Rear end gear ratios

[fourthirty]

I am working on a chassis that will carry a 1930 Model 255A Natural Wood Special Delivery. I have a set of 3:54 gears to replace the stock 3:78's.
The engine is done and it has a Burlington crank and 5.5 head.
Will the hope of an extra 5 mph top end be offset by the 2500 plus lbs. of the wood body?
What has been your experience with the 3:54 ratio?
Thanks, Tom

 

[Del in NE Ohio]

I put a 3:54 ring and pinion set in my '31 CCPU. I gained approx 5 mph in high gear. I run "B" engine with 5.5 head.