I posted this on FF.AU as well, interested in feedback from you guys as well.

Combo will be AU V8 Ute (auto), Crane 2030 cam, Vortech S-Trim at ~9psi, 3.9:1 diff, 3000rpm converter. Looking for 12's at the track w/drag radials. I'd like to not have to shift higher than 5600-5700rpm.

Which headers would you go for?

Looking at Pacemaker PH4001 tri-y 1 5/8" pri 2 1/4" collector OR PH4006 4-1 1 5/8" pri 2 1/2" collector. Or would there really be bugger all difference?

BTW, the rest of the exhaust is 2 1/2" from cats to single 3" over the diff (mandrel bends).

Would stock cats modified with 2 1/2" flanges be OK? Or should I get some catco or catsound 2 1/2" High Flow cats? Or maybe some 2 1/2" metallic substrate cats?

And who sells Pacey's in Sydney other the VPW? Their prices seem a bit steep...

Cheers,
Dave

With the 300rpm convertor you may as well go with the PH4006's. I would also go with a decent set of high flow cats. I run magnaflow boost series 3" cats, they have a stronger internal design which is suppose to be better in forced induction cars.

Another thing, I assume you have had the convertor custom made for the supercharged engine, and have found a way around the limp home mode issue.

Where did you get the Magnaflow Boost series cats from? Do you mind telling me how much they set you back?

Is 3" too big for cats if the collector (and cat-back) are 2 1/2"? Would they bolt up OK, or would i need to get the necked-down to 2 1/1?

I haven't had a converter built yet, but I will probably get Autoflite Engineering to build one for me. Also, its been claimed that the new SCT Advantage software will allow big converters with the EEC, and that AU support is expected by the end of the year...we will see.

Got them from a local exhaust shop here in SA (discount mufflers). List price was just over $300ea but got them for $180 from memory. From memory, the boost series has stainless internals and extra reinforcement. I just left the inlet/outlet at 3", I don't think the step from the 2.5" hearders to the 3" cats would cause any negative issues.

It will be interesting to see how it goes with the 3000rpm stall and 3.9's, because you will be stalling with boost. Just make sure they make the convertor correctly, I had a 2500rpm one in mine (not designed for the supercharger though) but with the added torque of the boost it pushed the stall to 3500+rpm.

Thanks for the info EDXR8.

Will be interesting with the converter...Most likely I'll run the standard converter for starters and step it up when I want to go quicker.

I'd still like to keep it somewhat daily drivable.

IMO the stock stall is great, obviously it won't give you the quickest times on the track but at least it is streetable. Even with the stock convertor, mine stalls to 2500rpm and has traction issues, but at least if you are carefull it is controlable.

Stop thinking so small. go for the inch and three quarter ceramic coated jobs. that will help get the gas away from the head quick in the blown application and help alleviate heat.

Do they still make them? I remember they used to be under part number PH4003, but haven't seen them listed anywhere in a long time.

Interesting point about heat around the cylinder head.

Imo as big as you can get..

Got quoted $1250 fitted w/ XForce cats @ Best Mufflers, and $1740 fitted w/ unknown metallic substrate cats @ Windsor Exhaust Centre...

I'll do some more ringing around tomorrow, can anyone recommend an exhaust place in or around Sydney?

I'm keen on the metallic substrate cats too, just not sure if they are worth the extra $150-odd bucks each...(?)