I am port matching my plenum to my SLP runners and was just wondering if it would be beneficial to widen and lengthen the siamese in the SLP runners where they meet the plenum.

I have seen it done before, but this is strictly gonna be a street car and won't see much above 5000 RPM.

Would this beneficial for my application or will they work better as is? My main focus here is low to mid range torque.

 

Out the box they can support 5000-5200 rpms on a TPI intake. You could port them out to flow abit more to boost power in that range but dont siamese them anymore if your not gonna go over 5200 rpms.

Porting for flow is good, but siamesing will shift powerband up higher. You seem to want to keep low end grunt and just want more of it. If you could port the runners the whole way thru, you'll boost power everywhere. Just make sure to do the same port job to the base. thats a bigger restriction. Port the base runners and you'll have nice gains

 

I can not say this any better. My runners hurt me more tell I ported the base.

I can now hit 5k w/o much problem but as you mentioned. Mine is mostly a street car as well.