Hello all. I have been reading these boards off and on for months now and finally have a reason to post.

I might be able to aquire a 91 RS with a 305 with right around 30,000 miles for pretty cheap. The car is great. All options available.

My question is this. Keeping the 305 TBI engine, what would I need to do to keep up with the imports? I have been doing research and decided the first mods would be the "breathing" and the gears. I'm leaning towards Edelbrock RPM Air Gap intake, Holley 670 cfm TB, Dual snorkel intake (for stock look), Edelbrock TES Headers (1 5/8" primaries), Catco Cat, and a Flowmaster Cat-Back with maybe 3.42 gears. What would this do for this engine?

Also, what cams are proven in these engines?

A 350 is in the future for sure, but a stipulation of the purchase is he will sell me the car IF I don't pull the engine. So I figure I basically have three years or so to build a decent engine.

Thank-You for any information or suggestions.

 

If you're going to pull the motor, I would probably not do anything to the internals of the motor. Yes you need different heads and a cam to really wake up the motor, but if you're going to drop in a 350, I would primarily put things on it that are going to be interchangable......like

1.) an entire new exhaust system (which you stated)
2.) the drivetrain (transgo shift kit, SLP posi w/ gears, and an aluminum driveshaft)
3.) the suspension (you want to get rid of all the parasitic power loss, and this also fixes some of the design flaws; also you don't want to die after throwing in the HP monster later)
4.) dual snorkle (which you stated)

Of course above all else, do a tune-up (preferably with MSD parts). Yes it only has 30,000 miles, but 11 years is still 11 years of constantly changing temps, 11 years of turning on and off. Also that's 11 years of technology that has passed since the design of the car.

Hope this helps...

 

I would ditch the dual snorkle set up unless you plan on pulling the AC as the stock (or even close to stock) tubing wont nearly fit. You also have to bend the AIR diverter valve out of the way. Open Element will save you hassles. The RPM's dont have EGR (means chip work), and I doubt the Air-Gap will fit under stock hood. The LT1 cam is favored around here as it will boost HP and what not fer like $50... Unless you have to pass smog tests (I dont ) then i wouldnt spend the $$ on the catco cat. Edelbrock's will be fine fer yer 305. I wouldnt worry about the holly TBI unit, just do the "free mods" to yours... Just my opinions - I wish I had the time and space to play with my car!!

 

if you are plannign to keep teh motor in the car for 3 years you will be better served to just do teh little things that can easily be made useful on a 350, unless you are really power hungry
the gears and a posi will be a big help, 3.42's are nice but 3.73's are better and will only change your highway rpm by about 150 at 65mph. a full exhaust with a good set of headers and y-pipe, a 3 inch cat or cat eliminator pipe, and a mandrel bent 3inch cat back. do teh ultimate tbi and opther free/cheap mods and then work on teh suspension. having a little more power will help a little, being able to hook will help a lot. you can certainly get the a full second off your et if you take care of the little things in teh engien and the suspension.
an LT1 cam has been shown to be worth huge gains, mated with a performer tbi intake and an ultimate modded tb you will really be movin. just get a custom ship and you will be running very well.

later
tim

 

I'd be inclined to agree with NJ SPEEDER.
If you're gonna run the 305 for a while, improve the exhaust system, do the ultimate TBI mods, and maybe the LT1 cam.Then work on the suspension.The intake and throttle body aren't gonna make much difference until the cam swap.
Handle the ordinary tune-up stuff (wires, cap, rotor,plugs,etc.)
and go to a 3.73 gear and you'll be amazed.
I eventually swapped a 350 into my RS,with a Crane Compucam (kept it TBI), Edelbrock Performer TBI intake and custom chip.
My little RS surprises a lot of people now.
It'll eat 4.6 L Cobras all day long.
-Rich-

 

Since the exhaust will be the first thing I would do, let me advance to the next.

I know this is the TBI section, but since I started this, may I ask a few off topic questions.

What posi traction disc rearend is best? I'm sure the 91-92 Z28 rearend would work, but they seem they would be hard to find. What about 93-current rearends? Direct fit?

Second, what suspension mods should be first on the "list"?

I'm sorry for the TBI section infraction but these are all things that were mentioned previously.

Once again, Thank-You very much.

 

One more thing, Rich92RS350, what type of numbers are you producing with that set-up. If you don't have Dyno or track numbers what about estimates.

Thanks

 

theres a tech article about swapping axles with a 4th gen... never seen it done..but its there.

 

Thank-You CamaroGuy71

 

if ur newhere near chicago ill swap gears/diff. for u. i like doin that stuff... not as hard as it seems.

 

how much? I want to go to 3.73s or 3.42s, I haven't checked prices yet, but I want done right, and cheap

 

I haven't had it in a chassis dyno (no RWHP numbers yet), but I was actually able to test it and run it in on a dyno before installing it in the car. (A friend of mine works for a local race engine builder and we played with the dyno on a Sunday afternoon)I got over 310 HP at 4500 and almost 400 ft/lbs at 2500 at the flywheel.Sometime this summer I should have an ET, but I'm a couple hours away from a dragstrip, so I haven't run it yet.I'm afraid I'm gonna scatter the T5 tranny, so I'll probably wait until the TKO is in to test it at a strip.

I transplanted a posi/disc rearend from an early 80's Z28, after having it rebuilt with new 3.73 Richmond gears. I actually got the rear from a garage sale for $50, and the guy apologised for having already sold the sway bar off it!

As far as suspension goes, Id replace any sloppy/worn parts first,then A-arm and sway bar bushings,springs and shocks/struts,then maybe rear lower control arms and panhard.

All my bushings are poly, except the A-arms , which are the Global West Del-A-Lum.More info in my Sig, below.
-Rich-

 

^that's the longest sig I've ever seen^

 

^^ and yet no times anywhere ^^

 

if i had to do it all over again.. i would do 1.headers/exhaust/cat
2.rear end
3.aluminum driveshaft,lca and panhard rod, subframe connectors
4. lt1 cam with edelbrock tbi intake
5. either a shift kit or whole trans with higher stall- depending on rear gear. ( i have 323 rear with 2400 rpm stall )
6. cooling help..water pump,trans cooler,radiator
7. head work


this is unless you going to swap to a 350. then i would stop after 3 but if you going to keep the 305 like i did, do all 7 steps and you be near high 13's.

 

lets see...what did it cost me.
SLP take off posi- $92 something
3.73 richmond gears- $180 something
Richmond gear installation kit- $120 something

labor: priceless

but if u wanna do it, email me.
im out in desplaines. 3.73's are like the best mod i did..other than redoin the whole engine.

 

That setup sounds almost like mine, and yes I have no numbers yet, and still have the 2.73 open rear end. The place that I was going to have the dyno done closed shop and now I have to find another place to go. I'm bummed.
I've never run the 1/4 mile either. Still have some ways to go.