[Blkdak1999]

I ran my 99 sport v6 5spd ext cab at our local 1/8 mile track last night. My times wern't what i expected. An 11.8 was my best. Any shifting tips or launching tips because i was lost at what rpms to start at and whats a good rpm to shift at. The only mods I have are short ram intake, RT throttle body. Would i see any improvments from a posi rear end? Better tires, headers and exhaust? I have 3:21 gears.

Thanks
Jim

 

[HemiDak]

Would i see any improvments from a posi rear end? Better tires, headers and exhaust? I have 3:21 gears.

You don't have 3.21 gears, it's either 3.55 or 3.92. Yes, a LSD differential (aka Posi) will make a big difference if it's an open right now. Open rearends suck and every single one should have been made LSD.

 

[realdeal7369]

launch at about 1600 rpm or so. shift at aboyut 5000-5200rpm. you should be getting near the top of third by the time you hit the lights. get a set of 1991 exhaust manifolds. headers are a bit overkill for a stock motor. get a bigger thottle body too. as far as tires go, what size are they now? get a tape measure and see how tall they are, the taller they are, the lower final drive ratio your working with. 26-27" tall tires would be the cut-off. andthing taller than that, and its time to think of changing the rear gears to a 3.92-410's which is what i would do anyways.

 

[Blkdak1999]

really 5200rpms. And the 91 manifolds will bolt right on?

 

[mtlcafan79]

You don't have 3.21 gears, it's either 3.55 or 3.92. Yes, a LSD differential (aka Posi) will make a big difference if it's an open right now. Open rearends suck and every single one should have been made LSD.

3.21s did come in the 5spd trucks.

 

[realdeal7369]

really 5200rpms. And the 91 manifolds will bolt right on?

i got them on mine...

the inside of them is more open than the later model ones. i just wish i did some porting and polishing on the v6 heads while i had them off a while ago...along with a different cam too. you might have to make a small metel braket to cover the egr hole on them though, not sure if you have one of those on yours or not.

 

[MoPaR DaK]

You do not want 91 manifolds... those are premag. What you do want is a set of 92-93 manifolds or just get a set of headers.

 

[HemiDak]

3.21s did come in the 5spd trucks.

Seriously? Hmm, that's quite stupid. He should definitely install a 3.92 or a 4.10 in there then.