305 Bad Mouthing

I just thought I would go off on people who bad mouth the 305. It does not upset me so much as it saddens me to see people doing this. I believe that if you say bad things about the 305 then you might as well be saying them about the 350 because as anyone should know, they are the same engine with different bores. Now just because GM made the mistake in using the 305 strictly as an engine with good economy and not for performance doesn't make it junk. It is just as easy to build up a 305 as a 350 and it is cheaper too. The only bad thing GM did to give the engine such a bad reputation was to put bad flowing heads and manifolds on it. There are a lot of performance parts out there for the 305 and all it takes some looking to find them. You can find stroker kits for the 305 to stroke it out to a 335 and World Products makes a great set of heads for the 305 as well. Combined with a good cam and intake, It wouldn't be uncommon to see 400hp. If anyone is interested in this kind of performance, I found a great website that appreciates the 305 as much as I do and I think it deserves a look if you are in the dark with the 305. http://www.goingfaster.com/spo/modthel03.html

yeah i take a lot of crap because everyone says i will blow my engine running a 135 hp wet nitrous shot on a 305. the 305 isn't any weaker than the 350.

Hmmm... Dont get all pissy now. Hard rock motor.... Hmm hard as a rock to make power from basic boltons. Swaping the whole intake manifold isnt a basic bolton. Maybe the throttle body injection. Most ppl give crap for that simple fact. Put basic bolt on's on a 90 mustang lx.... or an 5.7 iroc.... i/h/e some ud pullies timing advance gears. The 305 isnt that bad of a motor.... but why start with something that you have out to change a whole intake mani or heads to even run with something like a h/e 5 speed mustang ... let alone its more powerful brother ... a 305 or 350 tpi? I saw an article somewhere. I think it was car craft.They built a 305 tbi . Got it into the 11's... yeah it changed my mind about the 305 some... Until they gave their estiamte for how much it cost em. It is after all your choice. Honestly never been a fan of the 305. Not even the tpi. Although I would take a tpi over a tbi.I did have a chance to buy a 92 rs 305 with a 5 speed. But something didnt feel right about the guy selling it. I had the feeling it would go to shit if I bought it so I didnt. Just my 2 :2cents:

I don't bad mouth them, but you hit the nail on the head yourself. "small bore" They have 17% less volume, but their performance potential is alot less than just 17% less. The small bores shroud valves big time. They can make some torque, but there was a reason they didn't ever rev. THey are just as reliable if not more, but if I were to bad mouth them its because they are a poor choice for performance. Its not just parts, either, its the physical limitation presented with the small bores.

I've owned two; one in a light 3/4 truck and one in a Monte Carlo. Both sucked big time. I'm sure they would have lasted forever. One was rated at 145 and the other at 160. Neither made close to that much power... more like 120-140 maybe, but the money I would have spent on getting them to 300 hp would have bought and installed a 450-hp 350 crate motor.

You are correct, though. They get a bad rap because GM never developed good parts for them and now nobody wants them. There is no reason why they cant breathe, its just tougher with the small bores. For my money, why try if I can do it with a 350 alot easier. Its just a game of numbers. I do disagree with you on one thing, though. I think its more expensive with a 305. That shows up in the aftermarket section. More people choose the 350 because its cheaper to make power.

:2cents:

I know a big following for the Olds 307, too. They're big weakness is the windowed main webs that keep them below 7000 rpms.

When I say they are cheaper to build, I meant that the same parts are a bit cheaper for the 305. Take for example the World Products S/R Torquer heads, The 305 torquer heads are almost 100 bucks cheaper for the pair than the pair for the 302, 327, 350, and 400 Small Blocks. Of course the parts that the 350 shares with the 305, like the cam, intake, rods, and crankshaft, they are all going to be the same price of course. I meant to say that they are cheaper to build but what I didnt express is that they are not cheaper to build to get the same amount of power as a 350 for the same price. Of course you would take a big cut in power but if you have the 305, then you might as well give it a shot. You might be surprised that 300 horse is a very reasonable amount to get out of a 305 if you take the time to build it. And hey, I am sure it is cheaper to get the 300 out of the 305 than it is to buy a crate 350 with the same power. You might take a cut in torque but I imagine it wouldn't be loads of it. I would rather go for the value myself but if you are all about loads of power, then the 350 is no doubt the better choice. I would rather be a little different though. And hey, I can always turn to the nitrous for a thrill here and there.

I would rather be a little different though. And hey, I can always turn to the nitrous for a thrill here and there.

Amen on the being different part. I have a 66 Bonneville with a Caddy 500, and I had an 87 cutlass that I was going to put a 302 windsor Ford in it. I knew a guy who put a Hemi in an El Camino.

Amen on the being different part. I have a 66 Bonneville with a Caddy 500, and I had an 87 cutlass that I was going to put a 302 windsor Ford in it. I knew a guy who put a Hemi in an El Camino.
That should be illegal a 302 ford in a GM

The 305 is a great dependable engine and with a little work is a good torqer. I just built a 305 with flat top pistons, LT1 cam, ported and polished heads and exhaust manifolds with over sized valves with a three angle grinde. Added a MSD coil and ignition. Took it down to a dyno test and it was putting out 240 hp @ 5300 rpm. It will smoke the rear tires from a dead stop and get a squeal on the first shift. The autotrans is still stock. So there is a lot of life in the sb 305 with an investment of less than $1,000.
Countilaw :smokin:

True that you might end up with some less power than a 350 by building up a 305, but nobody takes into consideration the cost of having to BUY a 350 to start with. Also, a lot of the 305 parts WILL interchange if ever you were able to step up to a 350. i.e. headers, ignition, some cams, intake, etc. If you have the ability, 305s take very kindly to mild superchargers or turbos. Personally Im starting to think that the Smaller Block Chevy is just a wolf in sheeps clothes.

This is exactly what I was lookin for.......all the things that were mentioned as far as mods go, are any of those made smog legal?....Livin in CALI its a must, because I would love to see what the 305 in my Caprice could do.....unless it gets sold before then

oh yea...and whats the difference between TPI and TBI?...and which is better?

350s were introduced in 1967, when horespower output was peaking. In 1970, when the 327 was discontinued, the 350 that replaced it was putting out 1+hp/cube. 305s were introduced in 1976 when power output was near the bottom of its downward spiral Chevy was putting the worst cylinder heads they ever cast on all small-blocks. Remember the 882 and 624 heads for the 350/400? Burn a valve and throw them away! Good thing there were so many of them! 305 heads were even worse. Between lean fuel mixtures, retarded timing, small valves, combustion chambers so hot that they detonated all the time no matter what you did, the 305 earned a terrible performance reputation. Like the 307, most people don't bother doing anything with them - they just swap in a 350. But performance is on the upswing nowadays, and the 305 has enjoyed the benefits of that too - Vortec cylinder heads, fuel injection, etc. A TBI 305 in a late '80s Chevy truck had the same horsepower rating as a mid ' 70s 350 4bbl. True, you can do everything to a 350 that you can do to a 305 and make even more power, but if you have a healthy 305 that you want to keep, you can make plenty of power with it. F-bodies with 305s run 13s without too much difficulty. And think of the satisfaction of blowing the doors off some idiot telling you what a dog your 305 is!

This is exactly what I was lookin for.......all the things that were mentioned as far as mods go, are any of those made smog legal?....Livin in CALI its a must, because I would love to see what the 305 in my Caprice could do.....unless it gets sold before then

oh yea...and whats the difference between TPI and TBI?...and which is better?

Throttle Port Injection (TPI), Throttle Body Injection (TBI). Supposedly TPI is better.

350s were introduced in 1967, when horespower output was peaking. In 1970, when the 327 was discontinued, the 350 that replaced it was putting out 1+hp/cube. 305s were introduced in 1976 when power output was near the bottom of its downward spiral Chevy was putting the worst cylinder heads they ever cast on all small-blocks. Remember the 882 and 624 heads for the 350/400? Burn a valve and throw them away! Good thing there were so many of them! 305 heads were even worse. Between lean fuel mixtures, retarded timing, small valves, combustion chambers so hot that they detonated all the time no matter what you did, the 305 earned a terrible performance reputation. Like the 307, most people don't bother doing anything with them - they just swap in a 350. But performance is on the upswing nowadays, and the 305 has enjoyed the benefits of that too - Vortec cylinder heads, fuel injection, etc. A TBI 305 in a late '80s Chevy truck had the same horsepower rating as a mid ' 70s 350 4bbl. True, you can do everything to a 350 that you can do to a 305 and make even more power, but if you have a healthy 305 that you want to keep, you can make plenty of power with it. F-bodies with 305s run 13s without too much difficulty. And think of the satisfaction of blowing the doors off some idiot telling you what a dog your 305 is!

Ahhh, the 307 :)...fond memories. Always threw those motors away...shouldn't have though. A 283 bore, with a 327 stroke...the performance possibilities. By the way, 283 (3.875 bore) heads (I'm sure someone has a bunch of them laying around) will fit perfect on a 305 (3.75 bore). Using 283 heads should help the 305's performance without the cost of new heads. Just a little suggestion for the "financially challenged". :)

Beating a Rustang with a 305...priceleless!

Thanks for the bit of info...I never really appreciated the engine until now, owning this '87 LS...I wish I could put a newer 5.7 out the 9C1 in my baby.....and put SS instead of LS in the window. DAMN!!

I have an 86 camaro with a 305. I had a 82 camaro with a 305 and a 350. It got stollen after i put the 350 in it. My 305 was faster except for on take off. The camaro i have now has 3.23 gear ratio, possi rear end, 700r4 trans with a shift kit, a 2300 stall and a stock 305 h motor. 2.0 60 foot time and an et of 9.48 at 76mph. 8th mile. I have out ran numours 350's with both of my 305's on bottom end and top end. you just got to know how to tweek them. one of the motor adjust ments i made was a little bigger carb and advanced the timming and that made a big big difference in how the car ran.

you are sadly mistaken if you think it is cheaper to build up a 305 in fact it is more expensive because parts arent as widely made and sold for the 305.
and it isnt just the bore that is different the heads are different and the 305 blocks arent as strong.
but whatever you say buddy.

I have to take issue with a few things here. First of all, since the 350 is bigger than the 305, it will make more power. The 305 will only outrun a 350 if it is built and tuned better. Also, if the 350 breaks the tires loose and the 305 doesn't, the 305 has the advantage on takeoff. If you replace a 305 with a 350 and put the 305 intake and exhaust on it, it won't be able to breathe and won't make much more power than the 305 did.

I also don't believe 305s cost more to build than 350s. For one thing, cores are cheaper since most would rather have a 350. Jeg's sells World Torquer S/R heads for 305s for about $10 LESS than for 350/400 heads. It's not a big difference, but blows away the theory that it costs more to build a 305. When you consider how many crappy 350 heads there are out there (882/624 castings) that are basically disposable, it makes sense most of the time to get a set of these heads anyway. 305s and 350s used the same cranks and rods, so the only difference is the pistons. The difference in price for a set of flat topped pistons is slight between the 305 and 350. Forget about finding a set of 12.5:1 pistons for your 305, but I'm talking street motors here. Add to the fact that there are plenty of healthy 305 bottom ends out there already in cars people drive every day that just need to breathe a little better to make power, and you have some very good reasons to pump up your 305 a bit instead of going through the trouble and expense of building a 350. Sure, if you already have a 350 to build, go for it! I did, back before aftermarket iron was readily available and the 350 had good factory heads (1971). But there's no reason to give up on your 305. It can make power too. 13-second ETs aren't uncommon for built 305s in 3rd gen F-bodies.

I'll grant you that 305s don't have the beefy main webs that big bore smallblocks have. Ultimately, that will limit the power they can produce. But this will probably never be a factor in a street engine. If you're concerned about how strong your 305's bottom end is, you're probably going to build something bigger anyway. I'll qualify my statements here by saying that pumping up your 305 for the street makes sense, but building a race 305, in most cases, doesn't. That doesn't mean 305 blocks are weak. In fact, they have thicker, not thinner, cylinder walls than 350s. 350 walls are thin in between the cylinders, and are more likely to be unusable due to core shift than 305s. As GM's quality control has gone down the toilet over the past 2 decades in favor of corporate profits (or reduced losses thanks to a weak economy and consumers getting sick of buying junk), this has become more and more of a problem. Engines that never should have made it through the machining process wound up in cars and trucks with head bolts that weren't even tight! I had an '87 Chevy K10 come into the shop where I worked with a blown head gasket and one head bolt halfway tightened but bound up thanks to crooked threads in the block due to core shift. That block should never have made it past the machining process, but profit margins prevailed, the engine was assembled, dropped into the truck on the assembly line, and Chevy rolled the dice, hoping it would make it past the warranty period, Unfortunately, it did. I'm just venting here, but it just goes to show you that while 305 blocks may be weaker on the bottom than 350/400s, they do have a bit more meat where it counts for a street motor.

Dan

305 is a good relieable engine ... i'm going to stroke one to act like a
diesel (crank out of a 400) they can't breath because of the bore &
the available flow. mine is going to work from 800- 3000 RPM's :smokin:

A set of S/R Torquer 305 heads will help it breathe better. If you're putting a 400 crank in it, the motor will need all the flow help it can get! The S/R Torquer 305 heads have 1.94/1.5 valves like basic 350/400 heads. Figure in the cost of new guides, a good 3-angle valve job, and resurfacing on the stock heads, and you will probably find a new set of heads a worthwile investment. If the stock heads need any more than that (like new seats), you might as well throw them away. Recycle them as raw iron for casting a good set of heads!

Dan

who told you guys that 305s have windowed mains? no SBCs have windowed mains (it is too small and too soft to lose critical strength here), and other than variations in the bearing saddle size (pre 68, post 68, 400) the bulkheads are the same. It can be truthfully said that no 305 was ever made with 4 bolt main caps, but then again, a few other bores never have also and its more likely you will bust a rod cap/bolt long before you ever lose a main cap. the stock chevy bottom end will hold 500hp with no changes. 305s on a blower will generally be south of 400hp so it should be no concern

I don't think anyone said anything about "windowed" main webs. That's an Oldsmobile thing. I'll grant you that I'm not sure of the main web thickness on small bore smallblocks and whether or not they can be machined for 4-bolt mains. But I doubt anyone is going to build a 305 that will need them! I believe the advantage of 4-bolt main caps is more rigidity under extreme load conditions. 2-bolt caps concentrate stress on the block at 2 points on each main, right around the journal. 4-bolt caps spread this stress outward.

I did say that 305s have THICKER cylinder walls than 350s, thanks to the smaller bore allowing more meat in between the cylinders. The most unusual smallblock is the 400, which has SIAMESED cylinders (cast together with no space for coolant to run between them and "steam holes" in the block and heads to vent hot coolant trapped where the cylinders run together.

Dan

I will probalby switch out motors whenever the bottom end of my 305 drops out, but until then I would love to find a good intake manifold for my 89 brougham LS. I looked at Edlebrocks Performer TBI, but at the end of the description it says "will not fit Caprice" is it a clearance problem?

If anyone knows where I can track down some performance parts for my sleepy 305 , please let me know.

I think that the only problem with the Edelbrock manifold for the Caprice is Hood Clearance. I could be wrong though, maybe the cowl sticks out too far off the firewall and that could cause problems. Anyways, here is a website that will almost tell all the things that you could do to a 305 to pep it up. http://www.goingfaster.com/spo/modthel03.html

I will probalby switch out motors whenever the bottom end of my 305 drops out, but until then I would love to find a good intake manifold for my 89 brougham LS. I looked at Edlebrocks Performer TBI, but at the end of the description it says "will not fit Caprice" is it a clearance problem?

If anyone knows where I can track down some performance parts for my sleepy 305 , please let me know.

yes hood clearance is a bugger. the performer is I think 3/4-1" taller

I could see the high rise intake creating a clearance problem on a '91-up Caprice, but I have my doubts it will create a problem in your '89. Most of the "boxy" Caprices were carbureted. Only a few years were TBI. This may be why Edelbrock says their intake won't fit the Caprice. You may want to contact Edelbrock to verify this.