Has anyone ever used this manifold. I know this is an early dual plane manifold that was designed for low end torque and fuel economy. I have someone who wants to use this intake and a 600 cfm holley single pumper. The vehicle is a 1986 4x4 with 4 speed bull low transmission.. The engine is a stock 1975 Camaro LM1 350 8.5 compression with 882 cylinder heads. I think just for the difference in weight between the original cast iron intake and the aluminium sp2p it would be worth it. The cost is a set of intake gaskets and the time involved to do the work. The intake is a freebie. Or should I tell him to just buy a new Edelbrock Performer.
General consensus is this is a decent manifold for low end torque and fuel economy as stated as long as it is used with a low cfm carb and the 600 would fit that bill. It has no benefit over 4,000 rpm. For free and all the weight reduction over stock why not use it. would seem to me that a 4x4 is not going to be running at high rpm anyway and the 75 LM1 would benefit from more low end torque in that application.
I used one on one of my 455s with a 1" 4 hole spacer and it was good for 5500 RPM.With the small runners, it gave me good air velocity too. I didn't notice any improvement at the track when I switched to a Performer - also using the spacer. Can't swear as to how it would work on a small block as I have no experience with that.