[KC406RS]

I just bought this motor from a guy and wanted to know what will be a good setup gear and stall wise.
.030 400 block
Balanced, decked, honed and cam degreed
Scat nodular crank
Kieth Black Pistons
Comp Cams
Full roller rockers
Moroso 7qt. pan
Aluminum Edelbrock Performer RPM heads
Victor Jr.
Holley 750 Double Pumper prepped by “Layton Carbs”
Mallory Comp 9000 Distributor
K&N Blow through air cleaner
March Billet serpentine conversion pulley system
Moroso water neck
Factory Chevy valve covers with modified baffle

Right know I have a mild 406 with around 340hp at the crank
and a new turbo 350 good to around 450-500hp with a stock stall and a 12 bolt posi with 2.73 gears. I was told I could go to 3.55's and use the same carrier. Would that be low enough? What about stall 2,200-2,600? I only drive this maybe 750-1000 miles a year, mostly in town.Also would you change anything a local builder said to switch out the victor jr. for the air gap performer I have on my other motor.

 

[67 Plum]

Need to know the cam specs.

 

[68rs406]

Personally, I would go with a stall around 3000-3200 (advertised), it's not as much as it sounds and it will give you some snap around town. As for gears, I'd go 3.73 if you can, or maybe even 4.10 . What size rear tires? that will change gear choices a bit. But my personal choice is more gear (to a point) since it's a low mile around town cruiser.
Try the Vic Jr and the air gap since you have both, around town the air gap will probably feel better, but since 406's makes lots-o-torque the vic might be a good choice as well.
To make a good determination we would need to know cam specs and compression, but based on your horsepower it's probably around 10:1 and a reasonably mild cam, like in the 260-270 advertised duration, just a guess. If so it probably is a torquey son of a gun, and a low 3000 stall, 3.55 gears and an air gap would be plenty of abuse for your tires....

 

[KC406RS]

Cam is a comp 292h (Thats all I know so far)
Tires are 255-60-15
Compression is 10.75
Dynode at 370 at the wheels (4speed,3.90 gears)

 

[HarleyD67]

You'll probably never really be able to ring it out so you won't be able to realize the top end power of the Vic. Jr. So stick with the Air gap. It's good to about 5800-6000. As for gears and converter I would say again for romping around town go with the 3.73's and a 2800 stall you'll be very happy, although your tires won't be.

 

[68rs406]

Ohhh, rear wheel horsepower, that looks a bit more like what I'd expect then.
With that cam I'd go 3.73's minimum, at least a 3000-3200 stall, and either intake. I'd leave the Vic Jr on if you planned on racing it at all, but if purely a street cruiser throw on the airgap.
Should be a tire shredder :thumbsup: