I just bought a 89 IROC!!!!!! 350 TPI with 83000 miles!

I'm currently doing a full tune-up before I gtech it and start mod-ing away.

I have a few questions if someone can help me.

1) The IROC is MAF. I currently have a SD TPI from my 305 TA with a blown engine. Is it worth switching the MAF to SD? If so, do I need to replace the whole wiring harness or just the ECM, chip, and a few sensors?

2) When I do my oil change, should I use synthetic? or is it too late with this many miles? I dont know how this works. Should I try it and see if it leaks?

thanks

 

i switched to synthetic with 105,000 miles on the old engine.