Plenty coming. I got the new build thread being started this week. Got so freaking frustrated creating a boost code with the $8D that I'm running Open Loop with it only. I gave away a lot in the old thread, but I pulled it all because I want it document correctly. Did you see what I did to the 416 heads yet after I went back into them...?

 

I was under the impression that was a destroked 4" bore block not a true 305.

 

listen backwoods retard, I just admitted that I made a mistake of not reading the rest of your post. Get a clue.

 

buuuut LS1's LS2's and so on and so on are not cheap. new or used. unless you find a used one with high miles and its not even in the car so u cant hear it run. 350's and old skool motors like yours are better and i prefer Carbs over EFI, TBI, TPI or wutever other acronym is out there.

Hey streetlethal, i also wanna see pics/vids of ur 305 man. i got a 327killer myself and its a 305 carb'd with extensive work done(not bored out yet but everything else is done) i can also beat the corvette 350 crossfire inject. as well. i can keep up with a 383 but those will beat me at the quarter mile by 20sec

 

NIIIIIIIIIICE

 

his cars badass bro

 

Preston's IROC was a real 305 when it hit the magazines, and at more than full weight, ran in the tens. He switched to a 4" bore down the road when he installed the turbo, but ran an actual 90's 305 with the Vortech supercharger. Here is the article..

"Kinetic Engineering"

"Tucked in among the 200 or so cars that make the pilgrimage to Mac's Ice Cream every Sunday night in Tewksbury Massachusetts, there's litte about Preston Smith's 1985 IROC to distinguish it in a sea of low-key cruisers. Sure, its wearing high-tech rims and skins, but for a generation of enthusiasts no longer able to save its nickels and dimes for 409's, replacing the forgettable factory wheels and tires is usually the first swap made in the pursuit of performance... even though most will never realize the potential of the speed-rated rubber. To Smith's credit, the Camaro's external alterations do extend beyond the rolling stock, but under the color-robbing glare of florescent street lights, the painstakingly applied Sikkens Brilliant Red Metallic is muted down to a dull burgandy not unlike a factory tone.

For all intents, the car assumes the identity of a well-maintained stocker. Even when Preston idles away, there's little to hint of more than emasculated factory power; in 1985, Detroit was on the cusp of a performance renaissance, but power was still all bells and whistles and mirrors, trick decals and hot exhaust notes. Its tough to sell a performance image when, as Smith's IROC illustrates, the top power source is an anemic 305cid small block.

Its tougher still to build a respectable street machine from such limited resources without abandoning the car's factory roots. As the crowd at Mac's intimates by its warm reception when the IROC eases onto the lot, though, Preston managed to do just that. In fact, during the past four years, he's pieced together and improved upon what may very well be the fastest 305-powered street IROC in the country, as evidenced by a growing number of 10-second time slips. On D.O.T. street tires. Through the mufflers.

As Preston pointed out, the IROC's displacement wasn't an issue, but like most horsepower-hungry consumers, he was stymied by Chevrolet's seeming inability to pull horsepower out of diminutive engine blocks. "My original intent was to build an American car with a small, limited-displacement block that could be the cornerstone to a real street driven performance car. You see imported exotics doing it all the time, it bothered me that we couldn't do the same thing here".

To see what the stocker was really capeable of, Smith first revamped the original suspension. The front underpinnings were adjusted for negative camber alignment with a 1/8-inch toe-in, then Preston started replacing parts out back. The stock torque arm was swapped for a fully boxed unit and lower rear links, along with a tubular panhard rod. and progressive-wound springs. All bushings front and back were replaced with polyurethane parts, and stock shocks were trashed in favor of adjustable Koni oscillators. Global West tubular subframe connectors tie the car together. The rear brakes were also swapped for 12-3/16-inch Wilwood discs.

Now that the car was capeable of pushing the envelope on its less-than-steller potential, Preston began to up the ante under the hood. Electing to stay with the high-tech electronic fuel injection, he weighed his options and decided that the best way to meet his goals without sacrificing the car's street-driven capability or gas mileage was with a supercharger. "That way, I wouldn't have to put in a large overlap cam or higher compression". Rather than bust down the original, Preston bolted together a 1990-vintage 305 with splayed four-bolt mains while he continued to drive the IROC. The improved block was fitted with a forged crank, J.E. .030-inch-over hypereutectic pistons (with the tops ceramic-coated by Swain). Mechart stainless steel boxed rods and a Lingenfelter 272 hydraulic roller cam.

Cognizant of the need for the 305 to breathe, Smith topped the block with Air Flow Research Stage One street aluminum heads equipped with stainless steel roller rocker arms and big ceramic-coated valves. They're tied together by Arizona Speed Marine oversize runners connected to an Extrude-honed manifold base; the upper plenum has been ported and matched to the runners. An ASM 52mm throttle body with airfoil (flowing 750 cfm) and Bosch injectors (30 lb/hr) round out the induction.

Oh, yes, there's the matter of that Vortech supercharger - and the 16 pounds of boost Preston has dialed into it. Recognizing the potential side effects of such a highly squeezed intake charge, Smith fabricated a custom air-to-liquid intercooler with its own pump and radiator system; subsequent track testing revealed the intercooler was good for about 35 horsepower. Preston reins in the supercharger with an MSD boost retard; an MSD 6AL two-step spark intensifier is also employed, along with the stock (albeit indexed) distributor and Moroso heli-wound plug wires. An ACCEL power processor helps out the on-board computer system. The estimated power is approximately 550 hp at the flywheel.

That kind of power will cripple a stock driveline in short order, so the stock automatic was replaced with a 700-R4 modified by CJM Racing Transmissions utilizing B&M internals and an Art Carr 10-inch, 2500rpm stall-speed non-lockup torque converter. It all ties into a 3.54:1-geared Dana 44 which, even equipped with Moser axles, became the car's Achille's heel.

"At New England Dragway last summer, I jumped down into the low-1.5 second 60-foot times", Preston recollected. "Normally, that isn't a problem, but with a 3500-pound car, it is. I popped the spider gears inside the housing because the axle tubes were flexing. We're in the process of fitting the car with a nine-inch differential with 3.70 gears and a Detroit Locker and 35-spline axles. I even had to brace the back of the housing!".

Smith also intends to send the entire intake system-air plenum, runners, lower intake manifold and cylinder heads - to Extrude-Hone, where the whole package will be port-matched. "It should be good for about 20 hp" Preston noted. "It doesn't sound like much, but on this kind of car you can't achieve big power gains in a single step. All the easy things have already been done". The extra ponies should be enough to drop the 3745-pound (with driver) machine well into the 10-second time zone. It's already turned in a best of 10.975 on D.O.T.-approved 275/60-15 M&H tires; changing to slicks has lowered the times to 10.86, although the speed drops off a bit (125.3 versus 126.7 mph) "because the D.O.T. tires are more flexible, and tend to 'grow' a bit more at the top end...."

...."I did test it once at the track without changing anything", he pointed out. "With a full tank of gas, it weighed in at just under 3850 pounds. It still turned 11.7 seconds on the 255/50-16ZR Bridgestone RE-71 tires, although I did have to retard it way back for the street gas".

Setting the car up for the track is a simple operation; Preston removes the front sway bar, sets the adjustable front shocks to "full soft", and adds a pair of 1-1/2 inch spacers to each rear spring to keep the Camaro from squatting under acceleration. The car runs a full exhaust - from Hedman 1-5/8-inch primary tube headers and Burns 2-1/2-inch merge collectors to dual 2-1/2-inch exhaust pipes and Sonic Turbo mufflers - at all times.

It also runs cruise control and a 150-watt Fosgate "punch system" stereo, attesting to its street nature. "Thats what really attracts attention", Preston admits. "This is the most streetable fast car most people have ever seen - they look in back and see those big 12-inch woofers and can't believe that it goes as fast as it does at the track in essentially the same trim. I get 10 seconds in the quarter mile - and 17 miles per gallon out on the highway"...

- Super Chevy March '94

 

wow 3750+ lbs?? what is that thirdgen made of, lead??

 

You and I both know forced induction is neither cheap nor easy. Im talking about cost/benefit analysis. Doing things on a budget and getting the most for your money.

You can buy 1 widget for a $1. You can buy 4 widgets for $3. And you can buy 400 widgets for $150 and save a hell of al ot of money. But $150 is a drastic price increase from $3 and prices it out of budget racers. This is addressed to both you AND Orr who keeps talking about building 383's and LSx engines. The NA 350 is not a better engine than a turbo 305 or a NA LS1. But it's a hell of a lot easier to put in a thirdgen. And I keep hinging on easy because not everyone has the knowledge to swap in a big block or a 383 stroker. It requires attention to certain details that not even most of the people on TGO are properly aware of. If you lack the knowledge to do it, you can learn but a lot of people will just end up farming it out to someone else for a fee. If not, they still usually end up having to buy equipment to get it done.

My issue with turbos is even a cheeeep ebay turbo setup is gonna set you back at least 2 grand by the time you're done getting it running. If your uncle died and left you a perfect turbo set up hiding under a burlap sack in his barn or you got a turbo kit that fell off a truck, that's fine, but building a turbo thirdgen requires a fair amount of tools and expertise and a decent amount of money. Saying that the 305 is worth keeping because a very small minority of hot rodders are capable of putting a turbo setup on it for a moderate chunk of money invested and make it faster than a 350 is like saying the 2.8 v6 is a great engine because you can turbo it and make it faster than a 350. It's true, but not exactly a fair comparison due to the cost of entry (both monetary and knowledge).

The 350 is not the best engine. It's merely the best cheap one. My next build will, I hope, be a Dart SHP 400. I dont see the point in messing around with regular 350s anymore, but for someone coming up from a 305 on a budget, especially if it's an LG4 with the dished pistons, a 350 is, in my opinion, the best option.

 

What get's me about that article, not that I'm knocking Preston's old setup, but he was running tens and trapping 127-mph in that heavy of a car with only 16-pounds of boost and 30lb injectors with a 305. Best I did with only 30lb injectors was mid elevens before the injectors went static, and I was running nowehere near that weight. Just goes to show what can get accomplished with the right suspension setup...

 

i'm gonna try my hand with a turbo 305 i got 400 hp out of a 4 banger with a turbo .

 

I highly doubt just suspension will make a car run that many mph over what you may have been running. I would guess he had an FMU and likely increased pressure a crap ton. At 3450lbs, I was mid 10's at 127 with a 400whp 383 + a 150 shot nitrous.... So figure 500-520whp. At 3700+ thats got to be near 600whp. On 16psi with a 305? That is getting it done.

 

Haha, I was being sarcastic with that suspension comment (should have used a rolling eyes smiley lol). Even with a low sixty foot, he may ET well, but would still need the horsepower to get to that mph. He was making approximately 475-RWHP (550-FWHP) with that setup as per that article, at 3700+ pounds of weight and at 16 pounds of boost that is definitely getting it done...

 

... come to think about it;

Injector Rating x # of injectors x Duty Cycle / BSFC = Maximum Horsepower...

30 x 8 x .9 / .6 = 360

I'm almost ready to call bs with Preston's old setup myself...

 

maybe they failed to mention the 200 hp shot of happy gas on top of it .lol

 

Could very well be. That is the problem with these old articles that were written before the internet, there is no real way to document them correctly, it is all based on hearsay. I know for a fact that my 30lb LC2 injectors were done at around 12-psi, in fact they were going static at that boost pressure level, and I only ran 11.5x @ 117 with those injectors. There might be more to Preston's story than meets the eye, either that or Super Chevy fudged the numbers to sell some magazines because it was a cover story...

 

I figured you were being sarcastic with the three periods but I wanted to be sure I've seen 24lb injectors support 350whp and 30's support near 400whp. Most guys in the 400-450whp range run 36-42's. I think my buddy's 406 made 521whp with 42lb injectors turned up in pressure abit and its over 80% duty cycle.

521whp at 3400-ish lbs went 10.4 at 132. So thats about the power it would take to run 127mph at 3750lbs.

But oh well, no one is denying that boost can really wake up a 305.