New/Modified Header Design?

[Daryl Smith]

SpeedTalk discussion on the 'Bashed Header' Video...
http://speedtalk.com/forum/viewtopic.php?f=1&t=45411

[Daryl Smith]

This chart was linked in a Speedtalk thread on header sizing, thought someone here might find it interesting....
http://www.coneeng.com/pdf/Area_Calculation_Table.pdf

Might want to print a copy, as these things on the internet tend to disappear.....sometimes rather quickly....

[CameronSF]

With that being said...there is a lot of info in here but just wondering if there was any consensus among the experienced members here. I've read the original exhaust manifold was good and not worth replacing and then I've read the exact opposite. I pulled my head after dropping a valve seat and now would be the time to install headers if it made sense. Datsun Parts is saying they do not have any more in stock from their manufacturer and do not think they will get any more. Has anyone had any luck with datsunroadster.com or tri-mil.com headers? On a side note - I saw some comments about exhaust velocity earlier here and Dave at Rebello confirmed the exhaust ports on the U20 head do not create the optimal velocity. He recommended installing smaller exhaust valve seats which made significantly more power than the original spec seats.

[SLOroadster]

I have the Tri-Mil headers, the large ones. They seem to be ok, nothing special, but they work.

Will

[CameronSF]

How was the fitment Will? Any other input? Heat, noise etc? TIA.

[Daryl Smith]

Interesting youtube video on exhaust scavenging:


A lot of info here and a couple videos also:
http://garage.grumpysperformance.com/in ... esign.185/

[Daryl Smith]

Have been unable to repost pics of the 4-2-1 header I'm using....I can forward pics to anyone who would like them...

[Solex68]

Forward them to me and I will post them for you.

[Solex68]

Here is Daryl's pictures...Click on photos to see larger!
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20180701_175556.jpg

[spl310]

Looks nice. Did it improve torque?

[Solex68]

We need an engine with Solexes to mount this and then the Tri Mil header and compare on the dyno.

[Daryl Smith]

Sid,

I used it on my 1800cc stroker (specs in the stroker thread). I couldn't say if it improved torque as I don't remember the before....but, the engine did perform well. Would pull from 1500 rpm in 5th.
Best comment was from JT saying it performed like a well tuned SU U20. Not bad for 1800cc pushrod engine....

It also gives a little more clearance around the starter....

[spl310]

The old Bob Sharp manual spoke to the Tri Y as being a good header design. It looked a lot like that one. I put Tri Y headers on a 289 Ford years ago, and liked them much better than the full length tubes.

[Daryl Smith]

Anyone know what happened to the 4-2-1 stainless header that Garm bought years ago? Would be nice to get a couple pictures of that one up too.
1 3/8" - 1 1/2" - 2" iirc.

[Linda]

This thread has 55 posts and started Feb 2005.
Glad to see you designed the part you are satisfied with!
Linda