First off, I have a 1986 F150 with the 5.8L H.O. and an Edelbrock 600CFM carb and the Edelbrock Pro-Flo 1000 Series Air Filter.

I installed a 1" 4-hole carb spacer and I cannot get the idle correct now. I sprayed starting fluid around the base of everything to check for leaks and there are none (I replaced the studs and the two factory gaskets, and one of them is new that came with the spacer). Idle in park is smooth, but about 1000RPM with a vacuum reading of 14. In park, idle becomes very rough, about 400-500RPM (needle shakes a lot) and vacuum of about 8-9. Before I installed the spacer, idle and vacuum were at spec. I tried adjusting things but I cannot get it correct.

I'm not sure what to adjust or how much? Will my vacuum be a bit lower with the spacer on? Help please!

 

Well, first check the ignition timing. You may need to up the jet size due to the extra airflow now entering the engine. Spacers speed up airflow coming into the intake manifold. It sounds like it is leaning out a bit. Have you tried adjusting the mixture screws? The Edelbrock is essentially the old Carter design. I can't remember if it has metering rods. If you can't get it, try and give Edelbrock tech line a call and see what they say.

 

I recently checked the timing, so that is good. As for jets and rods, I unfortunately know nothing about them I have tried adjusting the mixture screws, idle screw, and high idle. Perhaps it would be best to talk to a tech and see what they say. If it does come down to the jets and rods, I know someone that can help me (hopefully) with them. Thanks.

 

Just found out I can't get the kickdown bar on either, this sucks...