Ported LS1 castings VS. AFR's
12-31-2007, 08:15 AM
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Ported LS1 castings VS. AFR's Can a set of stock LS1 castings be ported to flow good #'s for a stock CI 346? I have to pull the engine to replace the oil pan gasket. So I was wanting to port the heads while the mill was out. $ is tight, but I wanted to help the heads out for the LT's Im installing. Are the stock castings worth spending the $$ on? I have a buddy who has been porting heads for 15+ years and will do them for $100.
12-31-2007, 08:25 AM
#2
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Can a set of stock LS1 castings be ported to flow good #'s for a stock CI 346? I have to pull the engine to replace the oil pan gasket. So I was wanting to port the heads while the mill was out. $ is tight, but I wanted to help the heads out for the LT's Im installing. Are the stock castings worth spending the $$ on? I have a buddy who has been porting heads for 15+ years and will do them for $100.
12-31-2007, 01:32 PM
#5
This kind of comparison is old news....it was beat to death years ago when the AFR's first hit the scene.
A stock head needs material ADDED in the right places to flow more and become more efficient....and the "more efficient" is the key.
Sure, I could open up a stock casting to flow close to 300 CFM leaving paper thin walls (or worse) and it will be 225-230 cc's when the smoke clears and wont have the explosive low and midlift flow. The biggest issue will be the velocity and airspeed difference from similar peak flow (and a higher average with more area under the curve) at 205 cc's.
Bolt both of them on the same shortblock and it wont even be a contest in the way it runs....The smaller more efficient head will run circles around the other under 4000 RPM and make more peak power as well. Part throttle and response will also be night and day comparing the two.
Save your money and buy some AFR's....do it right the first time. Honestly it will save you money in the long run because you wont be the first budget build that gets a makeover down the road (or even two makeovers in some cases) because you wanted to improve your mediocre results which is all you will get with a ported set of stock castings....and it doesnt matter who does the porting. Anyone porting a stock head is already starting with a huge handicap....thats why they need to be so big to get a reasonable amount of air out of them.
Hope this helps...
Tony
A stock head needs material ADDED in the right places to flow more and become more efficient....and the "more efficient" is the key.
Sure, I could open up a stock casting to flow close to 300 CFM leaving paper thin walls (or worse) and it will be 225-230 cc's when the smoke clears and wont have the explosive low and midlift flow. The biggest issue will be the velocity and airspeed difference from similar peak flow (and a higher average with more area under the curve) at 205 cc's.
Bolt both of them on the same shortblock and it wont even be a contest in the way it runs....The smaller more efficient head will run circles around the other under 4000 RPM and make more peak power as well. Part throttle and response will also be night and day comparing the two.
Save your money and buy some AFR's....do it right the first time. Honestly it will save you money in the long run because you wont be the first budget build that gets a makeover down the road (or even two makeovers in some cases) because you wanted to improve your mediocre results which is all you will get with a ported set of stock castings....and it doesnt matter who does the porting. Anyone porting a stock head is already starting with a huge handicap....thats why they need to be so big to get a reasonable amount of air out of them.
Hope this helps...
Tony
Last edited by Tony Mamo @ AFR; 12-31-2007 at 01:37 PM.
