I have a stock 89 L98 Shortblock TF Heads 218/224 496/503 112 lsa cam and a SuperRam. I'm only getting about 12inches of vacume at idle. The cam in other cars in Comp's site says 15inches. I at first thought I had a vacume leak but upon doing the intake 100% correctly again I am pulling the same amount. The car hasnt been driven (just started) so i dont know if letting the computer relearn itself will help a little. I also hear timing can change vacume along with with messing with the idle. The car idles smooth at 750 with 15 counts on the IAC, .54 TPS , and 8* timing. Any suggs? Also this changed as I went fromt he LTR setup to the SR If I rev it to 6K and let off It'll come down and die unless I blip the throttle. It'll only do this fully warmed up. Is it something i may have to change in the chip?

 

Idle mixture can change your vacuum readings by several steps. If you have reburned for the new set up, I'll bet that's it. Probably lean at idle...

 

ahhh ok I am getting a 140 block learn at idle.

 

Well I threw the bone stock chip in and it doesnt stall after I rev it now and the BL's with the stock chip are about 132 and vac is up to 14in now but the idle is like 625 cause of the stock chip. Makes a nice thump thump sound.