FrontEngineDragsters.Org Forum

Technical => Dan Dishon's Transmission Den => Topic started by: Ponti on March 27, 2016, 01:25:31 PM

Title: Chevy SM420 manual box
Post by: Ponti on March 27, 2016, 01:25:31 PM

Has anyone ever used one of these in a slingshot?

ratios are
   1st              2nd                3rd                 4th                 Reverse
7.05 : 1      3.57 : 1         1.70 : 1          1.00 : 1             6.78 : 1

 Wondering about using just 3rd and 4th.

 Any thoughts?

Title: Re: Chevy SM420 manual box
Post by: bikeguy307 on March 28, 2016, 05:23:47 AM

Those are some interesting ratio's. 3rd and 4th are close to some of the glides I have built for my higher HP customers 1.69 and 1.00. Would be interesting if you could remove 1st and 2nd to make it a true 2 speed box.

Title: Re: Chevy SM420 manual box
Post by: Ponti on March 29, 2016, 08:36:08 AM

I'm just toying with idea's.  Will have to look to see how gears are set in the box.

Title: Re: Chevy SM420 manual box
Post by: ricardo1967 on March 29, 2016, 02:23:20 PM

I like the idea, but I think you're considering what when comparing gear ratios between manual and automatics transmissions, the torque converter provides additional reduction.