calling out big guys. lt4 or afr
03-08-2012, 11:09 PM
#28
Most anti-AFR info is also not even considering the often overlooked exhaust flow on their heads. My heads flowed 230cfm on the exhaust using a clay fixture and no pipe or extension. That is very impressive from a 23* casting, and blows most cylinder heads exh numbers out the water even when they test with a pipe - which can be worth up to 20cfm over no pipe numbers.
If you are going to bash a company, at least use the correct information
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03-08-2012, 11:16 PM
#29
Actually, their street oriented heads LT are flowed on a 4.060 bore. Only the huge, usually race oriented heads like the 227s are flowed on a large bore - because they usually end up on large bore combinations. LT1s may be limited in bore size, but most 23* heads end up on SBCs, with aftermarket blocks like the World Motowns that can go up to a 4.2" bore. Doesn't seem like a joke to test on 4.125" bore when people can use up to a 4.200" one.
Most anti-AFR info is also not even considering the often overlooked exhaust flow on their heads. My heads flowed 230cfm on the exhaust using a clay fixture and no pipe or extension. That is very impressive from a 23* casting, and blows most cylinder heads exh numbers out the water even when they test with a pipe - which can be worth up to 20cfm over no pipe numbers.
If you are going to bash a company, at least use the correct information.
Most anti-AFR info is also not even considering the often overlooked exhaust flow on their heads. My heads flowed 230cfm on the exhaust using a clay fixture and no pipe or extension. That is very impressive from a 23* casting, and blows most cylinder heads exh numbers out the water even when they test with a pipe - which can be worth up to 20cfm over no pipe numbers.
If you are going to bash a company, at least use the correct information
.Last edited by F0x Slaughter; 03-08-2012 at 11:22 PM.
03-09-2012, 12:17 AM
#32
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Why not Brodix, Dart or Canfield? I've got brodix track 1's that flow 330+. Before that I had dart pro 1's that flowed about the same. I like the unconventional approach.
03-09-2012, 07:31 AM
#33
you cannot knock AFR's head program as much as i do like other offerings.............one thing to keep in mind is the variance in the builds that these heads are used on........ive seen far too many "slow for what they are" AFR headed motors with improper tunes/cams/inductions and exhausts........and ive seen plenty of fast ones as well.......basically what im saying is look for quantative data of two heads on the same engine.......again in no way am i saying anything against AFR they make awesome cylinder heads.......what i am saying is there is plenty of BS out there as we all know.....there are far too many people saying "this is better"......i dont tell them its not i just ask why? where is your data? me personally i like numbers and results that are logged rather than just "because they're awesome"...........in the OP's case id run the afr over the lt4 for one main reason because of the power he is intending on making........deck thickness
03-09-2012, 10:43 AM
#36
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I am refereing to LT1 results because they stepped up and offered an LT1 option. Had they not then I would have switched to something in a standard sbc configuration and converted them long ago. Good enough?
03-09-2012, 10:49 AM
#37
Yes lt4s can flow up to 300 cfm and I would say if your going to 8k rpm then use afr but if u r only going to say 7200 and using stock pcm ignition or even the 24x on a boosted application, u can get away with the lt4s. Save the $ and I hope u have a th400 behind that setup?
03-09-2012, 04:00 PM
#40
With the bore limitations of an LT1 block I really don't think there is a better race head for a 23* LT1.
If we could bore our motors out to 4.150 or more like the SBC guys with aftermarket blocks, I would probably look more towards take-off SB2.2 heads or something like the CNC'd Brodix 18* race heads that flow something crazy like 360+cfm straight form Brodix. No point though with our relatively tiny valve shrouded bore, and in the small 23* world I don't see too much competition as a whole lineup against AFR - they have killer street, strip, and race only options. They really stepped up to provide for the LT1 crowd, with bolt-on 23* heads that start to rival performance of rolled angle race heads that would take thousands in custom parts to make work.
I barely have the money to finish my heap, but I would love to see someone get a set of their 235s on a gutted 410 LT1 with a nasty 26x solid roller to see what an all motor LT1 can really do. Its about time someone starts challenging those 8 year old NA records already...I nominate Gizmo.
Threads like these still make me curse Dart for backing out of their LT1 block. I still get mad thinking about that.
If we could bore our motors out to 4.150 or more like the SBC guys with aftermarket blocks, I would probably look more towards take-off SB2.2 heads or something like the CNC'd Brodix 18* race heads that flow something crazy like 360+cfm straight form Brodix. No point though with our relatively tiny valve shrouded bore, and in the small 23* world I don't see too much competition as a whole lineup against AFR - they have killer street, strip, and race only options. They really stepped up to provide for the LT1 crowd, with bolt-on 23* heads that start to rival performance of rolled angle race heads that would take thousands in custom parts to make work.
I barely have the money to finish my heap, but I would love to see someone get a set of their 235s on a gutted 410 LT1 with a nasty 26x solid roller to see what an all motor LT1 can really do. Its about time someone starts challenging those 8 year old NA records already...I nominate Gizmo
.Threads like these still make me curse Dart for backing out of their LT1 block. I still get mad thinking about that.