I have 2 spare RD400 Transmission, one of them I am planning to put it in a RD350 case as per the Topic written by SUPERTUNE
May I know what are all benefits I will be getting by doing so.
https://www.2strokeworld.net/forum/index.php?topic=802.0
Main difference is close ratio 4th, 5th and 6th gear. 1st through 4th are the same gears for 350 and 400. The 350 has a big jump from 4th to 5th and a too tall tall 6th gear. The 400 has better matched gear ratios in the top 2 without the big jump. Downside is a slightly lower final gearing in 6th. At least that's what I remember Chuck telling me.
I have a 400 trans ready to install in my 350. Chuck was going to do it before he lost his shop space. I'm hoping he gets back online soon.
IR8D8R
I remember when I had a stock 350 it used to struggle in 6th sometimes and I was constantly dropping down a gear to get the revs back up. In 5th it would scream and in 6 it would lug and revs would keep dropping.
It's especially bad if you have skinny chambers. No low end and the power doesn't hit until you get it over 6k. If you shift from 5th to 6th at the redline, and keep it at 85 mph in 6th its fine. Otherwise you are going back and forth between 5th and 6th on the highway constantly and down into 4th going uphill. A smaller front sprocket helps. ...But then 1st gear is basically useless since the front wheel isn't on the ground. The whole 400 trans is supposed to be much better. I just hesitate to split cases unless there's something else that needs done. Fortunately I don't live in an area where freeway travel is necessary.
IR8D8R