My question is What kind of power gains can I reasonably expect.
I have a 91 RS wuth the TBI 305. I am planning on the ultimate TBI mods and currently have an open breather. I am thinking of underdrive pulleys, 8mm wires, hypertech chip, and possibly a complete ignition system I also will go with a cat-back ssytem.

The motor has a lot of miles, and will be doing a complete rebuild later on. I would like to try and get as much out of this one as I can though.

Any thoughts on what I'm planning on doing or advise would be greatly appreciated. The open element already seems to have help a ton.

Scot :rockon:

 

The concensus here is to start with headers and exhaust on any V8 thirdgen. That way you are addressing the worst problem a 305 has and also setting yourself up for long-term useage, even with a 350 or 400, without wasting a penny in the long run.

305s, regardless of their intake type, have lousy heads and a lousy cam. TBI heads are so worthless they can't even be ported. Start with some 081, 416 or 601 castings from the junkyard (cost about $25). Follow the instructions linked at the end of my sig and you'll have a set you'll want to keep using on the bigger smallblocks, too

If the 305 shortblock is not in good condition, i.e., you suspect the rings or bearings are going bad, then don't put a nickle into it. Go straight for a 350 and save yourself a bunch of money and grief.

But that good exhaust and set of heads will work really nice with a 350, too. See where I'm steering you?

 

I wouldn't expect a whole heck of a lot out those particular upgrades. In fact, the Hypertech chip (IMO) is worthless. I've looked at a couple on my TunerCat software and all they do is change the WOT settings a little bit, burn a $3 prom chip and then charge you over $100 for it. Everything else is left alone.

The wires are definitely good tune-up items if your car has a lot of miles on it. In fact, I would definitely tune up the whole ignition system- new cap, coil, rotor, etc. If these are pretty old, you'll notice an improvement right there. Also, change your fuel filter and run some cleaner through the system on your next fill-up.

The underdrive pulleys may also give you a little bit. But in the end, they can't slow down the accessories too much or you won't charge up your battery or cool the engine down sufficiently.

 

Be sure you're planning on <b>ultimately</b> getting spanked a lot...

Nice car, bad engine and induction.