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How much HP can this head support?

General engine tech -- Drag Racing to Circle Track

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ClassAct
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Re: How much HP can this head support?

Post by ClassAct »

Krooser wrote: Tue Sep 14, 2021 12:12 am
mag2555 wrote: Mon Sep 13, 2021 4:44 pm So you say they are mildly ported and attaining 294 cfm up from the stock 240 or so?
At what lift is the 294 cfm coming in at?
Is it in the range of the lift of either of those two Cams you have?
.600 lift before they laid over. If I got those intake ports squared off I have been told they would do 330 cfm.

Had an old friend flow them since the PO didn't remember what they did. He has a pretty honest flow bench (and dyno) and does not sugar coat the numbers to make the customer feel better.

The wonky pushrod angles on the SBM heads cost you a bit of lift but not so much with the W2 heads which have the pushrods moved off center. But I will use 3/8" pushrods to keep as much as I can.

This engine did 575 HP when first built back in '93. Ran about 18 nights and was stored until '07 when it was put into a dirt A mod and was run cold on alky and it ultimately took out two rod bearings, the crank, four pistons three rods and one cylinder. I fixed it and it's ready to be assembled after I do some oiling modifications.
Making them square is a shit ton of work and it’s maybe 10 CFM. There is more to making power than what a flow bench says. CFM is near the bottom of what matters.
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Re: How much HP can this head support?

Post by Krooser »

ClassAct wrote: Tue Sep 14, 2021 12:47 pm
Krooser wrote: Tue Sep 14, 2021 12:12 am
mag2555 wrote: Mon Sep 13, 2021 4:44 pm So you say they are mildly ported and attaining 294 cfm up from the stock 240 or so?
At what lift is the 294 cfm coming in at?
Is it in the range of the lift of either of those two Cams you have?
.600 lift before they laid over. If I got those intake ports squared off I have been told they would do 330 cfm.

Had an old friend flow them since the PO didn't remember what they did. He has a pretty honest flow bench (and dyno) and does not sugar coat the numbers to make the customer feel better.

The wonky pushrod angles on the SBM heads cost you a bit of lift but not so much with the W2 heads which have the pushrods moved off center. But I will use 3/8" pushrods to keep as much as I can.

This engine did 575 HP when first built back in '93. Ran about 18 nights and was stored until '07 when it was put into a dirt A mod and was run cold on alky and it ultimately took out two rod bearings, the crank, four pistons three rods and one cylinder. I fixed it and it's ready to be assembled after I do some oiling modifications.
Making them square is a shit ton of work and it’s maybe 10 CFM. There is more to making power than what a flow bench says. CFM is near the bottom of what matters.
I kind of feel the flow # allows you to have a target HP that you may hit if all is right. The more cfm the more potential....
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Re: How much HP can this head support?

Post by ClassAct »

Krooser wrote: Tue Sep 14, 2021 1:46 pm
ClassAct wrote: Tue Sep 14, 2021 12:47 pm
Krooser wrote: Tue Sep 14, 2021 12:12 am

.600 lift before they laid over. If I got those intake ports squared off I have been told they would do 330 cfm.

Had an old friend flow them since the PO didn't remember what they did. He has a pretty honest flow bench (and dyno) and does not sugar coat the numbers to make the customer feel better.

The wonky pushrod angles on the SBM heads cost you a bit of lift but not so much with the W2 heads which have the pushrods moved off center. But I will use 3/8" pushrods to keep as much as I can.

This engine did 575 HP when first built back in '93. Ran about 18 nights and was stored until '07 when it was put into a dirt A mod and was run cold on alky and it ultimately took out two rod bearings, the crank, four pistons three rods and one cylinder. I fixed it and it's ready to be assembled after I do some oiling modifications.
Making them square is a shit ton of work and it’s maybe 10 CFM. There is more to making power than what a flow bench says. CFM is near the bottom of what matters.
I kind of feel the flow # allows you to have a target HP that you may hit if all is right. The more cfm the more potential....


I’ve lost flow and made more power many times. That port NEEDS a 2.08 valve. And if the flow never goes over 290 it will still make more power. The flow bench and flow numbers are not the best metric for determining power potential of a given cylinder head.
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Re: How much HP can this head support?

Post by 408swinger »

mag2555 wrote: Mon Sep 13, 2021 4:44 pm So you say they are mildly ported and attaining 294 cfm up from the stock 240 or so?
At what lift is the 294 cfm coming in at?
Is it in the range of the lift of either of those two Cams you have?
Thats about right for a good mild port job on W2s.
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Re: How much HP can this head support?

Post by Krooser »

ClassAct wrote: Tue Sep 14, 2021 5:51 pm
Krooser wrote: Tue Sep 14, 2021 1:46 pm
ClassAct wrote: Tue Sep 14, 2021 12:47 pm

Making them square is a shit ton of work and it’s maybe 10 CFM. There is more to making power than what a flow bench says. CFM is near the bottom of what matters.
I kind of feel the flow # allows you to have a target HP that you may hit if all is right. The more cfm the more potential....


I’ve lost flow and made more power many times. That port NEEDS a 2.08 valve. And if the flow never goes over 290 it will still make more power. The flow bench and flow numbers are not the best metric for determining power potential of a given cylinder head.
I agree with that.

Many of todays racers buy their engines complete and dont have any idea whats inside. But talking to some engine builders I have found they screw SBC's together with "spec" Brodix heads with less flow than my ,W-2's but with cams with way more lift than my two.

My buddy had a .650 lift roller in his small block using those spec heads that flow about 270 iirc. Then the cam guys tell me I need a .555 cam. Confusing info for a senior citizen!!!
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Re: How much HP can this head support?

Post by Walter R. Malik »

Krooser wrote: Sun Sep 12, 2021 2:23 pm I have a set of W-2 Mopar heads that flow 294 intake/180 exhaust. 13-1/alky/7200-7500 rpm/M-1 single plane/850 BG.

How many horses with a head like that support in an endurance application. I will have it dyno's but just curious.
With a 368 drag race engine on gasoline, just under 13/1 compression our customer made 663 horsepower at 7,800 RPM with a Dominator carb on a Holley intake.

The heads flowed about those exact numbers except they had 2.055" intakes and 1.625" exhausts; cam was 278/286; .645" valve lift.
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Re: How much HP can this head support?

Post by SpeierRacingHeads »

I did a set for Clint, car was featured in Mopar Muscle around 3/19.. It regularly runs 10.4's @ 128 mph and drives it everywhere. Full interior, all steel.

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Re: How much HP can this head support?

Post by bob460 »

SpeierRacingHeads wrote: Wed Sep 15, 2021 4:07 pm I did a set for Clint, car was featured in Mopar Muscle around 3/19.. It regularly runs 10.4's @ 128 mph and drives it everywhere. Full interior, all steel.

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Was it ever dynoed?
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Re: How much HP can this head support?

Post by mt-engines »

The cfm could make 400hp or 650hp... there is more to it than just raw flow numbers..

600hp in a 3100lb car should go low 10s.
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