Which Lenco ratio

[Craddoa]

need some advice,
Nostalgia funny car, TFX 500cu , Nitro, 34.5" tyres, 4.28 rear end does anyone have an idea what ratio Lenco I should use? Thinking 1.31 ???
I know this is not the best rear end ratio but this is all we've got

 

[MM]

That rear gear is actually pretty common in NFC. Is this a completely NHRA legal engine combination?

 

[Craddoa]

Yes although we are in the UK it is completely legal to NHRA engine regulations