I did a search and found nothing on this. I am building a new 383 supercharged motor and was wondering if the gears I have in my 12 bolt are to high? I currently have 4.10's. I plan on running around 10 lbs of boost. do I need to drop the gear ratio or will I be fine at 4.11? This car isnt a daily driver but a weekend and strip car.

Thanks
Matt

 

You will likely run out of gear in the 1/4 with 4.11's unless you are building a very high rev motor and run a tall tire. I'd suggest estimating your trap speed, and using the redline of your combo along with tire size to arrive at the optimum gear. You want to be a couple of hundred rpm past peak hp when you go through the traps. Most likely it will be 3.73's or even 3.42's. When I had the M6 I cam pretty close to maxing out 4th at 6,400rpm (with a 6,200rpm power peak) and a 26" tire using 3.42's.

Rich

 

Rich is right. Your probably gonna run out of gear with that setup. With my old 4.10's in my M6 and 26" ET streets, I was going through the trap in 4th at about 6000rpm. That was running a low 12 on the bottle. I'm gonna eventually build a stronger engine that will handle my future setup. An S-trim with the bottle. I went with a 3.73 gear in the 12 bolt in anticipation of that set up. Didn't want to get stuck going into 5th.

Ken R.

 

All motor and any power adder is different when it comes to gears. I would think between 3.42's and 3.73's would do depending on tire size and what rpm you rev to.
-Mark