Originally Posted by TopspeedLowet
I always determine my or your gear ratio based on the predicted or the actual MPH you will be running at which ever finish line you are racing to.
If you had an automatic trans and thought you could make the power to run 161 to 164 MPH at the finish line and you had 102" roll tire and wanted to rev 7650 RPM in the lights 4.33 would be a good choice no mater what your power came from blown or sucked. If you think you have more than that then maybe 4.10 would be better. Only the power that your engine actually makes, its weight, tire roll out and RPM you are targeting at the stripe is known you will be guessing what one is perfect for you in the end. I hope this gives you some insite on your question.
this is above my head..i don't have car or engine built yet[done i mean]i've got all engine parts but not togeather yet.so i have no ideal what speed or rpm i'll be doing across the finish line.the reason trying to find out if i need to change rear end gears or not is because when i called my converter man to build a converter he said it would make a big differance on converter build between the gears i have now[4;88] and the 4;10 and 4;33's i'm being told i should go with.i'm on disabilty so can't afford to have on built for my 4;88 and then find out later i should go with 4;10's and then would have to have another converter built.gears cheaper to change then converters.