I have been told this exhaust fits is250 and is350 as well with minor modifications. Please look into that maybe with muffler shops that have experience first before buying. No returns, No refunds. Buyer pays shipping cost. Asking $750!! Any questions feel free to call or text 239-289-2942. Email is 
Hey Clay
I don't believe the ISF exhaust will fit an ISX50 for the following reasons:
1. The V6 is a 60 degree angle engine, the ISF is a 90 degree V8. So the spacing is different.
2. The piping on the F is roughly 2.5" from the manifold, the ISX50 is roughly 2.25" in diameter. therefore, if it did lineup, which it wont, it wont bolt up.
For these two reasons, alone, fitment would be difficult.
If you want a real answer to this question, send a PM to JoeZ and ask him. He builds aftermarket exhausts for both series, and if anyone should know it would be him.
Lou
I don't believe the ISF exhaust will fit an ISX50 for the following reasons:
1. The V6 is a 60 degree angle engine, the ISF is a 90 degree V8. So the spacing is different.
2. The piping on the F is roughly 2.5" from the manifold, the ISX50 is roughly 2.25" in diameter. therefore, if it did lineup, which it wont, it wont bolt up.
For these two reasons, alone, fitment would be difficult.
If you want a real answer to this question, send a PM to JoeZ and ask him. He builds aftermarket exhausts for both series, and if anyone should know it would be him.
Lou
