As we all know, flow numbers aren't everything, but they are meaningful. That being said look at these and let's discuss them. I'm not saying what head it is or who built it and tested them. I will say these are intended for a 390-430 ci in engine.

I .200 160 E 122
I .300 255 E 170
I .400 330 E 213
I .500 371 E 240
I .600 390 E 254
I .700 394 E 261

If those are Small Block Chevy they are really good heads. Probably high end recent 18*

Not SBC

I would think enough compression (12.5:1 & up) those flow numbers seem to be on par with some of the LS3/LS7 aftermarket stuff and those are making around 650-750 or more hp 376-427ci.

I think you may get as many opinions as participants – lol.
In what way will they be used? Target RPM band?, fuel choice?, N/A or ?, and are you primarily interested in crankshaft numbers or ET slips – and obviously if its ET slips, and you have to plan around fixed conditions (car weight/leave point/trans type/# of gears ….etc) lots more info needed.

And if its not SM GM….must be a mopar BB – LOL!

About to sign off for the day , may not be back until sunday or monday morning, follow up then.

Not BB Mopar.

Not LS

CR 13.5:1, 6000-7400 RPM, race gas

Bracket car 3200#, PG, 950 cfm carb.

quote:

Originally posted by "The Bender":
As we all know, flow numbers aren't everything, but they are meaningful. That being said look at these and let's discuss them.

I disagree, they are meaningless as to an indication of how a given car/combo will perform on the track. The larger the port the more air it will flow. You want the greatest flow from the smallest port when comparing/considering heads and mid lift flow not peak is everything.

All advertised big flow numbers are good for us selling heads to the naive and misinformed.

Stock head CC for this engine are 190, the heads I gave the flow #'s for are 205 CC. So, not a bunch bigger, volume wise.......

Stock intake valve size 2.06, these heads have a 2.165 valve

Heads with better flow numbers will almost always perform better on the track, unless the original heads are too large already. In this case the original heads are stock heads and designed for a daily driver production car/engine with 50 less cu in than the engine these heads are going on, not to mention this engine will be a race engine with a higher RPM operating range than the stock engine.

Your goals should be stated but here's some info for you:

- They should support up to 725 to 775 HP (assumes all other parts are sized accordingly)
- the E/I ratio is about 65% so it will want more duration on the EX side for your cam.
- Port air speed is another key factor missing
- Your carb size is a good size for the 700HP range
-Can't comment on your target RPM until you list the CID of the motor.

quote:

Originally posted by "The Bender":
Stock head CC for this engine are 190, the heads I gave the flow #'s for are 205 CC. So, not a bunch bigger, volume wise.......

Stock intake valve size 2.06, these heads have a 2.165 valve

Heads with better flow numbers will almost always perform better on the track, unless the original heads are too large already. In this case the original heads are stock heads and designed for a daily driver production car/engine with 50 less cu in than the engine these heads are going on, not to mention this engine will be a race engine with a higher RPM operating range than the stock engine.

Ed & The Bender

Air speed matters, too much and too little will hurt performance. Need to pay attention to increasing the intake valve size on a small port head, the flow bench can lie here! If the larger valve increases air speed too much by increasing air flow, the engine will not produce the power that the flow number indicates! In fact it will make less power than the same head with the smaller valve!!! Once the intake port goes into choke velocity it's over! This will occur sooner with the larger intake valve and therefore make less HP!!

quote:

Originally posted by TOP38:
Your goals should be stated but here's some info for you:

- They should support up to 725 to 775 HP (assumes all other parts are sized accordingly)
- the E/I ratio is about 65% so it will want more duration on the EX side for your cam.
- Port air speed is another key factor missing
- Your carb size is a good size for the 700HP range
-Can't comment on your target RPM until you list the CID of the motor.

420"

Cam has 10° more duration on the exhaust side @.050

This head has a short intake port, so 205cc is not really small in this case

quote:

Originally posted by "The Bender":

quote:

Originally posted by TOP38:
Your goals should be stated but here's some info for you:

- They should support up to 725 to 775 HP (assumes all other parts are sized accordingly)
- the E/I ratio is about 65% so it will want more duration on the EX side for your cam.
- Port air speed is another key factor missing
- Your carb size is a good size for the 700HP range
-Can't comment on your target RPM until you list the CID of the motor.

420"

Cam has 10° more duration on the exhaust side @.050

This head has a short intake port, so 205cc is not really small in this case

I was just gonna ask you that, what's the ports average CSA? CC's are good to know once you know what heads your talking about, but a blind number is meaningless, cross sectional area is what really counts.

quote:

Originally posted by TOP38:

quote:

Originally posted by "The Bender":

quote:

Originally posted by TOP38:
Your goals should be stated but here's some info for you:

- They should support up to 725 to 775 HP (assumes all other parts are sized accordingly)
- the E/I ratio is about 65% so it will want more duration on the EX side for your cam.
- Port air speed is another key factor missing
- Your carb size is a good size for the 700HP range
-Can't comment on your target RPM until you list the CID of the motor.

420"

Cam has 10° more duration on the exhaust side @.050

This head has a short intake port, so 205cc is not really small in this case

I was just gonna ask you that, what's the ports average CSA? CC's are good to know once you know what heads your talking about, but a blind number is meaningless, cross sectional area is what really counts.

That I do not know.

What I can tell you is that the port measures 2.00x1.875 at the gasket surface and does not narrow down on it's way to the valve.

quote:

Originally posted by "The Bender":

quote:

Originally posted by TOP38:

quote:

Originally posted by "The Bender":

quote:

Originally posted by TOP38:
Your goals should be stated but here's some info for you:

- They should support up to 725 to 775 HP (assumes all other parts are sized accordingly)
- the E/I ratio is about 65% so it will want more duration on the EX side for your cam.
- Port air speed is another key factor missing
- Your carb size is a good size for the 700HP range
-Can't comment on your target RPM until you list the CID of the motor.

420"

Cam has 10° more duration on the exhaust side @.050

This head has a short intake port, so 205cc is not really small in this case

I was just gonna ask you that, what's the ports average CSA? CC's are good to know once you know what heads your talking about, but a blind number is meaningless, cross sectional area is what really counts.

That I do not know.

What I can tell you is that the port measures 2.00x1.875 at the gasket surface and does not narrow down on it's way to the valve.

Any idea of the port centerline length? Or you can list the head and I may have that.. PM me if you want to keep it a secret! LOL

I will take a look at the numbers with the info you listed and get back to you

PM me your cell # and I'll send you a good picture of the port.

It is not a common head, I doubt you'd have any info on it.........

Dam they look like Profiler BBC 174 320cc's but they don't have the rest of the criteria.

Lift Intake CFM Exh CFM % Exh/Int
0.200 164 129 79%
0.300 228 162 71%
0.400 288 198 69%
0.500 337 235 70%
0.600 380 255 67%
0.700 395 265 67%

https://www.profilerperformanc...24-degree-heads.html

quote:

Originally posted by 69427:
Dam they look like Profiler BBC 174 320cc's but they don't have the rest of the criteria.

Lift Intake CFM Exh CFM % Exh/Int
0.200 164 129 79%
0.300 228 162 71%
0.400 288 198 69%
0.500 337 235 70%
0.600 380 255 67%
0.700 395 265 67%

https://www.profilerperformanc...24-degree-heads.html

Not even close.....LOL

I'm confused what the question is here.

I personally like flow numbers. They are one part of the overall description of how a head works. You shouldn't look at the flow by itself of course. But it certainly is not meaningless. For a combo that needs more flow, I would always prefer a lazy port that flows really well to a tiny port that flows very little. Some drag applications can be very very forgiving when it comes to port size, since many have a very narrow operating band. My current SBC ports are larger than ideal for the flow they have. But with 7000 rpm stall, 7600 shift, and 8100 finish line......the combo really didn't care about the extra port volume. That's not to make the equally ignorant statement that port volume doesn't matter. It all needs to be taken into consideration.

quote:

Originally posted by "The Bender":
PM me your cell # and I'll send you a good picture of the port.

It is not a common head, I doubt you'd have any info on it.........

Making a few assumptions based on the valve size and port entry dimensions the air speed should be OK. Unless there is a sizeable push rod pinch in the port, the ports throat just below the valve should be the smallest CSA which is what you want. At 88% of the valve OD, your average air speed here is around 340 FPS using the head flow data listed. This number is also higher then it would be is the intake and carb or TB where also mounted on the head during the flow test as the actual flow through the intake system will reduce total air flow (CFM) readings. How much depends mostly on the intake used.

So what are your target goals for this combo?

PM also on its way.

quote:

Originally posted by "The Bender":
Not even close.....LOL

I figured as much, I just thru a dart at it.