how much to install 3.55 ring and pinion in 489 case

[sext7366]

ok I am moments away from ordering from summit but i am wondering how much it will cost me to install a 3.55 ring and pinion in my 489 case sure grip 8 3/4 cause I'd like to leave enough money for it plus a small cushion. I'm sure we all know an engine rebuild always requires a little extra money.

[1970440RT]

     I got estimates from $300 to $500 with varying degrees of what is included.  I currently have a 8 1/4 installed in my car with an open 2.71.  My original plan was to install a sure grip w/ 3.55 in the 8.25 but after an estimate of $800 to $1000.00 for parts and assembly, scrapped that idea.  I found a 8.75 core for $50 at a junkyard and getting ready to buy a 3.55 used center section for $200 ( hopefully doesn't need rebuilt ).  I will farm out the assembly and remaining parts, hence the 300 to 500 number.     

[Chryco Psycho]

typically $300 up to 400 just for the labor , the brg kits is approx $100