I have a set of SLP runners with the cold start injector hole that are made to fit 85-88 engines. I am putting them on a Edelbrock vortec lower and a 1991 upper plenum. Other than the cold start injector block off plate, what else needs to be done to run these runners with the 1991 upper?

Where does the hole in the intake manifold go to? Does the passage itself get blocked or just the opening in the runner flange?



Does the passage in the top of the runner need to be plugged as it doesn't get blocked off by the upper plenum?

 

tap the top vacuum port IIRC 1/4 npt make the head flush or lower on the ninth injector hole use a block off kit from ebay or a 3/4 expansion plug IIRC.

 

Thanks once again!

 

Np, you can measure the vacuum tube and use silicone aroun a expansion plug as well, I'm nit sure but I'm thinking it was 3/8. The injector passage to answer your question goes down under the manifold were the huge npt plugs are and gets feed into each intake runner passage through small holes in the intake runner.