ok, i want to put twin pipes on my 05 iqr 800. i have found some mod twins off of a 600 iqr.. what kind of problems could i have not using pipes tuned for my 800 motor?
The 600 pipes are likely "tighter" which means they are smaller especially in the outlet area. That will cause heat and burndown issues.
Is this an old style 800 BigBlock? If so, SLP is listing a set of twins for that motor in the IQ chassis. It isn't on their website, but it was in the new catalog I got last week.