there are a couple good articles on t5 installation in the tech section of this site & also at inliners.org in the tech section.
with 3.43 ratio you might not be able to use overdrive very much & a saginaw might be the way to go. depends on how much highway driving you do
& how many hills you pull.
an ideal final drive ratio on flat highway is about 3.00:1. i have an s10 rear under my '50 coupe with 4.10 gears & .73 od gear in a t5. multiply 4.10 times .73 & you get 2.99 which will be great on the highway. my '50 truck has a 67 gmc rear with 3.54 gears & .86 od in a t5. final drive ratio of 3.04. about the same as the car. these ratios will allow me to keep rpms at about 23-2400 at 70 mph which i'm sure the 261s' will be alot happier with! our old stovebolt 6s' don't last long at sustained high rpm on the highway.
just a matter of matching the right od gears with your rearend gears & taking into account the type of driving you do.
robert.


Robert French MY3800FIRETRUCK