Keep Dellorto DRLA 45s and Bosch 009? Options

[98101]

I suddenly find myself owning 1970 4-cylinder 2.4 with Web hot street Cam idles nicely and pulls hard at WOT. Part throttle response is not great, often with carbs coughing and even backfiring on trailing throttle. My use is mostly street, so I'd like to get this part throttle stuff sorted.

Here's pictures of the stuff that's in there now. I guess that's the infamous Bosch 009 with no vacuum advance and a PerTronix 1847A. The carbs are Dellorto DRLA 45s with short velocity stacks and these tall foam things that don't seal against the air cleaner housings. I'm willing to learn about the carbs but I don't have much confidence in the 009 for running nicely on the street. Please correct me if I'm wrong about any of this stuff.

Also from other threads I gather that switching to EFI such as MicroSquirt would cost $5K or so ... though I'm not ruling this out completely. Correct me if I'm wrong about that.






Is this kind of linkage OK?


Here's the idle you may have seen in another post:

https://www.youtube.com/watch?v=-AC53RRrXOU


Any help you can provide is appreciated!

--Michael in Seattle

[98101]

As y'all advised, I bought an air-flow meter. I was able to measure what was happening at idle. At the time the engine was warm and idling fast, around 1200 RPM. It often idles lower than that.

With only one meter, I didn't see a way to compare the behavior at speeds other than idle. Is there some trick to this that I don't know? If not I guess I'll buy another meter(s) to watch more than one throat at a time while revving the engine. Sometimes when I'm driving, I'm wondering whether it's running right at slight throttle, just off of idle.

At idle I noticed slightly less flow from cylinder #3. It reads 5 while the others read almost 6. Is this a significant difference?

Cylinder #4 below:


Cylinder #3 below:


Idling fast at the moment:


Cylinder #2 below:


Cylinder #1 below:


I also got more legitimate looking air filters from CB Performance to replace the foam things the previous owner had for some reason. But I still have the long studs, so removing the air filters is more of a hassle than it should be. I don't know if it's easy to find shorter studs. I'm tempted to buy taller filters just to reduce the hassle.