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

[craig downs]

I have a 2270 with 45 Dellortos and a Mallory Unilite distributor. I had a similar experience as you have with a off idle stumble. When taking off slow from a stop it would jerk around a little before taking off unless I took off fast. I played with the everything from timing, jetting, float levels, accelerator pump, clean carbs, and coils. It did get a little better but it was still there a little so I thought thats how it is coz I tried everything I thought. One time I was cleaning the carbs and noticed some of the auxiliary venturis were a little loose in the bore so I tighten them up until all the wiggle was gone. I would always try to make sure these were tight but they would loosen up. This time I notice that a couple of the set screws would not go all the in and would stop at a certain point so I retapped them. When I tighten them I wiggled them until they were tight in the bore. When I got it all together and drove most of the hesitation was gone and thought wow this is nice. I also learned that the transition from low to high circuit was lower than I thought and leaned the accelerator pump and that removed the rest of the hesitation. That's been my experience. After thinking about it I thought if the venturis were loose then maybe some air was getting between them and either delaying the high circuit or leaning it.