Help me understand 5.0 disparities

[Soundmound]

Something has been on my mind and I need answers. Why is the 5.0 302 Ford venerated and 5.0 305 Chevy denigrated? It's just been smoldering in the back of my mind for a minute and I want to hear your opinion or facts.

 

[HotWheelsBurban]

So far as l know ( from what I remember my blue oval friends saying) the Ford 302 was built as a performance motor for the most part. Even the current generation uses that size.
Whereas the GM 5 liter engines(305, 301,307) were set up more for economy, so designed and tuned a lot different.
The only 305 I have experience with is the 2 barrel carb one in the '81 Sierra C15 longbed. That truck would do everything the '78 Sierra Heavy Half would, with a 350(we never were brave enough to try the travel trailer on it though!). It would easily get and hold 75 on the freeway, and we towed several cars on a flat trailer with it. And these were heavy stuff like a '65 Impala, '67 Riviera, '70 Bonneville; real boat anchors.

 

[DoubleDingo]

I only have experience with the 302 in grandpa's 71 f100. That little truck could haul goods, a$$, and got decent mileage doing it.
I thought Crusty Biscuit had a 350, but it has to be a gutless 305, as I tuned it the best I could and it was still a gutless pig.

 

[DoubleDingo]

If I had a choice, I'd rock a Ford 302 over a Chevy 305 any day.

 

[RecklessWOT]

Believe it or not (as much as Ford really would like to pretend it's not true) the 302 is actually only 4.9 liters in displacement lol

But yeah, from the start the Chevy 305 was designed as an economical fuel saving engine. They essentially took a 350 and decreased the bore size if I remember correctly. The Ford 302 was designed to be exactly what it is, a decently punchy little smallblock. As much as I don't love Ford, I will agree the Ford 302 is a much better performing engine than a chevy 305 (though it's hard to beat the reliability of an SBC). Maybe it's the shape of the combustion chambers of head flow or cams or whatever the difference is, but a 305 is a wet blanket in comparison, the 302 is actually more comparable to a 350 power-wise. I really don't know specifically what the difference is, but obviously an engine is wayyy more than just displacement. Only Ford I ever owned had a 302 and it didn't feel underpowered like a 305 does, that truck actually moved out pretty decently. Just everything else about it was a total headache lol

 

[75gmck25]

The Ford 302 is in the same family as the 221/260/289. The 260 and 289 were used in the Falcon Sprint and the Mustang, and there were several performance variations, including the high performance 289 used by Shelby in the Cobra two-seater and the Shelby 350 Mustang. That engine family got an early reputation for performance, and it was carried forward to the Boss 302 Mustang in 1969. Both Ford and Chevy produced 302 CI engines for Trans Am racing, and they were great performance engines.

The 305 is a decent engine, but the Chevy 327 and Chevy 302 in the Z28 were known as performance engines. I think all the 307s were 2 barrel economy engines, so nobody seems to want one.

 

[Ricko1966]

302 ford is same bore and stroke as 302 chevy 4.0 bore 3.0 stroke good for high rpm use and with the 4 inch bore the valves aren't shrouded and there is room for bigger valves. I'm doing all this from memory so I know I'm not exactly correct on the 305 bore. 305 bore is I think 3.76 and stroke is 3.48 better for torque as the power stroke happens over a further distance,a nice slow burn,not as good for rpm also with the smaller bore there isn't room for big valves and since the valves are up against the cylinder wall the sides of the valves are shrouded, further reducing flow. As a good torque motor I have no problem with a 305,with a hot rod I want as much bore as much stroke and as big of valves as I can make fit.

 

[SquareRoot]

Something has been on my mind and I need answers. Why is the 5.0 302 Ford venerated and 5.0 305 Chevy denigrated? It's just been smoldering in the back of my mind for a minute and I want to hear your opinion or facts.

Apples to oranges. The 302 in the 69 Camaro was a screamer. You can't judge a book by its CI.

 

[SquareRoot]

Something has been on my mind and I need answers. Why is the 5.0 302 Ford venerated and 5.0 305 Chevy denigrated? It's just been smoldering in the back of my mind for a minute and I want to hear your opinion or facts.

The 307 beat them both and was an absolute pig.

 

[fast 99]

305 was designed at the start of smog restrictions and installed in relatively heavy vehicles with high gearing. Low compression, asthmatic camshafts with small valve heads and 2 bolt mains didn't help. A 305 could be made to scream like any engine could, but it was an oddball with specific parts. Only items directly interchangeable with other small blocks were the rods and crank. No one wanted to mess with it when 350's were all over the place. I took out a lot of 305's and installed 350's. 305 core was next to worthless.

Around the same time there was the 307 and 262 both smog grocery getters.

It's not the CI itself. It's the intent of the original design. The GM 302 was a performer.

302's Fords on the other hand had decent heads with generally higher compression. Especially the K and G code motors. They were plentiful, revved to the moon. Some had 4-barrel carbs, and available in lighter vehicles geared for performance. Later on [of course] they were strangled by smog as well.

305 is not alone in the "don't want for performance category". Almost all 400's from every brand were dogs from the factory. Emissions killed HP.

 

[TotalyHucked]

As stated, it all comes down to the overall design. The Chevy 305 has super small bore vs the Ford and that right there seriously limits power potential. The 305 is a boat anchor and never will be anything more. Even with a healthy cam and better heads, the 305 can only make so much power, I think 300ish about all you'll get without boost. A Ford 302 is easy to get to 500hp, but you've gotta get an aftermarket block at that point cuz they'll split right down the valley.

I've had both, first an '87 IROC with the last year carb'd 305 "HO" That car couldn't pull your hand out of your pocket with the 700R4 and 2.73s. Had a buddy in HS that put smaller chamber heads and a bigger cam in his IROC with a 3.73 gear and our other buddy's '94 GT Mustang with nothing but 3.73 gears would absolutely curb stomp him.

I also had a '94 and a '95 Mustang GT with the 302 in them. They're fun little engines that respond well to upgrades, gears being the best bang for the buck. The '94 had an E-303 cam in it, 5-speed with 3.73 gears and was a super fun street car. It helps that you can get blocks, all kinds of different heads, cams, stroker kits, etc for them. There's almost nothing for a 305 and there's a reason for that. Someday I'd like to get another '94 GT and build it up with a rowdy 331 stroker.

Here's a good article about the 305:

305 Engine Build Questions & Much More - Car Craft Magazine

This time in "What's Your Problem" we dive into why it's is/is not a good idea to build a 305 engine and many other topics readers send in. Only at www.carcraft.com, the official website for Car Craft Magazine.

www.motortrend.com

 

[GTX63]

The size of an engine has little to do with performance, or we would all be running 460 Fords.
They can be the same size but share nothing else, ie cam lift, valve size, head breathing capabilities, carburation, as well as the quality of internal design.

 

[idahovette]

^^^^^^^^^^^^NO NO NO NO NO !!!!!!! if that(displacement)....why not a 472 or a 500 Cadillac?????

 

[Bextreme04]

The replacement for displacement is RPM(actually it's boost... but you get the idea). The reason a 305 is not well liked is because it has a smaller displacement than a 350, but gets to that displacement with the same stroke and a smaller bore. This combo means it really has the same RPM potential as a 350, but less power potential. They make decent torque down low, but have the same rotating strain as a bigger displacement 350 at high RPM.

The ford 302 gets there in the complete opposite way. It has the same bore as a 351, but a shorter stroke. This means that it has less grunt down low, but can spin way up in the RPM range to make good HP at the top end without putting so much strain on the bottom end of the engine. A 289, 302, and 351W all have the same bore(4.00")

 

[TotalyHucked]

Also, if we're talking apples to apples in either 80s or 90s spec, neither of them had great heads (speak in Mustang vs Camaro, not truck) but the 305 FLAT. RAN. OUT. OF. BREATH. at 4500. Carb'd, TPI, TBI, they all were done at 4500, nothing but noise (or windowing the block ) after that. The Mustang would rev to 6-6200 and made power well past 5.