b005td

iTrader: (9)

try to see if i spent my money wisely
thanks

Stang's Bane

iTrader: (22)

Looks like they were flowed at MTI, and the numbers look good. Do you know what the runner volume is??

Studytime

iTrader: (15)

I'm going to have to disagree with that. I don't think they are that wonderful. The last set of 2.00"-valved 853s I ported that went on a flow bench flowed 210 cfm @ .300" (yours are at 189cfm). Granted yours are flowing ~300 @ .600" lift, but low-lift numbers look soft on these.

There probably is an application for these heads, but for the steet I'd try and snag something with some better low-lift numbers. Also, with this being said, keep in mind that flow numbers aren't the end-all for a cylinder head comparison. There are too many variables that don't easily show up on a bench, and there is the possibility of operator error. If the bench operator doesn't get the geometry right for the valve opening then the numbers will be messed up.

Ben T.

Patrick G

iTrader: (14)

Surprisingly, your best performance comes from airflow in the .300-.500" range. The numbers at .300" and .400" are especially important. For this reason, I would say your porter was trying to impress you with a high peak number, but the real world performance on the heads is going to be average at best.

For what it's worth, the top ported cylinder heads (TFS, ETP, AFR) flow in this range on a 3.900" bore:

.200" 150-158
.300" 217-220
.400" 261-264

Look at yours. They're down about 20-25 cfm. This is a case where spending more will get you more.

Stang's Bane

iTrader: (22)

Look at the high-lift numbers, they keep climbing. i just glanced at a couple of things and didn't compare any numbers, so I will agree with you. However these heads may have been worked for a solid roller or something.

Studytime

iTrader: (15)

Even if worked for a solid-roller with .650" + of lift, there is still power to be had with stronger midlift numbers, but I do see where you are coming from. Keep in mind the fact that you see peak lift once, but mid and low lifts happen twice for each valve event.

The best way to evaluate these heads (if the quality of port work is up to par) is to bolt them on and go racing. Let that have the final say in how they perform.

I'd take a cylinder head that has strong low-lift and midlift numbers ANY day over a head with just good peak lift numbers. I'd even perfer it if the port did go on to backup at, say, .600".

I'd especially pick mid & low lift numbers over peak when using the LS6 intake.

Ben T.

Stang's Bane

iTrader: (22)

Amen, to the take it to the track. Flow bench numbers don't win races

Patrick G

iTrader: (14)

That's not the advice he was looking for. He's wanting to find out if his heads are going to be competitive based on their flow numbers. After seeing solid correlation between mid-lift flow numbers and track/dyno performance, I can say that while these heads are a step up from stock, they lag pretty far behind the better offerings currently on the market. Telling him to take it to the track is like telling him to wait until he's spent all of his hard earned money until he finds out he's a few car lengths behind where he could have been.

Stang's Bane

iTrader: (22)

All I was saying is that just looking at flow bench numbers is only part of the story behind a good set of heads. For all we know he could be using a big solid roller and a single plane intake. He also may have paid $500 for them, so he did get a good deal if that was the case. Like you said you get what you pay for most of the time.

Studytime

iTrader: (15)

Patrick, I already stated I would get something with better lowflow numbers. I was trying to be polite if for his sake.

Don't forget the as-cast Dart 205s break the correlation you just mentioned. They have poor low flow numbers, actually backup at like .550" lift, but make really good power.

Ben T.

Patrick G

iTrader: (14)

Ben, I totally agreed with the two posts of yours above. And for what it's worth, the Dart 205s I've seen had above average low and mid-lift flow due to the excellent valve jobs. This is the main reason why they make big power (since the higher lift flow numbers are average). I feel like we're saying the same thing.

I'm a fan of the Dart heads.

Spellbound

Looks like he already bought them.

Is there anything he could do with cam selection to help out?

b005td

iTrader: (9)

thx so much for the advise guys

actually i havent got them yet, typo there
from the info here, looks like i wont be getting those heads, thx guys, may be get some TSP / AFR / Dart down the road

i already have a TR230 / 224 cam
i should have put that in my sig or something

edit : but if anybody wanna get these heads for $900 pm me, i'll get u contact info of the seller

Studytime

iTrader: (15)

Patrick,

My set was certainly not above average or even just plain ole average.

Here's a thread I made about them,

https://ls1tech.com/forums/generation-iii-internal-engine/513445-had-set-dart-205s-bench-morning.html

The VJ was real pretty and actually blended in by hand with a carbide cutter (not a 5-axis CNC like Dart claims), but still they flowed mediocre. These heads showed a 29rwhp gain over LS6 heads on a 230* cam. That was with a F.A.S.T. 90/90 intake. I still scratch my head on how they make the power number that they do.

I agree we're making some of the same points as well.

Ben T.

Stang's Bane

iTrader: (22)

It just goes to show you that the flow bench doesn't mean everything.

Studytime

iTrader: (15)

...and PRC's 237cc intake runner LS6 heads that still make good low-speed torque, GM offering 260cc L92 heads on a freakin' heavy SUV. Some of this stuff makes me scratch my head. You think you start figuring it out, and then this comes along. Repeating the term "flow quality" makes me feel better about it although I don't fully understand.

Ben T.

Stang's Bane

iTrader: (22)

So true, so true..

b005td

iTrader: (9)

damn than what kinda heads should i get

Stang's Bane

iTrader: (22)

How much money do you have and how fast do you want to go??

b005td

iTrader: (9)

what i meant is if that doesnt really tell everything how else can i determine if the head is worth buying or not

there a guy here in town saying he got a set of ported / reworked 5.3 heads and will sell for 1100 and he said the flow numbers are exactly same as the AFR 205. i know that the guy that did the rework was very reputable in town. but what else i need to look for ?