Okay, I'm thinking about that 402 from SLP. With a decent cam (230/236 .575 114LSA) and good heads (warmed up 6.0 ones) I figure it should make an honest 425-450rwhp and some absurd rwtq around 550 or so.
With a normal weight of around 5300lbs (appx) my truck should run
[email protected] MPH. OR around 8.6 in the 1/8th mile around 85mph.
Anyway, I did some math with the gearing of the 4L60E and shit as well as with what gears I'm looking at either the 4.10:1 or 4.56:1. Well with a 4.56:1 I'd be into 3rd gear in the 1/8th already and cross the traps around 4000rpm in the 1/8th. If I still went on to run a 1/4 I'd cross around 4900rpm...If I ran a 4.10:1 I'd be around 5800rpm in the 1/8th which is better than 4000rpm. I don't want to rev to 6600rpm in a truck even if I have the cam to support it...I have a 402, it's got TQ out the ass I don't need topend HP.
From my memory you want to be at the top of the powerband when going through the traps and a 4.10:1 would be about 600rpm less in the 1/4 vs a 4.56:1 but I could honestly give a shit about running to 110mph in a big truck.
So it looks like a set of 4.10:1 gears would be better for the drags AND economy... :think: