red_04_gto

iTrader: (1)

I am planning on putting these 853s on my 04 gto thats making 400rwhp and 370 tq with home ported TB, 1 3/4" longtubes with 3" mid pipe to 40 series flowmasters, no cats or resinators, underdrive, CAI, 228/230 cam 114 + 1 .589 in 594 ex.

So with all that being said what do you guys think these heads will be worth to me in RWHP. I did an old school conversion and it said something like 460 rwhp but I know thats way too high. I would like to see 440rwhp with a nice jump in TQ as well. SO tell me whats realistic. And are these heads worth my time?

Thanks for any input!!!!


Bench - Super Flow 600 W/O pipe on a 4.00 bore
Head - 853
Valves - Stock
Intake Runners - 220cc
Chamber - 66cc


lift in. ex
.100 73 63
.200 144 103
.300 212 148
.400 256 180
.500 266 200
.600 268 218
.650 270 221

I believe this bench is a little stingy on numbers because a set of LS6 PRC
2.5s did this with 2.04 valves and a 240 runner with a 59 cc chamber.
They are advertised to flow a lot better than this but here are the the numbers w/o pipe and all the same conditions as the first head was flowed under.

lift in ex
.100 73 66
.200 135 116
.300 194 154
.400 247 186
.500 283 205
.600 304 213
.650 306 214

headed-ws6

iTrader: (34)

I would say maybe a soild 20rwhp. the flow numbers arent the best. A budget ls6 head will net you 30-40rwhp depending on the tune. If you havent paid for them i would see about a budget ls6 or 5.3 head.

AU N EGL

I agree. Most PP heads should be around 300 at .600 intake lift

Jantzer98SS

iTrader: (54)

It's not all about the flow numbers. For some reason I have some mid 270 cfm runners that I ported that pushed my heads/cam car to 10.82 back in 03 with a 224/224 .535 .535 cam. The quickest on ls1tech at the time.

Those heads flow far better than a stock LS6 head. If the heads are cheap go with them unless you're trying to set records.

red_04_gto

iTrader: (1)

Bump bump

red_04_gto

iTrader: (1)

any other opinions? Or is 20 rwhp the best I will get out of these? I was also wanting to point out how good the .400 and below flow numbers are, and how they are out flowing the prc 2.5s.

99blancoSS

iTrader: (115)

You have a flow bench providing you with accurate information, it isnt a matter of being stingy. Look at it the right way. You verified flow numnbers with the flow bench you didnt verify the flow bench with advertised numbers. And thats not a dig on anyone, people use different benches and methods and achieve different results.

Irocss85

iTrader: (1)

yay depends on how much the heads are. I ported my own heads on my car and my dads car. there def. alot better then stock, but obviously wouldnt think they would compare to the pro port jobs.
but just by the #s alone, they look fine, and should be somewhere around 20-30rwhp Id guess. but thats just a guess. never know till you bolt them on and did back to back tests.

search my username, compare your head flow charts to mine, then look at my dyno results. if I remember right, I got around 110rwhp on a mustang dyno from stock heads/cam, to my ported heads, mid/large cam, and ported tbody. stock valves in mine too. so thats a small part of my missing flow compared to proported heads #s. it was last year round this time I posted all that stuff.

not the car in my sig, Im talking about what I did to my dads 02 mecham TA.

chris

red_04_gto

iTrader: (1)

Thanks for the input guys, I guess if anything it will make for a good comparison from P&P 853s to bone stock 241s. I already made a 110 rwhp gain with my current mods, without changing the heads. I am hoping this frees up some good airflow so I can make some power, because we all know I need alot of it to move that GTO around lol. I am still open to any input, thanks again.

ibjamin

iTrader: (6)

Those heads flow very nice at .4 lift and below. Should pick up a nice gain with them. Keep the cam mild and you should get a nice broad torque curve.

G.