Thoughts on porting iron heads
#1
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To give some background information, I have to run iron heads and a 500 cfm Holley 4412. 3000 pounds, circle track.
I'm curious to hear differently theories on how far I should take my heads in respect to porting and polishing. From various flowcharts I've seen the iron heads flow very well compared to most of the available sbc market (I know they're not up to par with 243's, but they're what I have to run). While most in my class are going to sbc 410-430cu. in., I'm actually going in the opposite direction to try and spin it a little harder (7500-7700 rpm) with a 333.
Cam is 270/274 604/612 109. Am I wrong for thinking a simple port match and polish will be sufficient for my set up given the limited carb intake? I'd like some opinions, theories and questions for my own research when I deliver my parts to the carb and head builders.
I'm curious to hear differently theories on how far I should take my heads in respect to porting and polishing. From various flowcharts I've seen the iron heads flow very well compared to most of the available sbc market (I know they're not up to par with 243's, but they're what I have to run). While most in my class are going to sbc 410-430cu. in., I'm actually going in the opposite direction to try and spin it a little harder (7500-7700 rpm) with a 333.
Cam is 270/274 604/612 109. Am I wrong for thinking a simple port match and polish will be sufficient for my set up given the limited carb intake? I'd like some opinions, theories and questions for my own research when I deliver my parts to the carb and head builders.
Last edited by 408GOat; 11-15-2016 at 08:42 PM. Reason: On my phone
#2
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Bowl work and a sexy valve job. Either find some LS6 or get the Katech hollow 2.10" valves and have them turned down. Light light light. Did I mention LIGHT
Then you will only need a 255/260 duration to support your target RPMs Leave that 270 stuff for your competitors 400 plus inches
Your combo will rip if you maximize the cylinder pressure. Tight quench and stable valve train. Killer bee hives and Ti retainers if rules allow. Definitely go E85 if you can and for sure a .130" (dominator) style needle and seat assembly in that 4412. With only one bowl of fuel volume; your fuel system,tank,lines,pump,regulator all need to be able to FEED. lean makes torque but it ruins engines and you can't win if you're sitting in the stands watching
Then you will only need a 255/260 duration to support your target RPMs Leave that 270 stuff for your competitors 400 plus inches
Your combo will rip if you maximize the cylinder pressure. Tight quench and stable valve train. Killer bee hives and Ti retainers if rules allow. Definitely go E85 if you can and for sure a .130" (dominator) style needle and seat assembly in that 4412. With only one bowl of fuel volume; your fuel system,tank,lines,pump,regulator all need to be able to FEED. lean makes torque but it ruins engines and you can't win if you're sitting in the stands watching
#3
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Anything headwise is fair game except for aluminum heads. I started to look into valve work, but admittedly I'm not too keen on it just yet. I'll definitely look into the LS6's though try to study up on them. Unfortunately e85 is against our rules as well as methanol and alcohol. Fuel system shouldn't be an issue I don't think, we have to run a mechanical fuel pump. Thanks for the input
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#4
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Despite what most people think port work isn't about maximum flow it's about efficiency. Efficient heads will make more power with less fuel and air and over a wider area. If you have it in the budget spend the money on the heads/intake port work and cam/valvetrain.
#5
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If you have to run a mechanical fuel pump, Wagner Automotive Research right here in Markesan, WI sells a front cover for circle track applications to run a mech pump and even a distributor off the front of the cam
Also Brzezinski racing in Pewaukee does an awful lot of iron LS heads for roundy round guys. Look up castheads.com
Also Brzezinski racing in Pewaukee does an awful lot of iron LS heads for roundy round guys. Look up castheads.com
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Tim Fuller won the super dirt week small block race this year with one of those Wegner spec engines. Not sure of the exact specs, but even on the 5/8ish mile Oswego track he had the open motors covered. Love to see the LS stuff coming to circle track racing