Adjustable cam timing

I have an 89 B2200 with a fresh engine rebuild. Mpg is about 19 - nothing fabulous.
Some time back I read an interesting article about a guy who did a mod to his B2600 for adjustable cam timing. He removed the top gear locater pin, and tapped the hole for a hardened bolt. He slotted the gear to allow + or - 6 degrees cam adjustment. He claims factory cam timing is retarded in smog years to lower cylinder pressures for emissions, and says he found he got better torque with his valve timing advanced + 2.
Has anyone done a similar mod to a B2200? I hesitate to try tapping my cam - but an offset pin might work. I'd love to be able to adjust cam timing for possible better mpg.
JT

You won't have to tap or slot anything. The cam gear has four positions that it can be installed... numbered 1,2,3,4. You will have to do some research on which is which, but "1" is where the factory installed it.

The 2000 has three positions... A,B,CX. "A" is factory. I played with it before. One gave me a bit more low end torque and lost top end. The other gave me a bit more top end horsepower, but lost bottom end.

What do you want to gain, and what will you give up?

Thanks Sin City, for your reply. I am aware of the different positions for installing the B2200 cam gear, but try as I might I have not been able to find info on how many degrees advance or retard these positions give (including the Mazda dealer). It'd be handy to know. I haven't yet experimented on my truck with the non stock gear locations, but I will.

You mentioned what do I want, and what I'm willing to give up? ... Well I want great low end, great top end, and great mpg, ha ha! I know I can't have it all, particularly with a stock cam. But if I do a .030 head mill and install a conservative performance cam of about 450 lift in my five speed truck, I hope I can do a bit more power AND mpg.
Any performance cam will have more valve overlap, causing slight loss of low torque, but I'm thinking that advancing the cam a bit may help compensate for this.
JT

You won't gain anything with a .030 mill. Don't do it unless the head is out of spec. It will retard the timing a little more.
You'd be better off by porting and polishing the intake and head. A cam would do you better too, along with a weber carb... if you don't already have one. Overlap isn't a bad thing. It helps with scavenging.

Yes, you can have it all. Kia FE3 DOHC! Well documented across the inter-web!

I think if there was a way to get any significant or meaningful fuel economy, without sacrificing any significant top or bottom end performance, Mazda would have done it.

Is that 19mpg city or highway? If HWY, then maybe there some more tuning / cleaning of the intake and emissions system that might get you up into the 20's.

Seriously, if you really want it all, I would do the Kia swap. You could probably find a wrecked or rear-ended Kia for $500 to $1000. Then find a buyer for your freshly rebuilt 2.2 engine. Freshly rebuilt and available for a test drive in your truck before you pull it, you could probably get $500-$750. Pull the parts you need, part out the rest, scrap what's left, and you could put money in for pocket with some sweat equity and have it all!