is there a 4 inch to 3 inch downpipe available?

[emarsh]

Will be picking up my new truck this next week. I want to install a BD exhaust brake right away, but would prefer to get 4 inch size for fututre mods; don't have the money right away for a complete 4 inch exhaust system, thought someone might have an adapter downpipe piece for now ( so i can use the existing 3 inch factory system) untill I can afford to get Jardine system.

 

[MikeR]

You would either have to install a 4" downpipe with a 4-3 reducer on the end, or install a section of 4" pipe somewhere in your exhaust. Either way your probably spending about 1/3 of the price of what a Jardine system costs on this project.

If money is tight, then why not get the brake and wait and install it when you get the exhaust?