Ported Dart pro 1 pre platinum

[Carnut1]

I looked at it against the posted ssr and the solder looks the same but the flow is better and the speed across the width of ths ssr is better. I cannot believe how sensitive the ssr is and how big the gains can be when done fairly well. The ssr now actually cuts into the 60 degree valve job cut. These heads were a huge effort and at this point I am pretty happy with them. Now I just need to copy these ports on to the rest! I could really use a donated Serdi! Thanks, Charlie

[mag2555]

Just keep in mind that the whole lenght of the run from the crown of the floor to the end of the chamber makes up the short turn Charlie.

[Strictly Attitude]

Thanks for sharing just read thread from start to finish made my morning.

[Carnut1]

D.V. just let me know he has upgraded his flowbench program and I have a copy. This was free after attending his seminar and this version will be more powerful and he is planning to add more features. Fyi. I hope to download and post up some interesting info on these heads in the next few days. Thanks, Charlie

[randy331]

Now I just need to copy these ports on to the rest!

That's always fun to look forward to.

Likely be a little difference in them. Seems the 2 ports with the pushrod on the left are always a little different than ones with pushrod on the right on 23* SBC heads.

Randy

[Carnut1]

Nearly a full day on D.V. new flowbench program and I am excited to get some results. The problem is with any program garbage in = garbage out so I need to be diligent about measuring and pouring each port for each modification. I have info on port #1 and will post up nice D.V. graphs soon. Port #1 is a gigantic 248 cc so it is much larger than I was estimating due to pain to pour due to bolt hole. Exhaust port a huge 91 cc and still large dip in the flow curve due to turbulence but not noisy. It has been said the quieter exhaust port that flows less will make more power. Totally counter intuitive but certainly possible. I would love some opinions about a 2.08" valve 248cc intake that flows 320.3cfm@.8" lift and a 1.6" valve 91cc exhaust port that flows 222.2 cfm @ .8"lift. Thanks, Charlie

[Carnut1]

0123172034.jpg

stock flow vs. Last flow sheet. Exhaust curve looks like a chunk taken out.

Is it possible that "chunk " taken out of the exhaust flow curve could just be the valve I was using was square edge and short on margin and a large back cut?

[MadBill]

Well a largish margin and top radius is usually recommended for the exhaust valve...

[Carnut1]

0130172026_HDR.jpg

Finally a break with these heads. After flow tests with different margin height valves and different back cuts I dug through my junk pile and found some Manley severe duty valves 2.08/1.6 intake has slight 32 degree back cut and high margin. The exhaust is 1.6" tulip severe duty with a very slight 32 degree back cut and a high square margin. These valves fattened up the midrange of the curves a nice amount! Thanks, Charlie

[Carnut1]

0130172027_HDR.jpg

At this point I am happy with these as far as flow, swirl and velocity which I was worried about when they poured at 248cc! I just need to convince the owner that new valves are a must have!

[Carnut1]

0130172028_HDR.jpg

Comparison to original flows. For those who care the swirl at .7" lift is a nice 3144 rpm, 291 ft/ sec center of the pinch. 340ft/sec cyl wall side ssr, 367ft/sec center ssr, 354 ft/sec center of cyl ssr. Some estimates on port energy are welcome. I am ready to post but need D.V. approval first. Super interesting stuff! Thanks, Charlie

[wyrmrider]

amazing how you can kill a good port with valves that look good but are not

[CGT]

0130172028_HDR.jpg

Comparison to original flows. For those who care the swirl at .7" lift is a nice 3144 rpm, 291 ft/ sec center of the pinch. 340ft/sec cyl wall side ssr, 367ft/sec center ssr, 354 ft/sec center of cyl ssr. Some estimates on port energy are welcome. I am ready to post but need D.V. approval first. Super interesting stuff! Thanks, Charlie

How big is the port in its final form?

[Carnut1]

0130172028_HDR.jpg

Comparison to original flows. For those who care the swirl at .7" lift is a nice 3144 rpm, 291 ft/ sec center of the pinch. 340ft/sec cyl wall side ssr, 367ft/sec center ssr, 354 ft/sec center of cyl ssr. Some estimates on port energy are welcome. I am ready to post but need D.V. approval first. Super interesting stuff! Thanks, Charlie

How big is the port in its final form?

248cc intake 91cc exhaust.

[CGT]

248cc intake 91cc exhaust.

That is a huge port for an unwelded pushrod pinch. Keep us posted.