02_Orange_D1SC

iTrader: (27)

im trying to decide between the two of them im goin to be putting these on a LQ4. id like to get around 11.1 compression with the stock MLS .040 head gaskets which means id have to mill them to around 59cc correct me if im wrong. but my main question is the two heads flow almost the same

5.3 flow 312 intake 223 exhaust @600

ls6 flow 316 intake 226 exhaust @600

and also i plan on running a TSP torqer V.3 cam or something in that range and this is goin in a RCSB 1500 2wd any help would be great.

BrntWS6

iTrader: (7)

I don't know which head matches up better with that cam, but TSP claims a 10rwhp gain with the 2.5 ls6 head.

02_Orange_D1SC

iTrader: (27)

they told me id be better off with the 5.3s cause of the smaller combustion chambers it would boost up my compression but i plan on milling the heads to 59cc weather i get the ls6 heads or the 5.3 heads.

ivan_key

I was wondering the same thing also, I'm stuck between the two

Camaro99SS

iTrader: (4)

The 5.3's have 220cc ports vs the LS6's having ~230cc ports. With the smaller ports, the power band will be alittle lower in the rpm range than with the LS6's. With a heavy truck, you'd be better off with the 5.3's. even if you'd be down maybe 10hp because power under the curve will be alittle better.

Jason

TheLS1Lover

If you are going to mill the heads anyways get the LS6 Heads. They flow better and if you mill them they will also give a bump in CR.

02_Orange_D1SC

iTrader: (27)

so your saying that ill get better TQ which is kinda what i need cause of my heavy pig

BrntWS6

iTrader: (7)

right, why not have both?

BarneyMobile

iTrader: (4)

Keep in mind, milling the heads will decrease flow. The LS6 heads start out with a larger combustion chamber and will require more milling than the 5.3's to get to a 59cc chamber size.

'02 WS6

iTrader: (73)

Runner length is another difference. I vote LS6s.

trans_am7935

iTrader: (15)

i have the 5.3 heads @62cc chambers and used a .040 head gasket on my LS1, and i am making 11.1:1 compression. i dont know why you think you need to run 59cc chambers to get that much compression, unless you dont have flat top pistons. i went 5.3 cause they were 300 cheaper at the time, and i didnt have to mill them. i love them, and if i was gonna spend more then 1200 on a head, then i was gonna go big and get the AFR 210cc heads. the 5.3 heads will be perfect for you, the more milling will drop off airflow, and in the end they will flow just about the same. shorter runners will give you better torque down low as well

'02 WS6

iTrader: (73)

59cc on my LS6 w/ .057 gaskey had mine at 11.1:1 as well. 59cc on a 5.3 head is going to be quite higher than 11:1 and flycutting for PtV clearance would almost be a necessity.

02_Orange_D1SC

iTrader: (27)

The reason I want to mill them to 59cc Is cause i have a lq4 which has dished pistons. Id be somewhere around 10.5 with the 5.3s un milled and somewhere around 10.2 with the ls6 heads unmilled

BarneyMobile

iTrader: (4)

59cc is 59cc no matter what head is used.

SOMbitch

iTrader: (8)

243/799 head everytime IMO.....Not that impressed with my 5.3's...

Theblacknightls1

iTrader: (1)

Do you have prc heads? or stock 5.3L heads? I was very impreesed when i had prc 5.3L heads on my t/a. Had good power down low.

02_Orange_D1SC

iTrader: (27)

did you have the PRC 5.3 heads
what size motor did you have them on

180ls1

iTrader: (4)

id grab the ls6 heads for sure since you are going to mill anyways. Every bit counts since you started to increase cubic inches with the 6.0l and there may be more to come.

Theblacknightls1

iTrader: (1)

my ls1 at the time

SOMbitch

iTrader: (8)

My earlier post was a response to the title of this thread so take from it what you want...

Yes the 5.3's have a smaller chamber but the 5.3 chambers are touched up and mine were 63cc+ so the CR bump is not as much as people think...