Has anyone used an LSA (4863) head in an N/A application? I know they are hard to find, but I would think they would flow better than a typical LS3 (823) head. From what I found, the LSA heads have a 12 degree valve angle. I know the intake port is still the same, but the 12 degree valve angle should help. That is the angle that most aftermarket heads use. That would be awesome if the LSA heads could be ported to make about the same HP as AFR or Trick flow heads. Stock LSA heads (new) are half the price of aftermarket heads. That would be a better deal if they make similar power.

I know the power gains with a stock CID engine would be minimal, but I was thinking about using the LSA heads in a stroker application. The LS3 (823) heads seem to do ok in strokers, but the aftermarket heads appear to make at least 20-30 hp more. I'm not sure if that is all because of valve angle, or if the port design is that much different. If you use the same valves, how do you think ported LSA heads would compare to an aftermarket head?

 

I just checked, the LS9 valve angle is 15 degrees, not 12.
They are made using the same basic molds most rectangular heads use, so the valve angle would be the same.

 

Yes, the LS9 heads are 15 degrees from what I found. They are a different casting number though. From what I found, the LS9 has 1771 heads. The LSA is 4863. I found the LSA info on Summit and On All Cylinders websites. They both say the LSA has 12 degree valve angles. I’m not sure if there is any other way to confirm that.

 

Only way to know if they are better is to flow test them against a 823 head.

 

LSA heads are 15 degrees. The only OEM head with a 12 degree valve angle is the LS7. The LSA (and LS9) castings are made from a much better material (through process) than an average LS3 head, but they are essentially the same casting design.
​​​​​​….edit…I love Summit Racing, but there are tons of errors on their data pages.

 

If the LSA heads don't have a 12 degree valve angle, then I wouldn't want them. I'd rather have the 821 heads with hollow stem intake valves. I'll probably look around some more to see if I can find any other sources of information on the LSA heads. I like Summit too, but I know their specs aren't always completely accurate.