I have a large surplus of 25mm box and very little 19mm with just the tran tunnel and a few minor bits left. Is there any major issue with using 25mm over 19mm for the tunnel. I realise it will add a little weight which is not an issue to me but am more worried about losing 12mm from the internal dimension of he tunnel. Will this cause problems or should it be ok? I would rather save the money and more importantly the time going down to the metal suppliers if there is no issue with using the 25mm box.

I have been using the Vodou drawings which remain silent on the size box (they normally state when it should be the smaller 19mm stuff) so it is just the original book that has thrown doubt into my mind.

In my mind as long as the seats fit 6mm a side wont make much differences
Jacko

It will only be +3mm each side if you use the same centres of the tubes.. or if you measure on the outside will the extra 6mm on the inside of the tunnel cause an issue?

I used 25mm for the whole build (though my chassis was 4" wider than the book) and didn't have any probs. As Coozer points out 3mm either side of centres ain't worth getting excited about.

ATB

Simon

I will check tomorrow but I think I went from outside measurements which means the seating area will remain the same but I will lose 12mm inside the tunnel (2x6mm). Is that likely to cause an issue? From pics of others I have seen the tran tunnel is not that tight that it should cause an issue?

Hi padstar Iv just finished my chassis for a haynes roadster I used 25 mm box on all of it
I followed the book step by step an all my clearances are good
So you should have more than enuf space
Dan

12mm is no odds to the prop, it just depends on what gearbox you're using and where it ends up.