The Truth About The Small Block Chevy 305

hey guys rap mayor here and today we're going to talk about the small block Chevy 305 is it good or is it bad a lot of people have different opinions on it so let's go ahead and jump right into it [Applause] so the truth is the thing sucks that's all you need to know about it no no I'm completely kidding but when people think about the small block Chevy 305 they're probably thinking about that middle-aged man with a mullet and the third gen Camaro trying to do a burnout at the Fourth of July party but really they just spin one wheel because they don't have a posi and the thing only makes 190 horsepower that's usually what people think about when they think about the small block Chevy 305 that doesn't necessarily mean it's a bad engine though so small block Chevy 305 was introduced in 1976 and that production lasted until 1998. basically the small block Chevy 305 was introduced for one reason and one reason only Chevrolet or GM as a whole was trying to go more towards an economy route so they were trying to make the 305 the largest engine that they would produce basically they were trying to phase out the V8 in favor of a V6 the problem that this led to was that the V6 made dismal power and the 305 unfortunately well it was still a small block Chevy it's still honestly a reliable engine it just did not make the power that Chevrolet needed to actually keep up with competition it was not a very good fit for what they were trying to replace so we're going to get on to the elephant in the room why hasn't the 305 ever been considered much of a Performance Engine or really worth building for performance well there's a few different reasons so some people might think that well the 302 and for example of 305 they're pretty similar in displacement why is the 302 so much better or why is you know why do people even consider the 283 a better engine than the 305. well the reason that the 305 has never been a solid Contender for making a bunch of power is because of its design it had a 3.48 inch stroke which is the same as the 350 however it had a 3.736 inch bore and that is actually smaller than a 265 small block Chevy basically the problem with such a small bore is that you can't put a very large valve in the heads it will run straight into the cylinder wall and the earlier 305s 1976 to 1979 came with such a small intake valve that really you're not getting any horsepower out of it it's 1.72 inch intake valve and then the performance version had a 1.84 inch intake valve in the slightly later years but the biggest that you could put in is a 1.94 inch intake valve and that is actually an okay size I would say it's the minimum for making an engine that you can actually have a little bit of fun with but it is nowhere near what I would consider super aftermarket or something that you would could make a bunch of Power with at least naturally aspirated my Corvette over here for example the yellow one makes about 400 and something horsepower roughly in there and it does have 194s or 1.94 inch intake valves but it's on a 400 so it's got that going for it this so that is the biggest caveat because at the end of the day an engine is an air pump the more fuel and the more air that you can put into it the more that you're going to get out of it so having this smaller valve restriction is a big deal for when you're trying to make all-out maximum power even though we had a smaller valve size and a smaller bore size there's one thing to be said we still managed to get those better fuel economy numbers because of the 305's limitations sure it didn't make much power 160 horsepower at its worst 230 horsepower at its best but it was the first engine to actually introduce fuel economy to a V8 19 to 20 miles per gallon in the city and 26 to 27 City my Duramax doesn't even get that so I would say it's kind of like a precursor to what we would eventually get with the ls in terms of fuel economy didn't make any power so if you're curious what 305 you have you can actually have a high output 305 or a Vortec 305 the vortec 305s are a little bit more rare they're technically codenamed Vortec 5000 but if you pop off your valve cover if you have a Vortec 305 the end casting on there as seen here will be 520 so it'll be the last three on the casting number on the head on the head under the valve cover for the ho which is a little bit earlier the 80s basically 305s you could either see 416 or 601 those are the ho heads these engines the for example the Vortec 305 had a 9.4 to 1 compression ratio while the h0305s in the 80s had a 9.5 to 1 compression ratio that's because both of these heads or I should say all three of these heads that were used on 305s just in general had a smaller combustion chamber than the rest of the 305s so this introduced a you know nine and a half to one roughly compression ratio versus the other 305s 8.6 to 1 compression ratio it was about 58 CC's now don't get me wrong the 305 heads were still not as good as the better 350 heads for example earlier years you had the camel humps in later years you had the vortec 350 heads you've got larger Runners with the 350 heads you've got a larger valve size with 350 heads it is an overall better head and the problem is is that that ho and that Vortec 305 made its compression ratio through the reduction in combustion chamber size so basically if you try and put a 350 head such as camel humps or the vortec 350 heads on a 305 you're more than likely going to reduce the compression if it's a Vortec 305 or an h0305 and this is because the heads on a Vortec 305 and an h0305 got their compression through smaller combustion Chambers versus the earlier heads the camo hubs and the later heads the vortec 350s so those heads have a 64 CC chamber while the Vortec 305 and the h0305s have a 58cc chamber so if you have an ho 305 or a Vortec 305 if you bolt on a better set of heads from a 350 or 327 from earlier years if you bolt on just a better set of heads or even an aftermarket set of heads more than likely it's going to have 64 CC Chambers and those 64 CC Chambers since it is a bigger combustion chamber than the 58cc it is going to drop your compression quite dramatically from that nine and a half to one best way to combat this is by putting a steel shim head gasket on it however you're probably still only going to get it up to just barely the 91 Range but that is one thing to be a little bit leery of is that if you're trying to make higher compression and you want to change the heads it is going to cost you a well a bit of compression for those better heads now at the end of the day do I recommend building a 305 well it really depends on what you're trying to do with it the 305 is not a bad engine but it does have its caveats and you do need to look into that if you're trying to build one you're going to understand the limitations of what you're trying to go after it's not a bad engine but is it going to fit the needs for what you want is it a go into town rig or is it a street strip car if it's a street strip car find a 350 find a small block Chevy 400 or even a 327 they're all going to be better options than a 305. if you just want something reliable to go to and from to work or if you already have the engine sure a 305 is still a decent starting point it doesn't need to be fast but you need to understand those limitations before you go all out with that engine you need to understand that you're going to not make as much power and spend the same amount of money if not more trying to chase that power if you you do want to build it for that aspect so really it just depends what you're trying to do now for the fun of it why don't we go ahead and watch a built 305 and see what it can do [Music] [Applause] [Music] anyways guys I hope you did enjoy this information as a 305 was something that I've been wanting to talk about for quite some time it is usually an engine that just gets swept under the rug or considered garbage just in general that's not necessarily so you basically just need to understand the limitations of what you can do with it and go from there so if you did like this video please comment like And subscribe and as always you guys have a great day

Channel: RatMaro

Views: 40,750

Keywords: Small Block Chevy 305, Chevy 305, Monte Carlo SS, G Body 305, Elcamino 305, 305 V8 Montecarlo, 305 Camaro, 305 Corvette, Small block chevy, SBC 305, SBC 327, SBC 400, Small block 305, 305 V8 Elcamino

Id: QdUrJVVbTc8

Length: 9min 38sec (578 seconds)

Published: Tue Jan 17 2023