Dart NEW REVISED SHP SBC Cylinder Heads

[BOOT]

Ps this is what the last dart shp 180 looked like I flowed. It doesn’t look like you old dart head.

Yah you can see the casting is much smoother and that bulged is there unlike my OLD casting. Plus the guide boss isn't machined since it looks like there is no bronze guide yet? Bet my Old 2019 casting flowed worse than yours.

[NewbVetteGuy]

Anyone have any flow bench numbers beyond .500" lift yet, especially for the 200cc heads?
(Just curious.)

Adam

[steve cowan]

Anyone have any flow bench numbers beyond .500" lift yet, especially for the 200cc heads?
(Just curious.)

Adam

Not what you are asking but my ported 180cc out to 203cc went 285cfm @ 0.700" @28".
I have nearly finished 1 x port with my valve job might be a bit bigger than 203cc pinch is 2.27" without blowing through but is very thin.
I have several sets of heads 165 cc - 215 cc they all had stability issues above 0.500" lift,airspeed to fast over SSR usually.

[steve cowan]

Finished a intake port to my liking and wanted to share so I hope Boot does not mind me being on his thread.
Disclaimer- I am not a professional, just a home hobby guy who enjoys drag racing so take my information as you see fit.
My engines are 383sbc were I want peak around 6500 rpm but would like to be able to over rev 1000rpm or so.
You hear all the time where throat should be the smallest area in the port but hard to do on a 23 degree head unless you run a small intake valve but that can limit you depending on application.
Dart 180cc out to 207cc port is 5,45" long
5.45" x 16.387 = 89.30.
207cc / 89.30 = 2.31 average cross section area (CSA)
290 CFM X 2.4 = 696.
696/2.31 = 301 AVG FPS (VELOCITY)
Port measurements -
2.02 valve - 3.11" area includes 0.09" for stem area.
1.81" throat 89.6% of valve 2.48" area
Bowl 1.99" - this is width above valve guide
SSR - 1.90" wide x 1.60" high = 3.04"
Pinch - 1.18" wide x 2.05" high = 2.29" includes radius factored in .
Holley strip dominator intake
Inner runner 3.34" avg csa - 4.380" long
Outer runner 3.45" avg csa - 5.070" long
Plenum
3.70" x 3.80" x 3.70" high.

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[steve cowan]

I probed with pitot as well and took 3 x readings and averaged.
I did flow with intake and 2" open spacer.flow loss was approximately 4% across the range. Around 240 FPS at opening of intake @28" I am able to test up to 45" I am looking for stability across the lift curve and not chasing flow numbers, if I layed down SSR more it would go 300cfm but I will leave it at this stage.
I looked at the as cast numbers from dart for there SHP 200cc head.
I would always purchase a smaller head and size and stabalize for the application.
It seems most as cast heads including CNC stuff still have instability in the port.

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[RevTheory]

I have a set of 180 SHP heads.
What I dislike about them is the top cut transition to the chamber is crap.the chamber is scalloped out alot so to get a better transition I done
35 TC
40 2nd TC
50 seat
60
70 into 90% throat.
Have not had on the bench yet but might
The last photo is the factory valve job

Have you had them on a bench yet? I'm curious about velocity and if they get unhappy and back up somewhere when you start making them move more air.

[steve cowan]

I have a set of 180 SHP heads.
What I dislike about them is the top cut transition to the chamber is crap.the chamber is scalloped out alot so to get a better transition I done
35 TC
40 2nd TC
50 seat
60
70 into 90% throat.
Have not had on the bench yet but might
The last photo is the factory valve job

Have you had them on a bench yet? I'm curious about velocity and if they get unhappy and back up somewhere when you start making them move more air.

Rev,
As above for the older 180 SHP,I won't be buying the new ones as I have 7 sets of heads,more than enough to last me

[BOOT]

Just got my "Replacement NEW SHP head" and could tell right away it's the same head I sent back & Not even been opened LOL

Think I may try to make a quick comparison vid with the ebay heads https://youtu.be/tC3OxGlOrjM before I send it back Again. Most likely they will just refund me completely this time or at least after they Send it to me a 3rd time LOL as that is how it has worked out in the past for this warehouse.

Many years ago after sending me 5 faulty parts in a row they pulled the entire part line and added a fee for my driveway. Heck of a way to thank me for my QC that they didn't do. It was not small flaws either and a fuel system part that they put their own name on.

[BOOT]

Yup it's the same exact head https://youtu.be/YYiNTDRm-7c

But another NEW SHP just showed up!

[RevTheory]

I should have mine tomorrow so we'll see...

[BOOT]

I should have mine tomorrow so we'll see...

Cool, technically I have a pair atm LOL But tomorrow I'll find out if Both are going back.

[1980RS]

I probed with pitot as well and took 3 x readings and averaged.
I did flow with intake and 2" open spacer.flow loss was approximately 4% across the range. Around 240 FPS at opening of intake @28" I am able to test up to 45" I am looking for stability across the lift curve and not chasing flow numbers, if I layed down SSR more it would go 300cfm but I will leave it at this stage.
I looked at the as cast numbers from dart for there SHP 200cc head.
I would always purchase a smaller head and size and stabalize for the application.
It seems most as cast heads including CNC stuff still have instability in the port.20211120_170516.jpg20211120_170407.jpg20211120_151651_resized.jpg20211120_152121.jpg

Steve, is that a 300-25 or a 300-110?

[steve cowan]

I probed with pitot as well and took 3 x readings and averaged.
I did flow with intake and 2" open spacer.flow loss was approximately 4% across the range. Around 240 FPS at opening of intake @28" I am able to test up to 45" I am looking for stability across the lift curve and not chasing flow numbers, if I layed down SSR more it would go 300cfm but I will leave it at this stage.
I looked at the as cast numbers from dart for there SHP 200cc head.
I would always purchase a smaller head and size and stabalize for the application.
It seems most as cast heads including CNC stuff still have instability in the port.20211120_170516.jpg20211120_170407.jpg20211120_151651_resized.jpg20211120_152121.jpg

Steve, is that a 300-25 or a 300-110?

That's a 300-25
Same one I am doing plenum work on,finish today,
I don't have a mill yet but a couple of buddies do so will do different spacers as previously mentioned.
I am spending some time on sizing intake manifolds and porting seems to be a subject not really discussed.
Different length runners,different size and shape at the runner opening, hard to measure correctly.
23 degree intakes are not fun to grind on.

[RevTheory]

I just got mine today and while I haven't pulled any valves yet, these look like a really nice piece. I'm quite impressed.

Thanks for putting these on my radar, BOOT.

[BOOT]

I just got mine today and while I haven't pulled any valves yet, these look like a really nice piece. I'm quite impressed.

Thanks for putting these on my radar, BOOT.

NP I think the New revised head overall is a great head, just I've had other quality issues so far.

How is the deck on both your heads? How are the spark plug holes any of the defects like on mine? Pics in this thread viewtopic.php?f=1&t=64354&p=906157#p906157

You mentioned valves, so I assume you got assembled heads?

My New Bare head has the same issues, deck & this time ALL plug holes.