Good Looking Build There Mariojr, As to the interior have you tried Green Strawberry they have a Batmobile update kit, Check the link below.....Regards
https://greenstrawberry.cz/batman/batmobile-2016-20.html
Niko,I don't know what search you have tried?but if you put in tunnel ram carb linkages on google or bing..and click on images you should hopefully find what you are looking for...Hope this helps.