I have a LS-5 with the stock heads(3964290)and Im looking for a little more performance.I have TRW forged pistons #L2465.Cant afford aluminum,Ive been told there is possibly a better GM iron head that I can use (open chambered?) versus what I have now with these pistons.Trying to stay less than 10.5 cr which I believe Im around now.Cam is .544 .544 lift,dur 230,230.Thanks.

Looking up that piston in the sealed power piston section of the summit catalog, shows it to have 10.68:1 with a 106.9cc head. Using it with a 119cc head should give you around 9.6:1 compression. With 9.6:1 compression good pump gas should work fine. I would look for a good open chamber "large" oval port (do not buy a set of the peanut port heads). Two of the most popular part numbers are 781 and 049 (last 3 digets). By the way the closed chamber crowd really likes the 290 heads you have as many go fast with them.

Thanks Mike,Are the heads I have now the 106.9 cc you quoted the c.r. for?If I went to a 781 or 049 head would I see any significent gain or would I just be doing a lot of work for nothing?Thanks again.

I'd just add 2.19/1.88 SS valves with alittle pocket porting to your current 290's.

That's a great head casting.

Doug...what are you trying to do with the car, and what sort of gains are you looking for. Im no expert on this, but I would think that with the only change being the heads you're talking about, you will not see any difference at all....with a loss in compression ratio, you're looking at a loss in power, not a gain. The 290's are good heads, just my opinion. That's a lot of work and money for nothing. Let's see what others say. John

I have 290's with 2.19/1.72 valve combo. Mild porting int & exh. Chambers finished up at 104CC after some unshrouding. These are decent heads. What are the rest of the specs on the cam you are running? Your motor should run fairly strong right now. What about the rest of the combo?

Doug, IMO both are great street heads. I have seen the debate over open vs closed heads and have come to the conclusion that there is little performance difference between the two. My only concern with the 290 head is that you may have a issue running pump gas with the higher compression ratio it will give you.

Thanks guys,I do blend in 10 gallons of Sunoco 100 every other tank of 93.I was told (possibly incorrectly)that I could gain more by going to open chamber, but from what Im hearing probably just a correct performance valve job would be in order.The rest of my combo is Crane gold roller rockers,Edelbrock C-396 manifold with a 770 Holley street avenger,Cloyes tru roller chain,Hi volume oil pump,MSD 6AL with a Pro billet dist.,Blaster 2 coil,Heddman ceramic headers,Borla stainless exhaust,Centerforce clutch,M-22,Moser posi with 3.73 ratio on Goodrich 225-70/14 tires,complete Hotchkis suspension front and back.Just my weekend cruiser,never had it to the dragstrip,but I am definitely going to do it this year.Car seems to run pretty good ,I was just looking for a little more.Thanks again to all for your suggestions.