InchUp

iTrader: (2)

I'm having a set of 241's port matched int/ex and polished up for an iron block 5.7L build of mine. I'm curious as to the flow increases after a competent machine shop has their way with the 241's. I doubt any milling will be done unless the heads aren't true. I believe the machine shop will replace the valves and valve seats and I picked up a set of LS6 springs to match my DD camshaft, so I was just curious as to what you guys have seen as far as increases. I'm not so much concerned about hp/tq @xxxx RPM's...moreso just bench flow numbers and throttle response, perhaps even VE increases...if any.

Here's what I've found so far as base starting numbers.

Lift......Intake.....Exhaust
0.100.....67...........52
0.200....122...........97
0.300....178..........133
0.400....215..........156
0.500....219..........170
0.550....223..........176
0.600....227..........180

Source: http://www.smokemup.com/tech/ls1.php

02 BLK WS6

iTrader: (11)

For some reason, I thought that the numbers were higher than that??? I have seen numbers on P&P 241 castings approaching 300 on the intake side.

MJD

iTrader: (1)

Work done by Creative Flow Management:

lift in ex

.100 77 65
.200 145 116
.300 199 159
.400 243 190
.500 275 210
.600 285 216

The intake has only the bowl and intake opening done, the runner has not been touched. The exhaust has a full port job as well as the combustion chamber. I am still running stock valves on these and stock compression.

rholdcroft99

iTrader: (2)

i had Lloyd Elliot port my stock 99 TA heads, and reused stock valves
his flow #s
before after
in ex in ex
.100 61 52 72 55
.200 129 99 154 117
.300 189 135 224 158
.400 224 167 270 198
.500 227 181 296 212
.600 227 189 310 225
.700 224 192 316 232

before heads made 379/365. never dynoed, car was totalled. but i ran awsome.

InchUp

iTrader: (2)

Wow those are impressive numbers. Especially .600 310 225! Thanks fellas. Any idea on how throttle response increased? I'm trying to justify spending $350-400 on the P&P, these heads are being bolted to an iron block 5.7L and going into a lifted truck. Was there a noticeable increase in low end torque?

nine-eight

iTrader: (7)

ported heads will help ya everywhere, but the primary thing that will help your throttle response is a correct selection of intake/heads/camshaft with your goal in mind. meaning, if you want torque, get the nice ported heads, something like a stage two at the most, couple it with an ls6 intake, and a low duration wide LSA camshaft for a responsive, torquey motor.

InchUp

iTrader: (2)

I have the iron block 5.7L, 241 heads hopefully soon to be port matched and polished per what the machine shop thinks, LS6 yellow springs, CompCAMS XR265 camshaft (212/218 .522/.529 114lsa off the top of my head 1200-6000rpm use), truck intake and 10.3:1 compression. I think with any "stage 2 this, stage 1.5 that" heads I'd be trading low speed torque and throttle response for top end power. That's what I'm assuming you guys are after, but it's not so good for a big truck like mine, especially since I'm still trying to keep fuel MPG in check. Also with the LS6 intake I would lose even more low speed torque and throttle response due to the larger plenum. The truck intake rocks for what I'm setting my goals for...plus I really don't want to change all my accessories and with my body lift I have the room for the taller intake.

All in all I'm hoping for a nice 360-370hp, 380-390lb-ft of torque, redline around 6000 and a fat, wide torque band from idle-redline. Should do well in my 4L60E auto Sonoma that is lifted 14" taller than stock running 35" tires. Right now the 4.3L V6 sucks.

Thanks for the info guys, I think the gains are worth the expense.