[Rick_L]

Just watched the video. Many of the characteristics pointed out were similar to the SBC Dart Buick heads I ran on a drag race engine back in the early 90s. Those made huge power compared to regular Chevy heads, including some raised port Brodix heads. I think the LS3 heads may be even better. And they are factory!

 

[Rick_L]

First, if you have an LS1, 2 or 6 and you've upgraded to a FAST intake,

I would regard having an LS1,etc. with a FAST intake as having gone down the rabbit hole too far to go to LS3 heads. You'd be better off starting over and selling the LS1 as is. And the stock LS3 manifold (which doesn't cost $1000) works about as well as its $1000 counterparts. You can get into a similar modification trap on almost any attempt to get more power from an already modified engine of any type, this is not really an LS problem.

Cathedral port heads are not shabby either for that matter. They flow very well for what they are due to the tall port.

My personal opinion is that reversion problems are cam timing related not head flow related. Most LS1 cams have a lot of lobe separation angle, which reduces overlap and reversion. If you stray away from that, reversion is what you get. The big LSA is why a stock LS6 idles at 500 rpm but can make power to over 6000 rpm.

 

[Rick_L]

Raising the floor with epoxy or weld and raising the roof by material removal is a time honored way of modifying most any OEM head.

 

[Rick_L]

nad427, those symmetrical port splayed valve SBC heads will make huge power. I'm sure the ports and valves are quite a bit bigger than the LS3 ports. Best I know the only common use of them was on the old Pro Stock Truck class in NHRA back around 2000. They are not real "hemi" heads, they are "semi-hemi" in the same sense that a BBC is. I don't think there were ever cast intake manifolds for those heads - they were all fabricated sheet metal. The lifters may be keyed roller lifters which don't require tie bars. They are still sold in the Chevy Performance catalog, only in "rough machined" or "semi machined" configurations, with no valve guides or seats. The heads must be prepared by a professional head porting shop.

There were symmetrical port BBC heads, kind of. The Oldsmobile heads that Warren Johnson developed for Pro Stock in the 1990s were symmetrical port, as are the current DRCE Chevrolet heads used in Pro Stock.

The Dart Buick small block heads that I mentioned earlier were symmetrical port also.

Actually I'm not sure that "symmetrical port" is the correct description - maybe it's "non-siamesed".

 

[Rick_L]

SB2 heads fit a regular block. Requires special pieces but not the block itself.

The R07 won't fit a regular block to my knowledge. And I don't think the splayed valve heads will either. I was surprised to see R0x heads on the Jegs website.

 

[Rick_L]

The BBC heads on the long block I pictured (with the radical pushrod angle) ARE actually Sonny Leonard full hemi heads.

OK, I thought you were talking about the SBC splayed valve heads.