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283 to 302
ok here's the story and i know you guys are gonna tell me that a 283 is not worth my time and money but it's all i have now. I want info on making this 283 into a 301/302. Here's what i know now 283 block bored .125" over making the bore 4.000". A 327 crank (small journal). I can use the 283 rods. now the question of the day is what size pistons do i need and what size cam should i use? do the pistons have to be special or can i use any 4.00" bore pistons? i understand the block casting has to be a certain # and year, both of which i do not have yet. so any info you can give me would be great thanks.
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Patience young grasshopper. You say the 283 is all you have right now. If you are willing to put money into it to make this way more expensive 302, you obviously could set aside the money to get a 350+ SBC. Sell the 283 to someone that has it stuck in their head that it is cool to build 283s. Let them be different. I called around to the local machine shops. Within a couple days I found my standard bore 400 that was already checked for cracks. I even got a receipt with it. IT cost me $200 for just the block. It was worth every penny. You could find one of them, or look for an '89 350 with the roller cam. That would be much wiser. |
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to make a 302 you need a small journal 283 (3" stroke) crank & a std. bore (4.00") small journal 327 block. not hard stuff to find. i agree with every one else though. i would spend the same money on a 350 383 or 406 first. sense your having to buy every thing any ways. the 302 chevys run about like the 302 5.0 gt mustang fords, weak as hell in factory form (in my opinion), but they came be made screamers. if you want to be different take a 327 crank & put it in a 400 block. you would be much happier.
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I disagree with everyone else, If you want a 302 then fine. To each his own. they're great motors and can handle gobs of RPM, unlike they're big inch counterparts. Everyone is so biased to big inches these days, the days of big gas prices, I don't understand. Like I said though, to each his own. My next motor was gonna be (because I have all the parts kickin') a 383 SB. but I'm kinda thinkin' 'bout a 352 SB (400 with 327crank) or a 302, or another 327, These motors can easily handle the high RPM that make the bigger cube guys cringe, without the high buck forged this and H-beam that. The old saying "there's no replacement for displacement" ya, say that to my wallet at the pumps. Point is.... why tell anyone to get a bigger motor, you can have a small fuel-mizer motor that can just unleash the havoc at 7500rpm and live well with cheap stock parts, if you build her right...
If my tach was bouncin' 7300 everyday, with a 400, I'd be sweatin' But I got a 327, I'm dry as bonneville... and as fast bahahahaha |
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I'd take a 283 any day. They are great motors. The later blocks will generally not take a .125 bore and even the earlier one should be sonic tested as many of them ended up being boilers. I think mid 61 was the transition. A 327 crank in a 283 block makes a 307. We used to run those in a late model sportsman class that had a 320 inch limit. Bored .060 it made a 317 and those engine screamed. We ran 7800 rpm. As mentioned the 61 and earlier blocks won't take the 327 crank without machine work.
I like the small journal cranks. Most were steel and the bearing speeds are much lower. Even bone stock old 283s used to take a whipping and keep on ticking. I remember several that would tach to 9 grand and weren't realyy "built" |
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Now you put a 327 crank in it? Do the math, your going to end up with 326.7cid as Doublevision pointed out. To make a 302 with a 283 block, you need a 4" bore, so your .125 overbore is correct, but you have to keep the 283 crank because the whole point is to have a shorter 3" stroke. If you want a 302, which I am also building I would advise against boring the 283 .125 over for the reasons Willowbilly pointed out. Get yourself a small journal 327, and your 283 crank and you've got yourself a 302. Speed Pro make some good forged 302 pistons and you might want to consider 6" rods. If you want a little bit more displacement bore it .060 over and you have a 310.7 but I wouldn't go much more than that. If you want an idea of likely performance, check out Willys desktop dyno run of my build in this thread. http://www.hotrodders.com/t62564.html Good luck! Rich
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hey guys i really appreciate the help, I guess i was confused on the 3 inch stroke on the 302. this all makes sense now. so what i will do is just rebuild to stock this 283 and put the money to a 350. it's hard to believe that a larger displacement engine is so much cheaper to build on. and i do have a 350 on the way i just dont have anyplace to put it. but thats for a later thread. once again thanks for helping out a newbie. you guys are great.
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I still have much respect for the 327, just look at my picture.
As for the saying "you can`t beat cubic inches" is because you can`t. there has been so many small block versus big block wars in the magazines, both engines of equal cubic inches, while the small block could come close, close isn`t close enough, the big block always prevailed. Also better fuel economy can be had from a larger engine, it all comes down to combustion efficientcey as well as cruise RPM, there are many factors as far as that goes. You also have to take into account that when you rev it you use fuel period, engines rev best with the foot to the floor and this is when the most fuel is being used. When you build a high revver on the street you have to gear it low since it has no low end torque, and this makes it drink gas due to the lower gears and higher cruise RPM, and if you run regular street gears with the ratio in the mid 3`s and you race someone in the 1/8th mile that has a larger small block built for low end torque with the same gears, by the time you get it revved good he`ll be long gone and you`ll never catch him by the finish line. As for a 350 being cheaper to build, it is because it`s the most common, and to show what Luciano was saying is true, I have a 350 block, laying under the back of the house I`ll give to you if you`ll pay the shipping, but this block will need a good clean up as well as bored, so you could likely find a block locally a lot cheaper, Lucky Luciano also gave you a good tip on the roller cam blocks, this is what I`m building now from a 97 Vortec block. |
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I.m not saying they are faster but I would still take a 283 over a 350 anyday
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283 to 301
In the late 60s I had a 301 and 2 292s (60 over 283) With 336 stock rears in them they would rev to 7500 every time all the time. I now have a 350 in a 57 chevy and STILL miss taking it to 7500. 5500 to pushing a 6000 and its done. All this with a solid cam and big springs. No, ther is NOTHING like pulling those Rs, and with todays 5 speeds with the low first gear, they can come out of the hole strong, then sit back at2000 in 5th on the highway. I built 63 or newer 283s because you could buy the whole block in a junkyard for 20.00. I used the 63s because they had power-pack heads on them. When I see every body putting special heads on their street car and never getting the full benifit from them, I sometimes wonder why. Steve
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It hasn't made a lot of difference, the 327 with 11.9:1 comp ratio, .602/.602 282/282 roller cam and six Holley 94's is predicted by Desktop Dyno to peak at 511lbs/ft at 5500rpm and 644hp at 7500rpm. The 302 I was planning was going to be identical apart from a 283 crank, and it was predited to put out 471lbs/ft at 5500rpm and 613hp at 7500rpm, so both torque and power peaked at the same place in the rpm band anyway only I gain 40lbs of torque and 31hp with the extra cubes. I don't really expect 644hp out of this motor but it seems high compression and high revs can bring out the monster in a small displacement small block. Rich |
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