LS6 Z28

iTrader: (4)

Recently I have been looking at AFR 205cc LS1 Cylinder Heads and had a question about the number. I have stock ls6 heads and I know from researching the 205's flow better but what does the number(205) represent? If the number is bigger does that mean they flow more?

HWI

iTrader: (2)

Intake runner size. Running a larger intake runner size, 225cc for example, may hurt your low end, but will enable you to spin to a higher rpm without starving the engine of air. For a solid street car looking for under the curve power I think 205cc heads would be a good bet, though a lot of people run 215cc Trick Flows with good success also.

RE AND CHERYL

iTrader: (31)

A head that flows really high numbers can quite often not perform as well as one might expect because the many times a trade off of high lift flow is low midlift flow. For a street driven car that rarely sees high RPM operation a midsize intake runner in the 195-205cc range is usually best. For a street driven car a slightly smaller port with good high velocity ports is better than heads with masive ports that flow like gang busters.

I'd probably just get your LS6 heads ported.

Re'

LS6 Z28

iTrader: (4)

would porting my ls6 heads be cheaper in the long run and worth it over just buying say, AFR 205cc heads?

blk/slvr02ss

iTrader: (21)

I would think so unless your going to spent $2000 worth of work on the LS-6 heads but you should spend half of that to get better flow out of them.

LS6 Z28

iTrader: (4)

Would I have to put in more high performance valve springs and etc.? Also if I port my LS6 heads, will they flow as well as the 205cc? Which will have more power?

blk/slvr02ss

iTrader: (21)

What the guys are trying to say is you will loose on bottom end w/ the AFR's but will gain @ high RPM'S and if thats what your shooting for then the AFR's will be fine but if you want to have bottom end ,Mid range and do not want to rev high then doing some work to the LS-6 heads will be fine instead of spending the extra on the AFR's.What you want to do w/ them will be up to you.Whoever you have do the work will let you know how far do you want to go w/ the LS-6 heads.

02*C5

iTrader: (1)

I know a lot of guys running 400+ and up to 500 on ported LS6 heads. A good head and port job will run around 1600 with new valves and springs to include head milling. The valves that the LS6 heads bring are phenomenal. If you want to upgrade the valves but stay with the hallow valve set up Ferrea sells them. Patriot Gold Extreme springs work great on the LS1/LS6 heads. My head guy always says if your going to do a job do it 100% or don't do it at all. Oh and the one thing every one seems never to talk about the gaskets head bolts and upgrade the crank bolts is the way to go.

nick1ta

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redtail2426

iTrader: (10)

i have not seen a single good post here yet.try porting in the internal engine section,you will probably find the answers you are looking for.If you cant afford the afr's,then buy them,they are worth it.They will provide you with a small,high efficient port which will provide better low end,midrange,and probably top end,then 95% of ported ls6 heads.It all depends on your goals for the car,and the type of action it will see,street,track,autocross.

ramdaspadhye

iTrader: (3)

Have your heads CNC'ed by a reputable shop. Usually runs between 600 and 1000 depending from what I've heard. they will CNC and include a flow sheet (good shops will, that is) and if they're the same as the AFR's for a given lift, then it's the same!

corvet786c

iTrader: (6)

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WHEN IT COMES TO HEADS DONT PLAY AROUND WITH JUNK. GET THE BEST IMO AFR 205 milled to 62cc is very good.