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

[Mark Henry]

I'd look to see if I could find a brass tube to fit, maybe off of an old carb.
If you have a vac advance dizzy that's the first place I'd try to pull vac from. I'd also tee it with the one from the other carb.

[98101]

If you have a vac advance dizzy that's the first place I'd try to pull vac from. I'd also tee it with the one from the other carb.

Yes, good idea. I have a 123 Tune+ (Bluetooth), currently not using the vacuum advance. In the 123 group buy thread I've discussed hooking it up, and no one there seems to understand why I think it would be a good idea.

My one reservation is that I think I'd rather have the manifold vacuum signal, as I've read the port vacuum signal won't be strong at idle. As I understand it this was done to make combustion hotter at idle to reduce emissions. But this is probably still better than no vacuum advance at all + two carbs with 3.5mm vacuum leaks.

There's also an inop vacuum gauge in the dash. I haven't investigated what it's connected to, if anything. I'm assuming it would be difficult and painful to run a vacuum line from the engine compartment to the gauge.