you shouldn't have a problem running 5w-30. more details on your combo though would help. what supercharger is it? if it's not self contained(procharger) you can't go too light on the oil.
Thanks for the response. I have just about every mod you can think of. It's a Vortech V-2 SQ S-trim(has since been superseded). Andersen FMS B-31 blower cam, 30# injectors, FMS 65mm TB, TrickFlow TW ported stage 1 heads, upper/lower cobra intake, Pro 77mm MAF, MSD Boost timing master, MSD 6AL, MSD Blaster coil, Kirban FPR, FMS 190lph in-tank fuel pump, T-Rex external pump, Renegade upper boost pulley, PI Stallion stall convertor, TransGo shift kit, slimline tranny cooler, 3.73 gears, BBK Jet-Hot equal length shorties, Bassani X-pipe sans cats, AR3932 extra cold spark plugs, Chris Johnson Motorsports ECC IV custom chip, Steeda subs, FFR upper/lower rear control arms, Suspension Techniques lowering springs, KYB shocks and struts. And these are just the internal mods. I've had this car since 1996 and have been modding it since. 38k original miles too! The exterior has completely changed too with body kits and so forth. I used to race it when I was younger. It's a sub 12 second car at about 120mph trap. it's a whale of a car at around 4000lbs curb weight. Dyno-ed at over 500HP to the road. But the last seven or so years, I've just taken it to car shows and I'm waiting for the right individual to buy it from me. Recently I had to use it to go to work since my main car needed repairs. I got great results with 0W-20 synthetic in my Mazda and wondered if I could use a lower weight synthetic on the Mustang. Back in the old days when I'd buy 110 octane for $5 a gal at the track, it didn't bother me if my mods gave me 12-15 mpg. Now I'm into hyper-miling on my Mazda. Funny how things change. Anyway, I was also wondering if using Lucas Oil in the tank would help clean the valves and other internals safely. With an engine like this, I'd hate to use something harsh like Seafoam. I'm hoping the Lucas UCL oil will play nice with my fuel pumps and computer chip.