quiet_storm98

iTrader: (48)

There is alot of debate about cylinder heads and which castings produce the best results.. however it is well known that the ls6 heads consistently flow better then the ls1 or 5.3 heads but for some reason alot of people are under the impression that ported ls1 heads are worthless. So i got a pair of each of the heads and had them flowbenched to see the results. All of the heads were done by companies that are fairly well known around the ls community and all the heads were claimed to flow over 300 cfm. All the heads were flowed on the same bench using the same flow method as well. The result was that all the heads flowed pretty well

ported ls1 head with 2.02 & 1.57 valves (advertised as flowing 305 cfm@.600)

intake.......exhaust
.100 65 ....... 54
.200 134 ....... 103
.300 197 ....... 146
.400 242 ....... 176
.500 278 ....... 199
.600 300 ....... 213

ported 5.3 head with 2.02 & 1.57(advertised as flowing over 310cfm@.600)

intake.......exhaust
.100 66 ....... 54
.200 134 ....... 109
.300 198 ....... 147
.400 245 ....... 185
.500 279 ....... 210
.600 296 ....... 222

ported ls6 head with 2.02 & 1.550(advertised as flowing 307cfm@.600)

intake.......exhaust
.100 69 ....... 60
.200 137 ....... 121
.300 208 ....... 161
.400 258 ....... 195
.500 290 ....... 214
.600 306 ....... 223

as you can see the ls6 head outflowed the other heads pretty significantly throughout the flow range. The ls1 and 5.3 head were basically equal and the LS1 head actually had a slightly smaller runner then the 5.3 head (222cc vs 225cc). Hope these results help some people out.

itsjustaSB

iTrader: (13)

nice real world numbers should help alota people out right now

chevynation

iTrader: (8)

Are these heads all from the same porter?

quiet_storm98

iTrader: (48)

no they aren't all from the same place but all the companys are fairly well known places when it comes to porting ls1 heads

edcmat-l1

iTrader: (10)

Were they CNC ported, or hand ported? I tend to shy away from hand ported heads due to possibilities of inconsistency. For me CNC is the only way to go. Unless I'm using a local guy I know personally.

quiet_storm98

iTrader: (48)

the ls1 head was handported and all the ports were flowed and were just as consistent as the cnc'd heads

StripedZebra

iTrader: (6)

Now when you puttin them up for sale

quiet_storm98

iTrader: (48)

lol only the 5.3 heads were mine..i may be selling them though if you are interested. The ls1 heads are also for sell. By the way the combustion chambers were also measured on the heads, the ls1's had 64cc combustion chambers while the 5.3 and ls6 had 60cc's

Beaflag VonRathburg

iTrader: (176)

This will be a good thread to point all the, "Should I spend time porting my stock heads" threads.

quiet_storm98

iTrader: (48)

exactly

gtorep

iTrader: (18)

Good job bro.

BOWTIE

Nice info, but it would help a little more if we knew who the porters were and when these heads were ported, since many of the cnc programs have changed over the years.

PREDATOR-Z

That would start a nice internet war with all kind of excuses

H.Veras

Interesting, I thought the LS6 heads were far superior than the LS1, but even though they are better the difference is not that much.

Formulated

iTrader: (16)

What was the port volume on the LS6 head? You mentioned 222cc and 225cc for the LS1 (I presume 241 casting) and the 5.3 head respectively. Also, do you know what valves are in each head? 2.02 on the intake is good, but what about details like brand or if there is a back cut on the valve head. Looking at the data I wonder if the LS6 head by any chance had nicer valves than the other two.

Thanks for posting up the info. It's a great reference.

quiet_storm98

iTrader: (48)

thats why i didn't post the company names

quiet_storm98

iTrader: (48)

the port volume wasn't measured on the ls6 head but it was probably around 225cc's just like the other heads. I know the ls1 head had manley valves and the 5.3 heads had ferrera valves..not sure what valves were in the 243 head but i dont think they were any better, as a matter of fact the ls6 head had a smaller exhaust valve then the other two.

bjamick

iTrader: (31)

The LS6s are definitely better. I mean look at .200-.500 the LS6 heads just about rape them in that category. Flow at .600 means jack **** when you dont have an intake to flow that much air anyways .. I've got ported 5.3s also that ill be putting on a bench soon and maybe whenever i get that done ill post my results.

JPH

iTrader: (2)

nice work quietstorm. So what heads you gonna go with, LS6 i presume?

quiet_storm98

iTrader: (48)

yeah im thinking about going with some ls6's but i would need to sell the ones i have first..i may just go ahead and sell them for pretty cheap