carb to efi conversion camshaft considerations

[5.3LS10]

Hi everyone.

I have a 1986 olds cutlass with a 350 SBC with a Howard's 180325-08 camshaft with vortec heads and a performer rpm intake and holley 750cfm carb. Also running a msd 6 box with their pro billet distributor.

So I am wanting to go fuel injected for this next year. I have an lt1 intake that has been worked over to bolt to the vortec heads and lineup with the intake ports. Coincidentally a couple weeks ago my msd box died as well. I am at the point where I have put DIYAutoTune's 36-1 trigger wheel on the car and am planning on using my ms2 to run 5.3L LS coils in wasted spark off the crank signal. I have it running on my jimstim fine but my concern at this point is the 108 LSA of the camshaft. The car idles at around 12.5-13" of vacuum with the current carb setup but is steady. Will I have issues running with speed density? I assumed if I had eratic map readings it would give me issues but what about just a lower reading?

Thanks
Shane

[elutionsdesign]

I wouldn't be concerned, I've seem idle vacuum much lower than that and still be very tuneable with speed density.

[krisr]

My idle vacuum is around 70kpa with 236/242 @ 0.050 on 112LSA - i'm going to 242/248 @ 0.050 on 110LSA soon and dont expect any issues at all. Bigger camshaft, try more timing at idle or if your car is an automatic, you can setup the shifter inhibitor switch with table switching so you have a timing map for P/N and a map for in gear. That's what I did with my current 236/242 cam as in gear it idles with around 35° timing and out of gear it only wants around 20°.