All Small Six Flow testing the "log" heads

This relates to all small sixes
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An application specific EFI intake is already being discussed. It will feature a front mount TB, and will be similar in design to other performance based intakes on the market for other inline engines. 3D modelling is currently underway. Since the removal of the log is such a unique modification, there is no established flange bolt pattern or consistent thoughts yet that could make this a production part, so anyone feeling froggy to jump in and help provide that data can speed this along nicely. HINT, HINT.....
 
CNC-Dude":1a1bes69 said:
An application specific EFI intake is already being discussed. It will feature a front mount TB, and will be similar in design to other performance based intakes on the market for other inline engines. 3D modelling is currently underway. Since the removal of the log is such a unique modification, there is no established flange bolt pattern or consistent thoughts yet that could make this a production part, so anyone feeling froggy to jump in and help provide that data can speed this along nicely. HINT, HINT.....

I can't wait to see it.
 
The flange on the head i am waiting on bolts to what looks like a old Lynx manifold, Aussie made and long discontinued, thats why if viable i can reproduce the flange and manifold, the new flange could be a laser cut one and new manifolds poured to keep costs down, i need to figure whether the flange will bolt up a triple webber manifold or be changed to, then hopefully a kit can be offered once i have it all going and do some testing and crunch the numbers i will have a better idea but its in its infancy.
 
"...will bolt up a triple webber manifold..."
the one Offenhauser offers for this engine is not usable?
 
"...should all arrive late this week..."
Thanks mate, but is it the 1 we talked bout back channel, or an "Offie"?

Time to move this thread off the current one?
 
U get the whole motor or just the head?
Hey, reply to my email:

chrlsful@aol.com.

wanna keep this thread Mike's set up as clean as possible...
Thanks,
 
AzCoupe":3knigjoh said:
Over the past few years we've flow tested several Australian 250-2V cylinder heads, as well as our own Aluminum cylinder heads. However we've always wondered how the cast iron "log heads" stacked up, not only to the Australian and Aluminum heads, but to each other, both in stock and modified configurations. Therefore we decided to do a little work on the flow bench.

Since we already had flow numbers from an Australian 250-2V cylinder head and our aluminum head, both in stock and modified configurations, all we had to do was flow test both log heads in roughly the same configurations for a good heads-up comparison. Unfortunately the only small log cylinder head we had in our possession had already been modified and converted to a 2V intake, so we had to guesstimate the stock numbers.

All four of the modified heads included over-sized valves, and were ported in a street/strip configuration. Both the OZ and Aluminum head were tested with the 2V manifolds installed, while the modified log heads were tested with the 2V conversion adaptors installed. I should also note that we tested the #2 ports on all four cylinder heads. All heads were tested at 28" H2O.

The one thing I found interesting, is that with our experience modifying and porting log heads, we were able to get a modified large log to flow nearly as well as a stock OZ250-2V, which I always assumed was impossible.

Summary: We pretty much concluded that it's not worth putting money into a small log head. Even with larger valves and port work, the small log won't flow as well as a stock large log head. So if your going to use a log style head, and you want to increase performance, buy a used large log head and put your money into it. You'll be better off in the long run, and a lot happier with the end results.

For those who'd like more information, I'm working on a tech article that will cover everything in detail, it's just not done yet. However, I'd thought I'd share the peak flow numbers in the mean time. The next step is to spend some time on an engine dyno, which may happen next month if I can afford it.

Here's the peak numbers in a bar graph.
flowbars2m.jpg

What about doing something like I did on my boosted 200 build. Chopping off the intake and building my own. What improvement would me or other people see with no other improvements to the head, such as valves. My head is completely stock besides 302 springs and a custom intake.
lVJOjX9.jpg
 
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