What gear ratio to use with this PG?

[sixgun86gn]

I was going to use a th350 in my LUV project but I got a good trade on a TCI PG w/trans brake and an 8" 5000 stall converter.I plan on running a built 4.1 with GN1 heads,218 cam,pt70 gtq turbo etc...What rear gear ratio should I use with this trans and 28" tires?The converter was used on a BBC so it might not stall at 5000 with the v6 I think maybe 4000.I think it would haul booty with 600hp.

 

[chris718]

if your truck is heavier than 3000 lbs and you only have 600 horsepower,then no matter what final drive ratio you have i would have to say you are going to have a problem .you have made an unwise deciscion imo.a final drive ratio that will give you adequate starting line ratio will kill you after the first 120 feet and put you in a dead zone in direct drive with a powerglide.i really hope that your truck is 2800lbs loaded or else find a buyer for the glide and get a 3 speed.that convertor is going to be a boat anchor too.im not looking to beat you up here just giving you the facts as my brain calculates them.

 

[sixgun86gn]

Weight with driver should be around 2500.

 

[chris718]

youll be ok then..what is your projected 1/2 shift rpm?this will dictate to a degree the final drive ratio.

 

[sixgun86gn]

I'm thinking around 65-6800 rpm shift.Like I said that converter may not stall as high as 5000 with the 6 but if it does I may go to a tighter converter.Would 5000 stall be too much to shift at that rpm?I will be using a hydaulic cam for now so I cant rev too high.

 

[chris718]

the less gear multiplication introduced by the transmission and final drive to the tires the more time the engine should have to be able to gain rpm in each gear.i would leave at 4200 and have the other 2400 or so rpm at work to move the truck.also youll have plenty usable rpm in 2nd to get you down the rest of the 1320 .a super efficient convertor is necessary to make this happen and pull good mphour.that convertor will probably be too loose ,however there is only 1 way to find out.