else?
Would I be better off running a 62cc head with .596 lift or running a 72cc head with a much bigger (.63x, .64x) lift?
09-04-2005, 09:44 PM
#2
Assuming you are looking for an "11 to 1 ish" final compression ratio, you need to get with SLP on their small dish piston (6 cc's I believe) which will get the CR you are seeking with a small mill on the large chamber 72 cc 225's (you need about a 67-69 cc finished chamber volume depending on exactly how high you want to go....if my memory serves me right, 67 cc's yeilds about 11.25 to 1).
And just to re-clarify, AFR does NOT offer a 225 with a chamber larger than 72 cc's, and SLP shouldn't be advertising a 62cc cylinder head (unless they are taking a healthy mill from a 72 cc version)....I believe they are just advertising a bit to early regarding the release of our small chamber 225 which is in the works and hopefully coming soon. AFR does not recommend milling lower than 66 cc's if you are trying to take the most advantage of the cylinder head, although I know a few shops that milled them lower and still had good dyno results when the smoke cleared (but it wouldn't be MY first choice....I would wait for the small chamber 62cc release).
Regarding camshaft, I find it hard to believe that a notched aftermarket piston would only tolerate .600 lift, but I would try getting with someone at SLP to verify whether that is or isn't the case. My guess is you could fit quite a bit more cam than that assuming a reasonably sized valve notch (.100 +)
Hope this helps....
Tony
And just to re-clarify, AFR does NOT offer a 225 with a chamber larger than 72 cc's, and SLP shouldn't be advertising a 62cc cylinder head (unless they are taking a healthy mill from a 72 cc version)....I believe they are just advertising a bit to early regarding the release of our small chamber 225 which is in the works and hopefully coming soon. AFR does not recommend milling lower than 66 cc's if you are trying to take the most advantage of the cylinder head, although I know a few shops that milled them lower and still had good dyno results when the smoke cleared (but it wouldn't be MY first choice....I would wait for the small chamber 62cc release).
Regarding camshaft, I find it hard to believe that a notched aftermarket piston would only tolerate .600 lift, but I would try getting with someone at SLP to verify whether that is or isn't the case. My guess is you could fit quite a bit more cam than that assuming a reasonably sized valve notch (.100 +)
Hope this helps....
Tony
09-04-2005, 09:56 PM
#3
Thanks Tony!
Well the guy that I talked to at SLP said that the 62cc head was in stock and ready to be shipped. Being that he told me the highest lift cam you could go was .596, it leads me to believe those 62cc heads are just the 72cc heads milled quite a bit! But then again, he told me I needed a 7.450 length pushrod?!?!
I think Im just gonna stick with the 72cc head and a huge cam!
Well the guy that I talked to at SLP said that the 62cc head was in stock and ready to be shipped. Being that he told me the highest lift cam you could go was .596, it leads me to believe those 62cc heads are just the 72cc heads milled quite a bit! But then again, he told me I needed a 7.450 length pushrod?!?!
I think Im just gonna stick with the 72cc head and a huge cam!
09-05-2005, 06:53 PM
#5
Check piston to valve....it's the only way to know and needs to be done anyway. Don't be listening to your buddies or even anyone at SLP for that matter. There are way to many variables and checking P to V is simply part of the engine building process. You might have nothing or you might find you have a ton, but checking your motor is the only way to find out.
Tony M.
Tony M.
