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Old 07-24-2007, 09:22 PM
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SB 350 or 383?

I want to build an engine of 400+ horsepower. I am totally new to this. I'm hoping to gather some useful information here. I'm going to start the project with a 350 chevy block with a 4 bolt main. Here is my main question: Should I get a 383 stroker kit off of ebay for like $600 or should I keep the 350 displacement and build it up with heads, pistons, and rods? What would be cheaper in the end? I want this engine to last awhile and I want to use pump gas with it. I also hope to make a few trips to the dragway with the engine. What is an ideal combination for hopefully under $2000? Thanks

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Old 07-24-2007, 09:49 PM
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The more cubes you got the easier it is to make power. If you go with the stroker kit, then get one that`s already clearenced since your a novice. If you still don`t want to push it too far, just build the 350 for starters, building a basic 350 is a breeze and would be a great platform for you to learn your skills on.
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Old 07-24-2007, 10:21 PM
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i'm up for a challenge. What exactly needs to be clearenced? Is it the rods on the cylinder walls? or the crank on the oil pan? or somethin else? Thanks
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Old 07-25-2007, 01:40 AM
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There are 3 clearance areas that come into question with a 383. If you use 5.7" 350 rods, the heads of some of the bolts will get chummy with some of the cam lobes. There are two ways around this. Either do a little grinding on the head bolts to provide a clearance of 0.050" to 0.080" or purchase a cam that is ground on a reduced base circle so the lobes are further away from the rod bolts. With a reduced base circle cam such as this, you will have to use longer pushrods to compensate because you're moving the lobes of the cam further away from the pushrod end of the rocker arms. You should check rocker geometry anyway on any build.

The second area is the big end of the rod at the pan rail at the bottom of the block where the oil pan bolts on. Again, a little grinding on the block will fix it.

Third area is the balance pad on the small end of the rod. Check for clearance between the pad and the underside of the piston crown through a full swivel of the piston on the rod. Find some way to do this before the pistons are pressed onto the rods. I keep a used, reduced diameter wrist pin on the shelf for such checking. I just chucked up an old wrist pin in the lathe and sanded off a couple of thousandths so it will fall together in a pressed-pin rod.

You can side-step all this clearancing if you use 5.565" 400 rods, but then, I wouln't recommend it. Piston choice is much better with the 5.7" rods.

All blocks and rotating assemblies are different motor to motor, so you may have to take off very little or none at all.
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Old 07-25-2007, 08:48 PM
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okay, this is some good info. thanks! im going to look for a block this weekend without anything else... just the block. do you know where i can look for something like this? and what would be a fair price for a 350 4bolt chevy that isnt all rusted and stuff? Thanks
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Old 07-26-2007, 01:40 AM
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For a mostly street, a little strip action motor, you won't need a 4-bolt block. A 2-bolt block will work nicely. I just checked craigslist here in Phoenix and found a 0.030"-over 4-bolt block and crank for $50, I think I'll go buy it. Found another 4-bolt in nearby Casa Grande for $100.

Somebody in Methuen has a long block and intake for $100

Cape Cod.. 86 4-bolt short block 48000 mi.$300.00
Wouldn't this be a roller motor w/1-piece seal?

Last edited by techinspector1; 07-26-2007 at 01:50 AM.
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Old 07-26-2007, 07:24 AM
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Quote:
Originally Posted by techinspector1
Cape Cod.. 86 4-bolt short block 48000 mi.$300.00
Wouldn't this be a roller motor w/1-piece seal?

Edit: just re checked on that, yes I think 86 is the first year for the 1 piece-

K
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Old 07-26-2007, 08:38 AM
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The ever eternal question. 350 or 383. This past few years I have been building a 79 camaro redlight racer. I bought new crank rods pistons the works. But I bought a 350 crank, and stock pistons. I also bought 1.5 roller rockers and the cam that I wanted. It has double hump heads and a 750 holley on top. This motor will make somewhere in the neiborhood of 360-380 horsepower (at the flywheel). Now the question why didnt I buy a 383 crank, well because a 350 will spin up much faster than a 383. Which is what I was looking for on the street.

Just because you are new to this, doesnt mean that you cant do it. If you want a 383 jump in and do it (feet first!). you'll run into more problems along the way but take your time and do it right and you'll have a motor you love (and are proud of because you built). Thats the way I learned and I'v built 4 motors that are daily drivers, and are still together.

If you plan on a 383 run down to the craft store and get some clay....lots and lots of clay......

Holder350
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Old 07-26-2007, 05:13 PM
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So youre saying you built up a 350 for your camaro? If I were to do what you did with that motor, what would the total bill be? And if you have stock pistons and crank, why do you have so much power? do you have longer rods for more compression? smaller combustion chambers? Thanks again. I have no problem with just building a 350 but I never found a good enough explanation of which parts to use and what to machine to build a 350 making near 400 horses. There's one more question. I've found this ad-> here . I would go for that, but It seems like a big deal to redo that engine because it's all rusted. When you guys find used blocks, do they look like this? How can I clean that up and make it paintable/machinable? I'm pretty sure thats a good deal, right? and whats the difference between a 2 peace crank seal and a one piece? which should i get? and is there a difference between a 2 and 1 piece seal on the block? or just the crank?

Last edited by awoodman; 07-26-2007 at 06:46 PM.
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Old 07-26-2007, 08:46 PM
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Small block Chevys leaked oil from the 2-piece rear main seals for 30 years ('55 to '85) and the early blocks are still being rebuilt by rodders and others and they still leak, even today. In '86, Chevy went to a 1-piece seal so that there is no gap on each side of the seal to leak. I'm pretty sure they went to the roller cam the same year, so that's why I included the '86 motor that I showed you in Cape Cod on my other post. If I were you, I'd burn rubber gettin' over there and rip the stitches out of my back pocket gettin' to my wallet.

If you're going to build a reliable motor, I strongly suggest using a hydraulic roller cam. Retro-fitting a roller to a '85 and earlier block is a fairly expensive proposition, but the '86 is already engineered for it, so with a 48,000 mile motor like the one in Cape Cod, all you'd have to do is change the cam to the one which matches your static compression ratio and re-use the factory roller lifters.

You can build a very nice 350 that will do what you want it to do, although I wouldn't necessarily focus on top end horsepower, but rather on maximum torque at the lowest possible rpm's for a street motor. Speaking generally, a 383 will make more torque than a 350 with basically the same combination of parts used due to the additional leverage on the crank provided by the longer lever arm of the 3.75" crank as opposed to the 3.48" stroke of the 350, just like you can apply more torque to a bolt with a longer wrench using the same physical effort.


By the way, longer rods, or shorter rods, in and of themselves, do not contribute to a higher or lower static compression ratio. You change that by using a longer or shorter stroke crankshaft, different piston crown configuration, different piston deck height, different gasket thickness or different volume in the combustion chamber.

Take a look through these dyno-proven engine combinations. They were compiled from magazine articles by some guy named Ryan and have been a source of intertainment for me for several years now. There are a total of 109 combinations from which to choose and most all of them are using streetable static compression ratios for use with pump gas. Look for the ones that are making at least 400 ft/lbs of torque at under 4,000 rpm's. Those will be the stump puller motors that will make a nice street combo. If you don't know what some of the specs are, just ask. Everyone on this board is knowledgable and willing to donate their time and expertise to help those who need a hand.
http://www.ryanscarpage.50megs.com/combos1.html
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Old 07-26-2007, 09:26 PM
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350 or 383?

I'm going to disagree with Holder350 and his "350 spins up faster than a 383" comment. I've heard this same load of BS-old wive's tale so many times it's getting to where it makes my head explode every time I hear it! If this were true we would all be looking for the smallest cube V-8's we could find so that we could blow the doors off of every big block we ran against! Pro Stock racers would be sleeving down 283's to about 190 cubes and blowing off everyone in sight and setting new E.T. records!
Here's why this is BS-How fast a motor free revs when in nuetral is meaningless, it's how fast it can rev against a load that matters, and to accelerate against a load faster means you need to make more torque or pull a lighter load.
You will never see a competitive racer pull a bigger motor and replace it with a smaller one because revving quicker will make him faster- because he knows better! I should probably realize you're only 19 and haven't learned this yet
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Old 07-26-2007, 10:39 PM
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AMEN Ericnova72,

I am not sure if everyone knows what a 383 is in this post. I Rev my 388 roller to 7200 all day long! A built 350 and a built 383 with good comp ratio makes 1.2hp per cube 38 cubes =45.6 more hp over the 350 on rebuild, and generates a ton of torque. Why not build a good 406? Heavy cars like torque.
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Old 07-27-2007, 07:08 AM
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Quote:
Originally Posted by awoodman
So youre saying you built up a 350 for your camaro?
Yes 350ci 79 camaro. Please realize that that is flywheel HP not wheel HP. And the reason that I have so much power is because I carefuly chose the correct cam, intake, heads, and headers. Bigger is not always better......but its a good place to start.

750 holley is modified, edelbrock Airgap intake, nice comp cam (little larger than a LT1), modified heads , roller rockers, and it all runs on pump gas.

Cost - Around 2,500

A 350 can make 500hp if built right. Not that big a deal.....stock you will only make about 1hp per cubic inch but its not a big deal to make over that if you want to spend the $$
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Old 07-27-2007, 07:41 AM
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Quote:
Originally Posted by ericnova72
I'm going to disagree with Holder350 and his "350 spins up faster than a 383" comment.
I'm not saying that a 383 wont beat the doors off of a 350 on a long stretch. Its the same deal that dirt racers here run into stroker motors wont run as fas on a short track because of the fact that it takes to long to spin that long stroke up before you start into the turn. Then go to a long track and a 383 can power down the straights because once it gets to optamal RPM it will make more power.

And as for the small vs big block theory, I was not talking about anything to do with a 200ci jump in motor size. Were were talking about a 4ci difrence per cylender, with the same bore size.
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Old 07-28-2007, 08:11 AM
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So I'll be fine with just a 2 bolt main? I might go to look at this later on today. Is the 158k miles a problem or not, since im rebuilding it?
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