Why culturally is the 302 Ford regarded as "potent" and the 305 Chevy regarded as anemic? I did a bit of general research and the engines appear to have been roughly comparable for hp/torque in the mid-eighties. I'm sure the aftermarket support is different and the factory development appears to have differed significantly. Is there something I'm missing or is this just anecdotal application perception?
Bore size is one thing. The Ford has 4.0" bores.
Also, I don't think the 305 ever came with a roller cam. (EDIT: OK, it did, but it's nowhere near as prevalent as the 302 with the roller cam.)
Finally, the 305 was never "top dog" of the Chevy lineup, like the 302 was for Ford. Chevy wasn't ever really going all-out with it.
Plenty of 305's had roller cams, but they're still 305's. Tiny bores so you can't use decent sized valves, etc. i sold one once for $125 and thought i ripped him off.
What kinda power can you make on a 305? Could it be made a worthy engine for the drag strip and daily driving?
Patrick said:Plenty of 305's had roller cams, but they're still 305's.
I looked it up and you're right. There was a transition to roller cams around 1987.
That said, you won't run into too many 302s with flat tappets, at least not in a Mustang. That's early, early 1980s stuff in a Mustang.
In reply to stroker :
Bore. The SBF has a 4.000" bore and the SBC has a 3.736". The smaller bore shrouds the valves, which affects airflow.
Also the SBC came from the factory in some pretty hot configurations. The 305 only came in pedestrian forms.
_ said:What kinda power can you make on a 305? Could it be made a worthy engine for the drag strip and daily driving?
The problem with the 305, is that you can spend the exact same money on the exact same parts in an extremely easy to find 350 and make more power.
Interesting. While everoyne else was googling, I was reading up on this because I have had this question as well. It seems that they are very comparable and the main limitation between the two is this: The ford has a ton of head options available, the chevy has some good heads available, but *most* heads are designed for the 350 and wont work with the bore on the 305. The ford has the downside at higher power levels where the block can crack.
This seemed like a pretty methodical approach:
https://www.hotrod.com/articles/302-ford-vs-305-chevy-part-1-intro-baseline/
https://www.hotrod.com/articles/5-0-fistfight-pt-2/
https://www.hotrod.com/articles/5-0-fistfight-part-3-carb-combos/
https://www.hotrod.com/articles/5-0l-fistfight-part-4-storm-rages/
I think the main difference between them from a performance standpoint is that the 305 has a smaller bore size which ultimately limits valve size.
ProDarwin said:Interesting. While everoyne else was googling, I was reading up on this because I have had this question as well. It seems that they are very comparable and the main limitation between the two is this: The ford has a ton of head options available, the chevy has some good heads available, but *most* heads are designed for the 350 and wont work with the bore on the 305. The ford has the downside at higher power levels where the block can crack.
This seemed like a pretty methodical approach:
https://www.hotrod.com/articles/302-ford-vs-305-chevy-part-1-intro-baseline/
https://www.hotrod.com/articles/5-0-fistfight-pt-2/
https://www.hotrod.com/articles/5-0-fistfight-part-3-carb-combos/
https://www.hotrod.com/articles/5-0l-fistfight-part-4-storm-rages/
The problem with that whole series is that they had to choke down the 302 to "match" what was available for the 305. That's kinda the whole point, there's way better stuff available for the 302 (sometimes even at better prices than the restricted stuff), so use it!
And the 305 has a comparatively long stroke (3.48) vs the 302's short stroke (3.00), limiting revs.
_ said:What kinda power can you make on a 305? Could it be made a worthy engine for the drag strip and daily driving?
I think it's the June 86 issue of Hot Rod has an article on building a 305. I'm quite certain it's 86 and think the monto was June.
Javelin said:ProDarwin said:Interesting. While everoyne else was googling, I was reading up on this because I have had this question as well. It seems that they are very comparable and the main limitation between the two is this: The ford has a ton of head options available, the chevy has some good heads available, but *most* heads are designed for the 350 and wont work with the bore on the 305. The ford has the downside at higher power levels where the block can crack.
This seemed like a pretty methodical approach:
https://www.hotrod.com/articles/302-ford-vs-305-chevy-part-1-intro-baseline/
https://www.hotrod.com/articles/5-0-fistfight-pt-2/
https://www.hotrod.com/articles/5-0-fistfight-part-3-carb-combos/
https://www.hotrod.com/articles/5-0l-fistfight-part-4-storm-rages/
The problem with that whole series is that they had to choke down the 302 to "match" what was available for the 305. That's kinda the whole point, there's way better stuff available for the 302 (sometimes even at better prices than the restricted stuff), so use it!
If you read it, in part 3 they did take advantage of this, and the Ford made 415 hp to the Chevy's 376
Vortec or similar heads fix some 305 sins but then the intake options are poor if you want port efi. A Vortec 305 with TPI and an MS seems like a great platform to build on but I think that the viable base manifold isn't available new anymore.
In reply to pres589 (djronnebaum) :
The Vortec TPI base is hard to get and expensive but you can get an Edlebrock Pro Flo in Vortec flavor.
So did F5000 use a 350 block rather than the 305 block? Otherwise, why wasn't the Ford used?
In reply to stroker :
My estimation is that it was probably a 302 Chevy. Which is a 4" bore block like the 350 but with a shorter stroke.
Daylan C said:In reply to stroker :
My estimation is that it was probably a 302 Chevy. Which is a 4" bore block like the 350 but with a shorter stroke.
Yep, sounds like you nailed it. Extensive confirmation on Wikipedia.
You want a Chevy 302.... now that’s and engine.
The original Chevy 302 is 327 with a 283 crank. Later they went with the bigger journal block.
And the f5000 engines were 302 based. Later f5000 and single seat can am might have been 350 based with a smaller stroke crank.
stroker said:Why culturally is the 302 Ford regarded as "potent" and the 305 Chevy regarded as anemic? I did a bit of general research and the engines appear to have been roughly comparable for hp/torque in the mid-eighties. I'm sure the aftermarket support is different and the factory development appears to have differed significantly. Is there something I'm missing or is this just anecdotal application perception?
One can conjecture about Ford heads traditionally sucking so the 5.0 was a breath of fresh air, while the 305 was following a long history of much better small-blocks, or the Mustang being a better drag platform than the Camaro, or any of a bunch of other factors, but my take is that the Ford intake manifolds were way better, and there was a better upgrade path thanks the the mass airflow engine management, while the F-bodies were stuck with the abomination of a TPI intake manifold and no good way around that, and speed-density meant that modifying the engine in any way led to poor running.
We're spoiled today. Aftermarket intake manifolds or the ability to get into the computers didn't really exist in the 80s. Cam companies were coming out with "computer friendly" cams, which meant that they tried to make cam profiles that would work with the existing tunes in the PROMs, which generally meant that they also had roughly the same specs and made roughly the same power. By the time the aftermarket started coming around with intakes that could flow, they were mostly made for Fords, because they had mass air management and they would actually do something useful.
I grew up reading the magazines when those were new cars, and they usually pitted 5.0 Mustangs against 5.0 Camaros, at first because the 5.7 was a Corvette-only engine, and later because the 5.7 was automatic only and they wanted to compare manual trans cars. In reality, stock for stock, they were pretty closely matched.
SkinnyG said:And the 305 has a comparatively long stroke (3.48) vs the 302's short stroke (3.00), limiting revs.
Not so much as you'd think. The 3.48" stroke is 88.4mm, which is almost exactly halfway between the 84mm and 90.7mm strokes of the Honda S2000 and S2200 engines. It is also almost identical to the the Honda K20 (88mm) and B18 (87.2), including the Integra Type R....
The 302 (either make) by contrast is 76.2mm, which is also the same stroke (and bore!) as the 2.5l Iron Duke engine.
On any small block V8, head flow and valvetrain limit revs. Even with 400-stroke cranks and larger, the bottom end isn't the RPM limit, headflow or keeping the valvetrain from grenading are. This is why the LS and iron block variants rule: their heads flow and flow and flow, and the semi shaft rocker valvetrain is pretty stable.
A Ford 302, in pedestrian guise, is a lame-o, gutless, leaky turd. Lousy heads, generally bolted to a torque sucking Ford built automatic.
An 80's 5.0 Ford is a massive step up.
Talk about stroke length, or whether an engine is over or undersquare in terms of limiting revs or where you make power are generally misinformed. As Knurled said it's your top end that effectively 'limits' where you make power and thus how high you bother to rev to, at least in the gasoline world.
Stroke length by itself doesn't tell you enough. Stroke has a big impact on piston acceleration at a given RPM, but without also knowing the bore size you can't even ballpark how much of an issue that is because you don't know how heavy the piston is. You can also affect this with rod ratio (piston compression height or block deck height differences at a given displacement) but making the rod longer also adds weight that has to be accelerated so that's not free either unless you're taking equivalent weight out of the piston. Oversquare engines sound like a nice idea in general but somewhere out there is probably an oversquare diesel engine with 10 lb steel pistons that will self-destruct at 2700 rpm, so pretty much everything is a generalization or oversimplification. Bore diameter does effectively limit valve area so while you could make a super long stroke engine work at high rpm by making tiny cylinders with light pistons (in cone shaped cylinders!?) , those cylinders wouldn't have enough valve area to flow commensurate to their displacement unless they were side ports like a 2-stroke. There are technically a huge range of ways to build the engine, but only a narrow range of it actually makes sense to do in the real world. When you combine all the factors it starts to make sense why all the engines fall into sort of a narrow range, and within that range you are generally more limited by headflow and valvetrain than you are by the actual bottom end of the engine.
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