say i get the 90mm, i have and LS6 intake manifold (i have a 99 it didnt come with the LS6-as your prolly know), is that what you were talking about or would i need to get a different one?....would i see a difference in perfromance out of my car?

 

The 4.10 hasn't hurt my top end that i've noticed. 5th gear will still pull all that's on the speed-o! But who runs that fast on a regular basis? I get more enjoyment from out the hole to 115 anyway. As for your t-body question, I'm putting a BBK 80mm on the LS6 intake I just bought, so I'll let you know soon afterit's all done and dynoed.

 

If you were to get the 90mm TB you would also have to buy a FAST manifold, It wont bolt up to an LS1 or an LS6 manifold

 

thanks superdave and 02ss....i appriciate it, i dont think ill go with the 90mm then if i have to get a whole new intake manifold, but def let me know how the 80mm goes superdave, i may go down that route.....and your right as far as the top speed, i dont and wont run it that fast that often but its nice to brag that it will bury the speedo,.....i think i may go with the 4:10s as well if it dont hurt top end that bad...thanx

 

I would not bother with a 90 mm throttle or fast 90 mm intake manifold unless you have re-done heads and a cam. A stock engine really can't use the added capacity.

 

I was under the impression that the rear end isn't really strong enough to take 4.10s in the rear safely. Doesn't it often break from that?

 

All the time. Count on replaceing it soon. They are the weak link. Nothing you can do about it except replace it.

 

Sounds like someone needs 4.10's in a Ford 9 inch rear end