TH 400 1st gear?
 

Been "advised" much concerning correct 1st gear needs for my 3500 lb car with 5.14 gears and 30" tire, behind a decent BB chev Stocker and TH 400 trans. Any "rule of thumb" I should be using?

Re: TH 400 1st gear?
 

You didn't say if it's a Stocker, S/S or bracket car but the stock 2.48 is a good starting point. Keep in mind that we're racing at least 1/8 or 1/4 mile and not just to the 60'. A close ratio trans may result in a slower 60' time but due to less RPM drop on gear changes, could result in a quicker E.T. On the other hand a trans with a wide ratio, say a 2.75 for example may provide a quicker 60' but may fall down too much on the gear change. Converter stall also comes into this discussion as well.

Re: TH 400 1st gear?
 

Says BB chev stocker

Re: TH 400 1st gear?
 

Have been told about the "fall Down" several times. Converter is a ATI 8" set up pretty loose. Haven't run it yet but anticipating a flash of around 5800-6000 rpm. I wish cost wasn't an issue, but of course it is......making the mistake on the ratio is concerning. Have been looking at the Coan LW 400 with the 2.48....and comparing with same trans with the 2.75. any way to determine existing trans 1st ratio? It's a Kilgore deal, recently freshened locally, but the trans guy said he couldn't tell and Kilgore "couldn't" locate original build paperwork.

Re: TH 400 1st gear?
 

What class and combo BBC?

Re: TH 400 1st gear?
 

70 Nova.....B/SA....402", GM 401 Alum Head

Re: TH 400 1st gear?
 

Turbo 200 with 2.75 low, swap converter for one for a 200. Put the 400 in a pick up truck where it belongs. The fast big blocks are successfully run in 200s.

Re: TH 400 1st gear?
 

..Or 33.5' Class A 454 motor home, like the last one I built for anything ;-)

Re: TH 400 1st gear?
 

Or sell TH400 to bracket racer, I ran my TH400 for many seasons no issues @ 700hp and 2900lbs.

Re: TH 400 1st gear?
 

so much for defending stock racers as being snobby.....LOL