The cat on my 1990 F250 5.8 EFI is clogged and I dont want to spend the money on a new oem replacement. I have found plenty of replacements that are cheaper although they don't have the 4-bolt flange on the inlet side that is on my existing system, also the inlet on stock is oval and after-market is round. Do any of you have a simple solution, or maybe know of a conversion kit that goes from the 4-bolt flange to 3" so that I can use a cheaper (probably better) after-market cat?

 

Just buy a 4 bolt direct fit. The cheaper cats you are looking at and planning on using are not rated to handle a vehicle that large. They will overheat and fail, they don't flow enough, its a different flavor of the can of worms you are in now. If you want to do this right there is only one cat out there that is built properly. The problem with most brands and the OEM is the cheap packing they use around the catalyst, deteriorates over time, allowing the substrate to loosen and break, from there is just plugs up. The part I will recommend uses a better packing material that holds the substrate better.

How long are you planning on keeping the truck, does it have a smog pump, and does it have an EGR?

 

1st thanks for replying, but yes it does have a smog pump and an EGR, and I hope to keep my truck for the next 5 years or so, It has been very reliable and the motor is in great shape. But speaking of the smog pump I know which ever brand I buy It needs to have the fresh air supply tube coming out the top, so which one did you have in mind?

 

This one has both fittings, and a catalyst while smaller than OEM is larger than most other aftermarket, and has the weight and displacement ratings to handle your truck.

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Thank you, it's exactly what I need, I just wonder if I can find it a little cheaper on a diffrent site.