Hello from cross the pond the question we'd like to answer is do AFR's full CNC ported heads out flow & out BHP & torque other companies cyln heads with the same stated runner cc & full CNC port work done to them and do they out perform all others by a country mile as they would have us all believe.
This question has been raised 1,000's of times both side of the pond.
If we look @ AFR flow chart specs in there ads they certainly look to be a head of the pack . But are they really that much better for the price paid is the big question.
A little tid bit of info for you chaps might shine a little light on why there flow #'s do exceed others heads AFR flow tests there SBC cylinder heads using a 4.500 dia bore not a 4.00 or 4.125 dia bore as we all know there is no SBC engine with a 4.500 bore & flowing heads using this 4.500 dia bore will greatly increase the flow #'s due to valve unshrouding & volume of the larger bore VS
a smaller STD Chevy bore of between 4.00 for 350 & 4.125 dia for Chevy 400 cid engines.
Now this test is not for bashing AFR at all they do surperb work & there heads a high standard race proven head ...... but the big question remains are there heads really that much better then the rest eg: Ed's Canfields , Brodix , Trick Flow , Pro-Comp RHS , Dart , World ect ect.
We 'll be testing AFR's 210 cc runner heads on our Chevy 383cid engine @ 10.4:1 comp with the same bottom end as the last engine dyno test we posted
That engine was loaded with Pro_comp 210cc runner heads made 477 BHP @ approx 6300 RPM & 469 ft lbs torque @ approx 4400 RPM.
Now we'll see how AFR's 210 cc heads compare to them, looking @ ARF flow charts there should be a great increasement in BHP & torque.... will see & post our findings & dyno's print out & DVD of dyno test.. great fun.
Cheers! Dr,Dee