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Discussion Starter #1
Hey I am sorry if this has been asked before, I have searched on here a great deal and found tons of info on the famous 245 ap heads but not as much on the smaller 227 heads. I have a set of these with the 2.150 valves. My question is what is the power potential with these, na, of course? And what size engine are these best suited for. I have always had good luck with conventional 406 setup, but I am going to buy a dart block now and will I be ahead to go 421. This is going to be heavy nitrous application sometimes. Thanks again, Josh
 

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EFI/N2O JUNKIE
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They will work better with a larger bore, like a 4.155 or bigger. I am running mine on only a 4.130 bore, didn't know better at the time.......

And those RR227 heads are where the RR245's come-from. You aren't talking about their AP220's are you?
 

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Discussion Starter #4
They will work better with a larger bore, like a 4.155 or bigger. I am running mine on only a 4.130 bore, didn't know better at the time.......

And those RR227 heads are where the RR245's come-from. You aren't talking about their AP220's are you?

They are for sure raised runner and say 227 on them. I hear they are the same casting as the 245s but my budget can't handle the cnc upgrade right now. Thanks for the help!
 

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Discussion Starter #5
Also what power potential am I looking at? I have not flowed these but they should be in the low 340 range I would think. Basically what I want to hear is, on a 13:1 406-421 with proper solid roller will they make 725 or is my figuring wrong?
 

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EFI/N2O JUNKIE
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You should be close with the correct intake. I am only running a 2.125 valve on a 4.130 bore, 3.875" stroke, 13.5:1. I have to assume that either someone ported these heads or they were bought with one of Bob's programs run on them already. Obviously the RR245 program wasn't done to them.
 

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Discussion Starter #7
What kind of times are people getting out of these? I am have to weigh 3150 on a 275 limited to an .082 nos jet. What is a realistic e.t. to expect in the 1/8? I am shooting for 5.6x's
 
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