I have a few questions i was wandering if you may can help me out. Will 15" of vacuum @1000 rpm be enough vacuum for the map sensor to function properly? I'm building me another engine for my truck and I'm trying to decide on a good hydraulic cam for my it. So far what I have is a .030" 3970010 350 block, trw forged .220" dome floater pistons, ported 993 open chamber heads which should yeild 10.7:1 comp, eagle 5.7" forged ibeam rods, 1.5/1.6" aluminum roller rockers with a throttle body with all the ultimate tbi mods. I'm just trying to decide on the cam.

 

I think that your question should be phrased somewhat differently - will 15" in-Hg at 1000 RPM (I presume idle) tolerated by a stock TBI ECM tune. Map sensor is just that - it will provide equivalent voltage back to ECM. What ECM does with this input is another story all together.

The answer is probably no or you may see very marginal idle performance with a stock tune (I assume that you have 7747 ECM with ASDU or ASDZ tune). However, not all is lost as your ECM's can be tuned to accommodate your engine particulars - it will involve some tuning effort on your part.

//RF