i've heard of some people who use an easy method to increase the performance of 12a.something like they shorten the secondaries spring in order to have the secondary jets open earlier.is there anyone who could describe the procedure and where that spring is located?

 

mechanical secondaries are the way to go! After doing it, it takes a short while to learn how to drive your car again. Mmmmm, took me maybe.... oh.... 1 minute. Anyway, this dirt simple modification was probably one of the single best engine mods I've done so far. Now my right foot is in charge and tells my Nikki carb exactly when to open all four barrels. Check out this thread entitled Carb Crap...Nikki Mods by our good friend Sterling. Good luck and have fun!!

 

i already got mechanical secondaries.i bought my car a year ago.i used to drive it for about 9 months with the secondaries never opened.the previous owner has not noticed that something went wrong with the car so did i cause i never drove a 1st gen before in order to could make a comparison.when i noticed it and had it fixed(my mechanic told me that it should be be better to make it work mech. instead of vacuum activated) i realised that for a long time i used to live in the dark.
now i like the fact that i can activate the secondaries when i want to.the only problem is a little lag just before the secondaries come alive.
anyway do you think i should try to shorten that spring?

 

If your secondaries are mechanical, the spring is not funtional. The spring controls the opening of the vaccum secondaries. So no need to bother.

 

the lag can be minimized by modifying the accelerator pump. Check out that writeup by Sterling...... it's all explained in there.