I am thinking about building my 170 into a high rpm/endurance engine.
My first post is an idea on an intake manifold because the beginning of EVERYTHING is a gas, no?
Start with an Offenhauser 4 bbl. manifold, plug the 4 bbl throats, weld in two intake runners on the drivers SIDE of the manifold so they empty at a spot that will effectively make all intake runners equal length, add two Webber side draft carbs OR two 44 mm Mikuni flat slide carbs to the runners.
The runners would be angled so the two carbs were close to each other so the runners would have a lazy s shape, one s and one z then, and the holes to feed the manifold would be maybe as tall as the manifold and 2 to 2 3/4" long.

Why all this?

(1)The reverb from a closing intake valve.
(2)I picked an OFFY for the short runners and at high r's that reverb can be used by another cylinder.
(3)The separated plenum under the 4 bbl throats is isolating the incoming mix and carb butterflies from the harmonics of intake cycles, maybe eliminating dead spots or negative wave fronts.
(4)equal length runners.

Input?

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Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.

Or do like picture below.

Richard

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Part of Tyrde-Browne Racing

My 2¢:

In general: make it as uncomplicated as you can, no need to spend time on endless multicarb syncro and tuning trouble instead of racing.

Re: 2,3,4) An Aussiespeed intake will give equal length runners out of the box, and comes in different configurations regarding runner length.

Olaf.

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Aspenized

BTW: Have you browsed through the article Slant Six Racing Manual (pdf)?

Olaf.

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Aspenized

Have possessed the entire Direct Connection racing manual since 1985.
I could also add a turbo to what I was thinking, got a 6 into 1 hooker also, they are short collector into 2" which could be enlarged.
Also got a Clifford 4bbl to consider using but thought the shorter better for higher r's.
I really believe in using the large plenum for the valve reverb. Chrysler long ram 413 was designed using it (they had two lengths). Think about some modern manifolds, they have a large plenum and then runners.
What config. are the Aussiespeed manifolds.
Is that a picture of a 170 built up?

_________________
Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.

No it's a 225 daily driver and I don't speed a lot of time tunning it. Yes you do have to sync the carbs, but thats a one time thing.

Richard

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Part of Tyrde-Browne Racing

Just so you know...
I have built a lot of 170's 198s & 225s and when it comes to making power and 'seat-of-pants' torque, you do best with a 225.

If you are after great mpg's, have a cubic inch class limit, need a real high RPM engine or like me, just like to try different combos, then the smaller Slants are fun to build & "play with".
DD

Yes the 170, I came across one in a farmers pasture, sittin for 15 years, a 62 lancer 4 dr. add tranny fluid and fuel, instant sewing machine.

Next I'll address the cam, compare these if you will,
Oregon cam #'s
#243 vs #144
and
#504 vs #1255
What I look at is ramp angle, the .050 compared to .020.

#243 vs #144, the .020 to .050 is same difference but unequal timing.

#504 vs #1255, the .020 to .050 is a little different but same timing.

Both pairs have equal amount of lift difference so I can make a choice between ramp and timing then choose the lift per application, to me lift is like changing gearing, ramp would be factored by what induction you have available and timing would dictate engine rpm (not related to gearing but what you want from your engine), am I close?[/u]

_________________
Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.

I take it the more ramp would create overlap for (what I gather) high rpm operation/increased scavaging.

I havn't read on what timing will do for an application.

I also surmise that lift height is used for max desired power output and say fuel consumtion issues.

I see the later cams are bigger all around.

_________________
Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.