Shopping for heads...Dart, AFR's, Brodix
#12
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I would get the cnc versions. And get them bare. I didnt do either and ended up doing all of the above work anyway! Hand porting was about 20 hours and they are not exact, you dont get inconel valves and wider valve seats. 325-335 for 502. They will still work good on a naturall aspirated 540 and make a ton of torque. Greg
#16
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If you are running a supercharger you will be wasting your money buying heads. Just use the stock rectangle port heads, they will flow all the air you need. The blower will push plenty through them! They have 320 cc intake ports and big combustion chambers. Buy some blower pistons instead, so you can pump up the boost without worry!
Sincerely
Dennis Moore
Sincerely
Dennis Moore
#18
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I dissagree. For comparison the stock GM exhaust ports flow less air than a ported A/M small block chevy head. In a situation like this you will end up with higher boost pressure. My 540 made over 900hp with A/M aluminum heads hydraulic roller cam 8lbs of boost 92 fuel. Dennis, do you honestly think that could be done with stock GM heads?
#19
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I was told that with better flowing heads, that the HP will increase. I was also told the boost will drop a little, but I could increase the boost with a different pulley and make even more HP. This does make sense to me.
What are your thoughts JimV???
What are your thoughts JimV???
#20
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29 scarab
Thats correct. Lets you have a stock set of GM heads with 6 lbs of boost making 600hp. You have your heads ported and increase airflow 20%. The hp numbers will increase to 650 and the boost will drop by 2 lbs. You then change pulleys to get back 6lbs and gain another 30-40 hp. (The numbers may not be correct but you get the idea)
Thats correct. Lets you have a stock set of GM heads with 6 lbs of boost making 600hp. You have your heads ported and increase airflow 20%. The hp numbers will increase to 650 and the boost will drop by 2 lbs. You then change pulleys to get back 6lbs and gain another 30-40 hp. (The numbers may not be correct but you get the idea)