73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 85MudMonster on May 02, 2008, 06:42:50 pm
-
I waas just wondering, aren't the 305 and 350 blocks basically the same just the 305 has a smaller bore? so how much can you bore out a 305? Factory is 3.736, and I wanted to go .130 over to get 327ci, but the don't make pistons for that, so I was wondering if there is actually a difference in the blocks that makes it so you can only bore a 305 .080 over....
I hope all that made sense.
-
Yes ther is a difference in blocks (bore size)
You can make your 305 into a 334 by changing the crank
A .030 overbore with a 3.75" stroke crank = 334 Cu In.
here's some pistons
http://cgi.ebay.com/ebaymotors/KEITH-BLACK-PISTONS-FORGED-SBC-334-DISH-10-00cc-909_W0QQitemZ230218731081QQcmdZViewItem
-
well, I wasn't really looking to change out the crank in it. I just wanted to bore it out as big as a 305 will go, but I don't know how big that is, After it's done it's gonna get put into a '71 Opel GT.
-
got something like this in mind?
(http://www.4x4offroads.com/image-files/1972-opel-gt-264.jpg)
-
that is one crazy lookin opel, where did you ever find that :o
-
Overboring the 305 is a waste of $. For the cash you'll spend on machine shop work just to get .060" max you could pick up a good seasoned 350 block.
-
You'd have to/ take the block to the machine shop and have them check it for bore thickness and such. All blocks are a little different so max bore varies (not much, but a little). The main thing about 305 blocks is that aftermarket heads are harder to find because of the odd bore size (3.736 inches). 327s and 350s share the 4.001 inch bore size and 350s are about as common as trees or grass, so everybody makes heads for them. Otherwise they are the same as far as bolting everything up. making a 327 if you can out of a 305 would give it a boost in power and more economy than a 350, and would be different than everybody else. If you just want to reuse the stock 305 heads, you'll have no problems with anything else you want to add bolting up and fitting. As far as pistons, to get the 327 you need 3.866 bore pistons. With that said, if you cannot find pistons you might look into the pistons for a chevy 283ci (3.875 Bore) or 307ci (3.876 Bore). I'm not sure what all is involved in swapping pistons as far as connecting rod compatibility, or factoring in rod length, etc so be sure it will work before you buy it. Good luck!
Kenny
-
I agree with Vile, unless one is needed to use the "correct" block, as in a stock class of some race rules or for smog rules. The 350 block will cost no more & likely cost less due to being more common. It's good to see someone thinking off the beaten path in our hobby, that's how new things happen. I this case, you can't beat a reliable 350 block. Lorne
-
i thought 305/327/350 blocks were basically the same also. So, what is the difference?
Actually, i thought all SBC's except the 400 were basically the same block.
-
They're all similar in casting but each engine is cast with the intended bore in mind when they are born. They are not the same.
-
No, It's gonna be an expensive build anyway. But I've got the 205 already, so when it is built is will be a 351 SBC, and best estimates from my Engine Dyno Pro software says about 500HP and 550Ft/lbs of torque (but that's a computer program so it's just an estimate not actual numbers) It's gonna get the works done on it, but this will be after I'm done with the 350 and it is put into my truck, I was just wondering what the difference was and how big I could go...Thanks.
-
If your planning to spend big bucks on a build, Why limit yourself to the "I already have it excuse"? Not to be a downer, But how did you come up with 500hp/550ft.lbs out of a bored 305?!!! You had mentioned you were leaving the stock crank, changing it would be the start of getting the torque up, Sorry I just don't see it. Short of a pro-stock type build, you would be lucky to get much over half that! Are you planning on this being a street engine? As stated earlier, the cost is the same (maybe less) with a 350 block. As the saying goes "No misplacement for displacement". Now if you said "I want to spend some bucks & end up with a 500/550 383", I'd think that is very doable. Just my two cents, Lorne
-
Well we'll see. I'm gonna build it and then I'll have to dyno it and we'll find out how good I did. That 305 will work just fine. If I wanted another engine why would I get a 350 anyway, when I could get a 400, or just go crazy and cram a BBC into it.
-
Well we'll see. I'm gonna build it and then I'll have to dyno it and we'll find out how good I did. That 305 will work just fine. If I wanted another engine why would I get a 350 anyway, when I could get a 400, or just go crazy and cram a BBC into it.
Before you dive too deep into the machine-work you'd be smart to get that block sonic tested to see just how much overbore it will take.
The 267s and 305s used different casting cores than the bigger displacement engines, you're probably not going to have enough 'meat' in the cylinder walls to safely punch it out to 351 CI without sleeves :(
Like the others have said, it's *your* money, but you can get a *lot* better bang for your buck with readily available 350 parts 8)
-
305's are great if you own a boat and a thick chain.
-
305's are great if you own a boat and a thick chain.
lol
-
Stop messing with my engine! Just kidding.
Why does everyone like a 283, but hate 305's? The 305 has a 22 inch advantage.
-
The 283 packed some punch for what it was at it's time in life. The 305 was the loaf
-
i argue that the 83-88 monte carlo SS could and did click off mid-15 second 1/4 mile times with a relatively stock 305. The monte carlo, as you know, weighed about 3400-3500 lbs.
This contrasted to the 57 corvette, which was probably the 283's most shinning moment, weighed considerably less and was able to acheive high 14 second times. But, this engine was equipped with the fuel injection system.
If the 305 had such as system installed, who knows?
i don't think a stock, carbed 283 can beat a stock, carbed 305.
Actually, this is getting geeky. i just like 305's.
-
i've officially retracted my post; Arguing wether a 283 or 305 is just too geeky; It's something like what that comic bookstore owner in the Simpsons would do. And that's probably someone who we probably should not nessesarily aspire to be.
i just like 305's and i plan on working with them in the future. If you all want to continue the debate and/or expand upon my argument, that is fine.
-
I personally don't think the 305 is a bad engine. They have served many people many a miles. It's just best left as that, a reliable engine for the average person to get from point A to point B. Many 267's,ect. ran many,many miles in those late '70's early '80's cars, they weren't bad engines, just not a great foundation for a performance build in my opinion.
-
with gas heading to $5 a gallon I'd like to find an old 267 to play with.....
I do have a L99 crank, I guess I could make a 267 with a 305 block if I could find some factory 5.94" rods
or a 302 (306 @ +.030) with a 350 block
-
305's are great if you own a boat and a thick chain.
Or if you are running mud and need throw away motors. $100 bucks in bearings and stuff and you can pull two or three times and then do it over again and not feel bad about it. Or you can pull the crank and rods since many 305's have X-rods... not a major performance thing, but a little better than the bone stock ones. Cranks are the same too if you have to build a 350 on a really tight budget.