Hi there,

I just need to confirm that a early TB (87 IROC) will not work with a newer style plenum (90-92 w/Map sensor port).

I bought a matched ported edelbrock base manifold, ported SLP runners and plenum off Ebay a few months ago. After some research here it looks like I have a SD plenum. I've reused the TB that was on the factory intake on my 87. I assume this is my problem.

Can I put the old plenum on and run the newer style runners? I'm running $6E code and don't use the CSI.

Thanks

Kevin

 

I don't think the TB is any different but you might have a vacuum leak because the speed density plenum has an extra port near the back where the FPR plugs in for the MAP sensor. Unless you cap that then you have a severe vacuum leak.