Generation IV Internal Engine - Happy with my heads *added flow numbers/stall point

Just got the flow numbers from my head porter and they are great even being 100* and humid in their shop(flow bench was just checked too). @.600in lift intake 351 ex. 244, and the numbers are even better down low. I was worried due to all the negative remarks I have heard about screwing these heads up. He has always built me badass setups, guess I shouldn't have sweated it. Can't wait to get the bad boy together and on the road!!

what heads? in the SS?

Who is the head guy? What heads? Before #'s?

what heads? in the SS?
823's, and yes I the SS

Who is the head guy? What heads? Before #'s?

He's not a sponsor, stock they flowed 319 /215 @ .600

Where do they stall? Is there a before after number as well?

Very nice improvement.

I'm just curious as I had Chris Frank prep a set of heads, with similar before & after improvements. Very real gains from .400 lift. The stall speed moved up as well, my cam is in the .650 area.

what do you mean by stall speed?

Where do they stop picking up flow, what lift.

This is referred to as stall.

Never new that term, learn something new everyday. I don't really see where there is a stall.

w/o pipe / pipe
240/244 230/237

before
in. ex
.200
.200 144 115
.300 211 160
.400 269 193
.450 290 201
.500 301 208
.550 314 211
.600 321 216
.650 330 219


After

.200 144 121
.300 220 169
.400 279 198
.450 297 205
.500 323 216
.550 337 238
.600 351 244
.650 359 249

If your porter or you would have them flowed up to .800 or higher you would be able to see where the port begins to stall.

Up to .650 lift it will be hard to see where that happens as most good head porters like you have will be able to create good flow numbers in the region you have listed as that is where you're most likely to be in that lift range with a hydraulic roller.

He has already bagged them for me to pick them up, but I'll ask to see if he will put them back on the flow bench. What difference would it make to me since my cam is way under .650 lift? Will stall come in to play due to large duration?

For you theres no point in knowing. I bekieve he was just making the point that had the flow continued on you would see the stall area better

Nice they are picking up @ lower lift. Are you going to dyno & re tune? It will need a sizable amount of fuel.

My heads started as TF 235's rough cut, so the runner is 10-12 smaller than off the shelf. The finished version is 235-237 with 31 cfm better than what I took off.

They stall @ .700

For you theres no point in knowing. I bekieve he was just making the point that had the flow continued on you would see the stall area better

Thanks for grabbing that answer for me!;)

No point in knowing, for what you have you have a good set of heads. No need to know what could have been.

You guys have me curious now, so I will ask him to flow them for comparison. Thanks for all the information.

Your head guy may already know the answer, it's a topic that got me going on why my motor was not meeting expectation's. A thread on this forum perked my interest with a discussion involving a couple of guy's from Australia.

For other reasons my car was sitting with headers & intake off, so I decided to pull the heads. The cylinder heads were not going to get me to my expected power level.

What are your expectations and what are you making

I'm 30 rw & 30 ft lbs below my original goal. Hoping the additional 31 cfm is going to get me there. The heads will be the only change, so a more than fair test. No that's not true the Fast 102 had problems as well.

All in all it will be interesting test.

the heads stall at just over 700 C F M.
.700 in 365 ex 254
.750 in 345 ex 257

Nice.

You mean they stall just over .700 lift

Nice.

You mean the stall just over .700 lift yes, but exhaust us still flowing

You may need more than just heads to meet your goals. Whats your setup? A cam change may do you good with better flowing heads, and a chance to switch to a better grind as well. That could possibly put you slightly beyond your goals.

You may need more than just heads to meet your goals. Whats your setup? A cam change may do you good with better flowing heads, and a chance to switch to a better grind as well. That could possibly put you slightly beyond your goals.

I'm guessing this isn't targeted toward me. My expectations aren't numbers, but results at the track.

I figured they would stall around .700 lift as your head ported obviously knew when he was porting them the lift range your cam would be in.

Good job, keep us updated with results.