# Transmission and Flywheel advice



## Hammertime (Aug 11, 2009)

I'm considering building a 4-spd muncie with one of those overdrive gear sets. The set runs an .8X ratio through the cluster and where 3rd gear usually is. Has anyone run this transmission? Is the overdrive (3rd) gear noisy running through the cluster? 

Also, since I'm considering switching to the 26-spline input gear and therefore requiring a new clutch, i'm considering an aluminum flywheel. Butler performance advertises an aluminum flywheel at half the weight -- is there any disadvantage to running an aluminum flywheel? does the car lunge without the extra inertia of the steel flywheel?

While I'm at it - specs... 406 ci 69 gto with a wide ratio 4-spd and 3.55. I wish the rear-end was closer to 3.23, but trying to avoid a gear-swap. Looking at taller tire combos as well. current tire size is 215/70R14. I'd consider up to 16's. how much heavier are 16" steel rally's than 14"? any tire/wheel advice is welcomed as well. thank you


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## geeteeohguy (Feb 2, 2008)

I wouldn't recommend an aluminum flywheel for street...you'll lose low end torque. They're good for revs, and HP, but not really that streetable getting going. They make shifting faster, though, due to less inertia. I had a 3.55 gear in my '65, and put in a 3.36 gearset....the longest legged ratio that will fit in a 4 series carrier. With the 225/70/15 tires I run in the rear, the actual, on-road ratio is 3.23. What a difference. I love it. This is with a 4 speed. The OD kit you mention will also change your shift pattern. Haven't driven one of those boxes, but itf the bearings are good, it would not be noisy on the cluster. If it were me, I'd re-gear and leave the trans alone. I'd also keep the steel flywheel. Good luck.


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## Hammertime (Aug 11, 2009)

thanks for the comprehensive answer.


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