Stroking a 305

[fleming442]

I think it's an inch of deck height....

 

[bob64]

I think it's an inch of deck height....

An a whole lot of width an 150lbs

 

[fleming442]

But, MORE POWER!

 

[Clutch]

I started laughing when l seem your last few words regarding 307 vs 455. 455 is a monster compared to a 307 or 350 olds block, you can almost tell the difference in how the frontend sits. Lol

Lol and it's bolt action but it's painted black and jammed in there with all the 307 accessories on it even a/c and cruise control it's just 4" wider and about 2" taller lol never know the difference 😗

 

[Clutch]

I think my point was the average Joe won't know

 

[bob64]

I think my point was the average Joe won't know

Well the women keep saying l'm average! Lol!

I get your point. I've had afew of them back when you couldn't get aftermarket parts for them, an they were stump pullers.

 

[Clone TIE Pilot]

FWIW I started fixing up my 305 in my Cutlass wagon which had been rebuilt by the previous owner and had about 35,000 on it. I added a Crane 266 cam that had .440 lift, air gap dual plane intake, Edelbrock 600 carb, Pertronix HEI internals upgrade, headers and a single 3" exhaust. The lower torque output of the smaller engine was compounded by the crazy 2.41 gas mileage rear gears but it still ran ok, turning 15.90s @ 88 mph in the 1/4 mile at sea level, near 2 seconds faster than in stock form which was 17.70s at sea level. Remember, the 305 was a "performance" motor used in IROC Camaros to Monte's and for a small motor with lousy flowing parts it actually does ok with some slight upgrades. With stock heads it's really limited to just how much power it can make, the TPI intake, heads and cam really woke up the motor for the IROCS.

In comparison in high school I had a Nova that came from the factory with a 307 SBC. With similar upgrades and a set of freshened up camel hump heads with the factory 2.73 gears it was slower at 16.0 in the 1/4 because the 305 makes more torque than a 307. My guess is that's why GM went with that bore and stroke combo for the generic Chevy small cube motor. All of my performance builds have had 406 SBC's and one of those eventually replaced the 305 in my wagon. The 305 got about 21 mpg at 65 mph whereas the 406 with mildly ported factory 400 heads, a .510 lift cam that was a Comp XE268 with 1.6 rockers, and the same intake, exhaust system, and 2.41 gears ran 14.20s @ 97 mph in the 1/4 and got 18 mpg. Eventually I swapped in a 3.42 rear axle and it ran 13.60s in the 1/4. Cubic inches makes a big difference.

So, really a 305 isn't that bad of a motor, but... Another project I have is a 73 Nova restomod project with a lot of planned hidden upgrades. The car was originally a 350 2bbl./ 3 speed, but I've decided to clone the '73 "performance" 245 hp 350 with stickers, intake, carb, etc. Under all the stickers and orange paint will actually be a disguised 406 with the same 268 cam that was in the wagon. On the outside, unless someone looks at the harmonic balancer you would never know it isn't a 350. As others have said you can easily clone the 305 with a bigger motor under the blue paint and such. A rebuild will essentially cost the same and you'll end up with a bunch more torque and horse power even with mild parts, and if you decide to upgrade to even better parts down the road the power potential is even greater and less limited.

Good luck with the project!

Small bore motors generally have more complete cylinder filling which helps with quench and more complete combustion which leads to better MPGs and lower emissions. While larger bores allow for a larger air/fuel charge to make more power. However, they generally don't fill as completely as small bores which results in worse quench and less complete combustion which means less MPGs and more emissions. When a cylinder is filled more completely, the charge is better mixed with less lean spots that cause detonation. When a cylinder is less completely filled there are more lean spots and higher tendency for detonation. Its one reason why 80s 305s tend to have more CR and spark timing than most 350s of the 80s, they have better natural quench to put it in simple terms. It is also one of the factors why small CID engines often have better power to displacement ratios than large displacement engines.

Over on Thirdgen, there are several guys making 300 HP with 305s with 059 Vortec heads and cam swaps, even on TBI and CCC. 305s are decent engines but 350s do have more potential power available.

 

[oldmansmonte]

Damn. You guys are the reason there's hardly any unmolested gbodys out there anymore! Always telling people they need to 'upgrade' stuff because the factory stuff sucks. Fancy suspension parts, brakes, engine swaps, transmission swaps, gutting stuff, etc.

While I would 100% agree that stroking a 305 is over the line, it's not always about having the 'best' of everything available.
Nothing wrong with having a cool unmolested stock ( or minor upgraded ) Gbody. Easy to work on, easy to know what parts you need to fix stuff, gets tons of thumbs up at car cruises etc.

Now if you want REAL performance, then yes, you gotta unstockify your Gbody!

Listen I love G-bodies. All of them. They're among the last "real cars" made. They're are so many things they also modernized from the previous generation of rwd cars and the last great 2 door cars that aren't sports cars. But who wants to go through the trouble of finding and paying for(now much more than ever) a nice G-body only to be saddled with a 3.8 2bbl, or a 4.3 or at best a 185 hp 305? The cars were hampered by standards and technology at the time. I respect the occasional guy who keeps it hardcore all original, but with the interchangeability of parts gm is known for, ease of working on these cars and incredible aftermarket support is why they continue to be popular. It's expected people are going to modify these cars.

 

[MrSony]

Damn. You guys are the reason there's hardly any unmolested gbodys out there anymore! Always telling people they need to 'upgrade' stuff because the factory stuff sucks. Fancy suspension parts, brakes, engine swaps, transmission swaps, gutting stuff, etc.

While I would 100% agree that stroking a 305 is over the line, it's not always about having the 'best' of everything available.
Nothing wrong with having a cool unmolested stock ( or minor upgraded ) Gbody. Easy to work on, easy to know what parts you need to fix stuff, gets tons of thumbs up at car cruises etc.

Now if you want REAL performance, then yes, you gotta unstockify your Gbody!

Dude, stock G bodies are piles of crap. They really are. Flimsy frames, poor build quality, vastly under engineered and under powered. No to mention they handle like a fat guy on a wet trampoline in stock form and lord help you if your car wasn't undercoated from the get go.

We are the reason there are still G bodies to modify. If it wasn't for the people on this forum, a lot of these cars would've been crushed a long, long time ago. Hell, 10 minutes after purchased my Regal and left, some guy and his kid showed up to the p/o's place to buy it with intentions of turning it into a stock car. It had 84,000 miles (at the time in 2014), BONE STOCK, no rust, original down to the radio. The heat, AC, power antenna, cruise, all still worked. Poor thing would've been gutted and destroyed if I would've stopped on the way there to pee. We save these cars from that fate. That's why this forum exists.

All we're trying to do is offer our input. Some guys have been on this site for almost a decade or more, and a good chunk of 'em saw these cars roll out of dealers with less than 20 miles on them back in the day. We've all seen it 100s of times before; Guy has a car, wants to "keep it numbers matching" and rebuild the gutless turd that the car was born with, only to get that idea shot down. Why? It's simply a waste of time and money. No one cares about a numbers matching 305, NA 231/4.1/307/diesel G body. If it ain't a 231 with a big ol hair dryer strapped to the front, a 2+2, or a 442, people besides us just see another cheap derby car.

And it's not that we're after "REAL" performance, we're just after performance. These cars aren't Chevelles or Camaros or Chargers. They're G Bodies. Sloshy, slow, dumpy, brick-shaped G bodies.

In the end, it's your car. We can't force you to go one way or another, we're just offering advice from experience.

 

[bob64]

Fat guy on a trampoline, oh the stories my kids could tell about that one!

Oh an my olds and monty say "ouch" lol