Originally Posted by EdgarTurbo (Post 188363)

Hello guys,

I'm building a 03 mustang mach-1 and i was wondering what are your thoughts on what will be the best choice for my application or any thought at all. I'm undecided on what will be a good choice for me. In the rulesbook said that O.D. gear is not required but at the same time said that the car have to have the same number of foward speeds as original, that's kind of confusing, But anyway if I got the option what will be your choice. Any thoughts will be greatly appreciated. Thanks in advance!

Edgar

Originally Posted by Chad Rhodes (Post 188369)

considering you won't find a clutch assisted 5 spd jerico or g-force. I'd say a 4spd

Originally Posted by Jeff Lee (Post 188437)

All I know is the late Bob Pott (K/S & L/S 5.0 Mustang); now driven by his daughter Kelly Pott-Hall) switched from a 4-speed Jerico to a 5-Speed. He was told by "all the experts" the cost difference of a 5-speed wouldn't make any noticeable difference, so that's what he ran for all those years.
Then he made the switch. With no other changes he picked up two tenths.
I'm under the impression the less the torque and the less the RPM capability of the engine, the more of an advantage a 5-speed has over a 4-speed.
And if there was a difference of $5K between the two offerings and I thought I could get two tenths without any other changes, I think it is money well spent.

I'd also highly recommend the Sportsman dual 7" clutch assembly. The idea here is to keep the weight as central to the crank centerline as possible. Again, I think small engines really need this. PM me if you need more info.

By the way, I think an '03 MACH 1 would be a really fun stocker! What class does it fit?

Originally Posted by Mike Keener (Post 188486)

I agree with Dave Casey's findings and I will be the first to admit I know nothing about the Ford engines power band, or how it effects performance when switching from the 4 speed to the 5 speed, but I do know about the LT1 Chevrolets' abilities in these very same areas.

Probably few remember but Merc and I ran a 94 Camaro LT1 powered car in 1999 and 2000 which Woodro did the engines for and was the D/S NHRA National Record Holder @ 10.52 which was pretty quick in it's day. For what it is worth this car never ran as quick with the 5 speed as it did the 4 speed. On the best days it was a wash and most of the time the 4 speed was a couple hundreths quicker, so unless there has been some startling new developments in this area lately (like a higher/wider rpm power band) I think the data we achieved in this application is fairly factual.

In fact I still have a like new G Force 5 speed available with a 3:16 low and a 3:25 low gear set complete with a Long Shifter and the correct driveshaft for a late model Camaro if anyone out there is interested.

MK

Originally Posted by Jim Caughlin (Post 188622)

The only way that I know to get a high gear of anything other than 1:1 would be to use a 5 speed as a 4 speed. All 4 and 5 speeds that are currently being used in Stock and SS 'lock' the main shaft in high gear and therefore have to be 1:1. Trust me, if there was an easy way to underdrive one of these, I would be doing it. I run a 4 cylinder in SS/FS with 6.50 gears and 28" tall tires and would love to have more RPM but that's all that is reasonably available. In the past, I have run 7.17's in a Dana 60 but they have a limited life. In the good old days of Doug Nash transmissions, there was a bolt on input underdrive unit available but nothing for our current transmissions. Not that I in any way miss my Doug Nash. The other drawback in my combination is the tiny input gear required for the low 1st gear ratios, the distance from the root of the tooth to the outside of the spline makes them capable of exploding, this leaves you with 5th gear only for a very fast trip back to the pits, probably exceded the 15 MPH speed limit...

Jim Caughlin
6019 SS/FS