BC GTA

I am about to acquire a custom PROM for my car to account for all the modifications I have done, which you can see in my garage. The only thing that is delaying this is I may move to a location that has vehicle emissions testing and I have no catalytic converters, air pump, etc.

So if I got a custom PROM now and then had to install high flow catalytic converters would that affect the custom PROM much?

Grim Reaper

If it is for your MAF 5.0, there is little changes necessary to the eprom other than properly tuning it in the first place. I helped a buddy tune his 383 and there were not that many more changes I had to make to his eprom from his original setup (ZZ3 ported aluminum heads with a hydraulic roller to AFR 195s with Competition Porting and a solid roller setup). The primary changes were for the larger injector size and to work on the idle (due to the lumpy cam). But, because we had properly tuned the MAF Scalar tables, these required no further changes.

The other big change was for WOT as we were maxing the MAF at less than 4,000 rpm.

So, if you get a GOOD tune in the first place (and that means the MAF Scalar tables), you should NOT require any further mods once you install the cats.

BUT, before you throw good money out, get a CLEAR explanation of what the person plans to do for you. Frankly, other than a good initial tune to the MAF Scalar Tables, MAF systems require little tuning other than for injector sizing, idle and WOT (if you are maxing the MAF) and a Naturally Aspirated 305s won't max the MAF.

BC GTA

Thank you very much. Yes everything is as described in the garage.

Fastchips recommended Wester's Garage in Canada who I have been in contact with.

I will ensure the the MAF scalar tables are addressed. I also want to adjust the primary fan on/off settings.