My blazer runs a mild 454 400th tranny 60 front 14 rear wit 410gears.I need lower gears it is not street driven muds drages and trail rides like in gillbert minn.Im not really in to rock crawling i 4 got im runniing 38s.  

I would say 4.88's here. If you had a 4L80 I would say 5.38's. The later combo would have about a bit lower cruise RPM than you have now too. Many years ago i used to be a big THM 400 fan but those days are long gone for me now with 4 speed autos available as they can really shine with proper axle gearing.  

Thanks 4 the imfo im not morried about crusing rpm becouse dont drive on the road not street leagel.