only asking for opinions so i don't need to learn the hard way...

this is for my 620 pickup with 5 speed...i want a combination of slicks and gears so i can get the most of my setup down the 1/4 mile...

i got 3.90....4.30....and 4.88...third members...i need to choose one i will use...and what size slicks...in a way i want to go with the 4.30s..so that i can put a small size slicks...so my truck will lean back..and will give more traction,,,,and action.then on the street it won't whine out as much..when i put back my street tires...i need your guys opinion..i know the only way is trial and error but ....i need advise..thanks

You are trying to achieve two opposite goals in the one vehicle so you can either do it right for one purpose and not be good at the other or compromise and never be really good at either.

So the small slicks, tall highway wheels sounds like a pretty good idea.

well what third member should i use???3.90.....4.30.....4.88.....????

Go with the 4.30 as its a good compromise and then if you are dissatisfied you still have an option available in either direction.

Go with the 4.88 for maximum acceleration. You'll still have some economy with your overdrive 5th gear (stock Datsun pickups ran about 45000 rpm on the highway, and could do that all day long).

The only thing is you may have to shift to fourth right before the end of the 1/4 mile, in which case the next gear down might actually improve your race times.

The best place to ask at http://nwde.org -- they have 620 owners with 4.88 gears there. Ask for their experienced opinions in the Forums.