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Old 03-26-2011, 02:56 PM
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305 to 350?

Ok, so I'm a new member to this website, but i've been reading your forums for some time now. One topic that has always intrigued me is the old 305-334 Stroker motor. I'm very interested in this project and plan on doing it to my 92 camaro RS.........However, today's question is this.... from what i know about engines, and from what i gather from the forum is that a 305 and a 350 are exactly the same engine blocks, with the exception of the bore sizes and smaller heads, the blocks are the same size. So when people mention boring out a 305 to a 334, or just buying a 350 and boring it out to 383, why cant you just bore out the 305 to the 350 bore size or 383?

More simply, If the blocks are the same, then there should be the appropriate amount of space between the cylinders to go more than a .030 bore due to a 305 being the same black just smaller bore to begin with. So why cant a 305 be bored out more than .060 over to create a 350 or 383?

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Old 03-26-2011, 03:12 PM
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most of the cubes you mention gaining: 305 to 334 and 350 to 383 do not come from overboring (about 5 of them do). The rest come from a stroker crank (3.75 inches) borrowed from a 400 with turned down journals (you can also buy them premade nowadays).

The reason you can't usually go much more than .040-.060 over is you start running into water jackets. You could never bore a 305 to a 4 inch bore you'd be looking at swiss cheese when you were finished.

K
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Old 03-26-2011, 03:14 PM
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i think the blocks are only the same in external dimensions and the 305 has a small bore and thin walls cast in and the 350 has 4in bore with the same wall thickness.

so what im getting at is the 305 is a whole different block and wont take any substantial boring say 40 tho.

the strokers yo have heard of are most likly destroked 350s.

just speaking off the top of my head there is alot more knowledgeable ppl and info on this topic just my 2 cents
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Old 03-26-2011, 03:20 PM
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I guess that makes sense, i wasnt considering the water jakets and im sure piston sleeves however im still looking forward to the 334 kit

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Old 03-26-2011, 09:14 PM
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Why not just get a 350? All else being the same, it's definitely going to be cheaper and it'll make more power.
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Old 03-27-2011, 12:55 PM
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well, here's the dilema......Yes, a 350 can produce more power than a 305, i got it, but it seems many people dont include several factors when it comes to the equation and calculation of the cost it would take to swap a 305 for a 350.... (1) If you dont have the 350 block, you gotta buy it. (2) If your in a situation like mine, where you dont have your own garage or major motor changing tools, ie...engine hoist, torque wrenches, and overall place to do it, then you have to pay someone to take the 305 out.( and still pay for them to swap out the parts and do the boring on your beefed up 350. (3) once, the 305 is out, you also have to pay for them to put it in and oh by the way, most likely you'll have to buy a new ECM and "brain" because it's just not gonna read or run right plugging it in.

All these extra cost incurred mainly garage and labor with the addition of a block youd have to buy, are still more expensive then just beefing up the original 305 that was in it. and still getting streetable power.
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Old 03-27-2011, 01:19 PM
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The engine's still going to have to come out, machine work is still going to have to happen and the ECM is still going to need to be reprogrammed if you built a 334 too. You've still got a motor smaller than a 350. There's only a handful of decent 305 heads, you're limited on valve size and you'll always be playing catch up to a larger motor.

I like the 305, I own two cars with them, but if I had planned to put money in my vehicle, I would just go with a 350.
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Old 03-27-2011, 08:17 PM
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A domestic 90 deg V 8 cylinder with a 3.48 stroke can make worthy power. The stroke is good , the intake port flow is poor. Newer heads fix this, and can make a large difference after the inital launching crank throws. A stroker kit is going to respond as expected.

They are not good for high performance or heavy vehicles. If shifting 4600-5200rpm and 250-300 hp/Trq is your game, these economical 305's are a charmer.

The hardest pulling small engines are the small bore 5.4L 's Ford's in the van fleet work vehicles. They have a 3.5" bore and 4.10" stroke , and pull a loaded van really well. All stroke , all the time.
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Old 03-27-2011, 08:27 PM
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Quote:
Originally Posted by kar-Enthusiast92
(1) If you dont have the 350 block, you gotta buy it. (2) If your in a situation like mine, where you dont have your own garage or major motor changing tools, ie...engine hoist, torque wrenches, and overall place to do it, then you have to pay someone to take the 305 out.( and still pay for them to swap out the parts and do the boring on your beefed up 350.
(1) 350s are dirt cheap. You can find them in junk yards, on craigslist, heck I even saw one laying in the middle of the street once. Believe it or not, it fell out of the back of a pickup going up a hill.

(2) Are you planning on gutting your 305 then boring the cylinders and swapping cranks with the block still in the vehicle? If not, then Valkyrie pretty well summed everything else up.
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Old 03-28-2011, 07:38 AM
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With a 350, you can build it at your leisure then pull the 305 and install the 350 in a weekend. With the 305, you'll be out of the car for a while waiting for machining, parts, computer programming... A week without the car ( at least) for a small power increase or a couple of days for a large power increase, with the difference in price equaling the cost of a 350 core.
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Old 03-29-2011, 09:33 AM
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305 heads question

I'm wondering if I can use 305 heads (58cc) with the mildest comp thumpr cam for sbc. I'm trying to get a little more compression (pistons are flat top 9.35:1 w/ 64cc heads), however I'm concerned about flow and I read 305 heads don't flow well. Will those heads work with this cam? I know I'm gonna get the biz about buying a thumpr cam, come at me. I bought it a long time ago, plus I live in the city. There isn't a speed limit sign over 45 anywhere and I don't race! I'm thinking 305 heads because they are a dime a dozen, whereas a good set of 64cc heads is a little out of my price range.
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Old 03-29-2011, 03:35 PM
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Quote:
Originally Posted by Bad66
I'm wondering if I can use 305 heads (58cc) with the mildest comp thumpr cam for sbc. I'm trying to get a little more compression (pistons are flat top 9.35:1 w/ 64cc heads), however I'm concerned about flow and I read 305 heads don't flow well. Will those heads work with this cam? I know I'm gonna get the biz about buying a thumpr cam, come at me. I bought it a long time ago, plus I live in the city. There isn't a speed limit sign over 45 anywhere and I don't race! I'm thinking 305 heads because they are a dime a dozen, whereas a good set of 64cc heads is a little out of my price range.
Some 305 heads are better than others. If you want to make any real power, you want the #4416 castings. In stock as cast form the flow and power is modest.

But if you fully port these 305HO heads with larger 1.94x 1.60 valves these heads work very well. 400hp capable with a good honest port job and the larger valves. A simple quick "pocket port" job is not what I'm talking about. You need to open them up to flow by getting serious with the die grinder.

The thumpr cam needs gears + a high stall and a modified distributor curve
and high compression ratio is your friend.
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