Well I think those pistons are perfect. Nice find and if I run stock rods how often can i spray? If the forged rods can take more I'll get a set. Ima do some research on head you posted. Any cam suggestions since I was toldthe one I like sucks.

 

Stock Gen 3 rods are strong up to 600whp. Over that and it can be a gamble depending on tune. With a good E85 or race gas tune they could probably stay happy up to 700whp.

Gen 4 rods are considerably stronger, but won't work with the above pistons since they use an aftermarket style .927 floating wrist pin.

As an alternative to the trick flow heads, you can get PRC Stage 2.5 5.3 heads fully assembled from Texas Speed for ~$1300/pair. They flow 300 CFM, 58cc chambers, and come fully assembled.

For 12:1 compression and a carb, I would recommend something on a 110 LSA. The GM ASA cam would be a decent shelf-cam for this combo if you used stock heads.

If you do get aftermarket or PRC heads, I would probably use this cam:
https://www.summitracing.com/parts/h...make/chevrolet

Yes, there are better cams out there. But for an in-stock cam at only $360, I would go this route (because I'm a cheap ***).

 

I've got a used set of gen 3 rods. Still on the wall about the heads. Could just mill the 799 and mill them with these wiseco. Then how much lsa? I'll have to calculate again with those junkyard pistons but 11.1 or whatever would be fine and I can run the Gm cam u mentioned

 

Thanks for all the help btw... idk how I didn't find those pistons lol. I love these forums

 

You would have to mill the 799s Just to get the same compression you would with stock 5.3 heads.

 

Aren't 799's stock on late 5.3's?

 

Stock 706 are prone to cracking.. actually the ones I have are cracked... 799 is stock 2005 and up I believe. Maybe 04 and up. So I can get them cheap and stock spring is good under 600 lift. So I hear anyway. The Gm Asa cam with 799s milled down will get this build done on the cheap. I'm thinkin of starting a 6.0 after this... I'll have same invested in a 5.3 by boring it to 5.7 as I can get a 6.0 block lol. I just jumped into all of this foolishly.

 

799 heads have larger chambers than 706/862 heads, and will lower compression. The stock springs are only good to 550 or so lift.

The 706 heads that were prone to cracking were the early ones with a battery symbol on them under the rockers. Later ones and 862s are fine.

 

Ok. So either set needs work. Which gives more power? All I read about is people ditching the 706 or 862 heads. I lose compression with 799 and lose flow with 706..

 

You want 12:1 and "lots of spray". Why are you so focused on using OEM castings?

 

Maybe I thought it'd be cool to make a 12.1 compression because my uncle was always talking about his old 454...then I got read through what everyone has to say... losing head flow to gain compression seems unwise but spending the money to mill heads to gain maybe 10-20 horse also seems dumb. More flow would help at the strip compared to the 706 heads having a better mid range but falling on its face.. . I have another set of 706 which i picked up today on anither lm7 that I just need to search for that battery casting... best bet if they aren't contenders is aftermarket which won't be too bad if I don't need to get rods

 

I would get Gen 4 5.3 rods and pistons, .040 gasket, and either go cheap and get some 799 or 243 heads and mill them, or just look for a used set of PRC 2.5 5.3 heads, they are less than $1000 used and there was a couple of sets in the classifieds here.

 

It's taken me twenty minutes to reply because I made my account with the Facebook login and it never keeps me logged in and when I go back to this page after logging in it always logs me back out or stops responding... anyway I like the way u think. I'll get to work but been meaning to ask if this cam is worth anything..

http://www.ebay.com/itm/used-gm-ls-l...xUeOPV&vxp=mtr

 

Stock LS7 camshaft is pretty bad for what you want.

Carbs like a narrow LSA, as does high compression.

 

Even with a 300 shot of nitrous?

 

The nitrous is the only reason I wouldn't go for a 108 LSA on a high compression carb setup.

 

Well getting a set of milled 799 heads is taken care of... now to order pistons. I kinda liked the dome ones posted earlier but any idea what my ptv would be? Heads milled .030, .040 gasket.. the cam u suggested. I could always run gen 4 pistons tho

 

With the aftermarket forged pistons, you really don't have to worry about PTV. They usually have pretty generous valve reliefs, especially Wiseco's.