LS_10

iTrader: (1)

need some feed back thinking of changing from the worked 853's I have to a set of worked and milled 317's...

ZONES89RS

iTrader: (25)

Who worked them? The 317 starts out as a better casting and can flow over 300 cfm with stock valves, the 853 and 241 is not happening without bigger valves.

NemeSS

iTrader: (127)

The 317 share same intake and exhaust port as 243/799
Take the 317 and run

boostdoctor

What does the 317's flow stock?

ZONES89RS

iTrader: (25)

245ish, depending on the flow bench, like 243/799 castings.

LS_10

iTrader: (1)

The 853's had stock valves in them. I have one witha pin hole instead of trying to have it fixed I picked up 2 sets of 317's and am going to have them milled, bowl blended and what not. I am hoping to pick up some more power with them but not sure if I would.

ZONES89RS

iTrader: (25)

You probably will. They flow about 20 extra CFM over the 853/241 stock.

LS_10

iTrader: (1)

That's good news man Thanks! I am so worried I'm going to lose power. I am going to have them cut enough to bump the compression up some more.

ZONES89RS

iTrader: (25)

I see allot of folks going .040 with no issues if that helps.

LS_10

iTrader: (1)

my 853's were cut that much.

speedtigger

iTrader: (16)

The numbers I have see for the 317s have ranged from 255 to 265 cfm. The regular 862 - LS1 head test I have seen have been closer to 240 cfm.

ZONES89RS

iTrader: (25)

Depends on who flows them, this is where i get my info(some):

http://users.erols.com/srweiss/tablehdc.htm#Chevy

853@.600: 227/180

5.3 castings: 223/187

806: 231/173

LS6 on SF600 flow bench: 257/183

Than another advan ind flowbench: 260/183

Then another rating the 243 and 317 casting:236/185 (rather low)

317: 253/184

L92: 322/214


So many variables, but there is tons of data in there, several shops port jobs, stock and aftermarket, great site.

speedtigger

iTrader: (16)

There really is. Way back in the day when flow benches started to become affordable, I was working on some turbo v-6 heads and the guy I brought them to for the "after" testing said to me: "what do you want them to flow?" LOL. That was an eye opener.

ZONES89RS

iTrader: (25)

Man, some shops, i think you can tell which ones, dont have a spark plug or plug of any type in the head when flowing, makes them look like they flow more than they do.

LS_10

iTrader: (1)

this is some good info. I hope with some work they will make a really nice increase

ZONES89RS

iTrader: (25)

One guy i know that owns a shop says he has got 300 cfm from a 243 casting with very little work before, but the 317 and 243/799 are supposed to be identical, they are a very popular head for this reason and are cheap, just the bigger chambers people bitch about, but if you have 400+ cubes, they really work.

NemeSS

iTrader: (127)

My friend that is a SAM graduate got a 243 flowing 310cfm with stock intake valve. He also got a l92 around 368cfm and even shrunk the port. Hes pretty good at grinding. But he work in medical field. Make mo $$

ZONES89RS

iTrader: (25)

Oh yea, 243/799/317 can all hit over 300 with stock valves, it is the other cathedral ports that need the larger pieces.