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  #1  
Old 02-16-2011, 04:43 PM
turbotim23 turbotim23 is offline
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Default What is the maxium horse power a 383 block can take and last?

Hi I'm building a blown, injected, intercooled big block. I plan to use a rebuilt 383 block I have to start with. This 383 block will give me some experence programing the electronic injection and if I make a mistake tunning it, it won't be quite as bad as if I did it to a better motor. This 383 is a good quality rebuild that has many improvements. Has a forged stock crank and rebuilt stock forged rods[ I might replace these with better forged ones yet] with the forged TRW pistons,It has eldebrock alum heads,and I'm thinking of using a main cap support to support the bottom end better. It's a 9:5:1 motor but pistons don't come up all the way, they sit .020 down in bore at tdc.Plus I have .100 copper head spacers,[have adjustable length pushrods to make up this difference] . Between being .020 down in the hole and the head spacers I hope the compression will be close to 8:1 and good with boost . With this setup I can set boost and horse power levels at what ever I want. the question is how high do I make it? I've been told by some I should just run 2-4 lbs of boost and just go for looks no big amount of horse power. I don't want to do that ,I would like to have as much power as I can and still have the motor hold together. What horse power level would you feel safe taking this motor too? Thanks for your help
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Old 02-16-2011, 08:39 PM
Rich Kinsley Rich Kinsley is offline
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Sounds like a fun project! I don't think I can be of great help with your question but I don't think I'd worry until I thought it was up around 500hp. I think those 383's are pretty stout.
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Old 02-17-2011, 12:32 AM
cudabob496 cudabob496 is offline
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Not sure, but 440 block may be stronger.
My guess 500 to 600 horse, but make sure the block has no cracks.
Pistons in hole like that may make you more susceptible to detonation. Maybe a zero deck height with more cylinder head volume would be better.
Odds are if something was gonna blowup, it would be caused by other component failures, before the block goes!
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  #4  
Old 02-17-2011, 08:37 AM
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JVMopar JVMopar is offline
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The low deck blocks are stonger than the raised deck blocks. And the later blocks are stronger than early blocks.

http://www.440source.com/blockinfo.htm
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Old 02-17-2011, 01:05 PM
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Slingshot383 Slingshot383 is offline
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You will get some cap walk in high HP numbers, and if you really push it, it can break a main cap. My 400 was running high 7's, and 2 mains had some fair signs of cap walk.
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Old 02-17-2011, 02:23 PM
rampage_82 rampage_82 is offline
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Well as far as I can tell with the deck height you stated and the .100 head gaskets you should have a compression ratio at about 7.8:1. As far as the parts you have, I would say that the bigger issue would be the stock rods rather than the block. Now Mopar has about the best stock rods in the industry, however the failures are usually in the rod bolts themselves only being 3/8's, that would be the major upgrade that I would recommend. The block itself with a girdle should be good to 650 to 700 hp (assuming that you use some block filler) I don't know who told you to limit the boost to 3 or 4 lbs, I wouldn't be afraid of 10 with head studs, and a good MLS gasket, much less a copper gasket which has been "O" ringed. A 383 block is not quite as stout around the crank as the 400's, however they are stouter than a 440, and the cylinder walls are shorter "more rigid" which helps some too. Hope this helps....
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Old 02-17-2011, 02:27 PM
rampage_82 rampage_82 is offline
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BTW the big block Mopar is a great foundation for forced induction, the bottom end is wicked stout, plus there is a ring of 5 head bolts surrounding every cylinder very nice design... Think of that next time you look at a 460 furd, it will make you smile...
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Old 02-17-2011, 06:22 PM
turbotim23 turbotim23 is offline
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Yes I thought I should replace the rods and rod bolts and I've checked into a girdle. I think you have to alignhone the mains with girdle on though,I believe you can't just bolt one on and my motor is done already.I have a new set of main studs that I could use if I do go to a girdle. I already bought 55lb injectors for this project. I'm running the accel efi system and it has a adjustable impedance box for the injectors so I think I could dial the injectors down to apx. the 500 hp level if I wanted, they are good for apx. 660 horse power normally or as much as 900 if you raise the fuel pressure higher than normal. I do have to check with accel about how well some of this will work long term though. A 7:8:1 compression ratio would be just fine. A little less compression might be better as I'm not going to have a good quench zone like a normal blower motor would. Thanks Tim
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Old 02-17-2011, 07:40 PM
rampage_82 rampage_82 is offline
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Yes you do have to align bore the block for the main studs, now if I were to do a girdle (which I am on my 440), I would just get a complete kit such as hughes or 440source, which comes with all of the spacers, bolts, and main studs. I believe that will be a serious time saver. Plus it isn't a big deal to align bore the block, if you are going to upgrade your rods anyways. The quench isn't going to be a real big problem if you are going to have it intercooled. Also you can always go with a snow kit (water-methanol injection = windshield wiper fluid), if you are having detonation trouble. Or play around with E85 that works well too....
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Old 02-18-2011, 03:08 PM
turbotim23 turbotim23 is offline
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well I don't want to put too much into this motor otherwize I'd be better just doing a good motor to begin with,probley a much bigger and better motor also. My plan with this motor is to get it on the road fast this year and get some experence programing it. I might just set it for a little less hp, say around 600 hp. Enough to get some use of the supercharger but not have the motor grenade itself quickly after just a short time either. hopefully if I set it up for that I don't take it up to that level very often or past it and hurt it. Thanks Tim
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Old 02-18-2011, 04:25 PM
rampage_82 rampage_82 is offline
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Well before you knock the forced induction 383 check this out, now granted he has done all of the tricks, but it's still a stock block... http://www.youtube.com/watch?v=QR7iB...eature=related and find more here http://www.moparmusclemagazine.com/e...hallenger.html or http://www.sd-concepts.com/pages/cfVehicleGallery.cfm
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  #12  
Old 02-19-2011, 05:44 PM
turbotim23 turbotim23 is offline
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Yes I seen that car years ago in I think Mopar muscle. That car is a great sleeper I liked it but I didn't have the money to do something like that. I decided with all the 671 superchargers out there it would be a easier and cheaper to set up that type of system. Ive been buying a part here a part there for years, Looking for used parts and cheaper parts. Took a lot longer than what I thought it would but I'm getting really close now. Not all of the parts are top notch but they'll work. What I have will never be a sleeper. It's a 671 blower with superchiller intercooler under it.On top I'm using a BDS electronic fuel injection plate and fuel rails with a birdcatcher hat and filter. I'm going to be using the accel 6.31 efi system with accel 55lb injectors modified to fit the BDS injection plate. The efi is a older system. They have a lot better systems now but I bought that one years ago and will use it. I'm doing what ever I can to save money including polishing the blower etc so it takes a while but I hope to have it running pretty soon. A lot of my problems with this car is not the engine or blower but that everything else has to be made stronger to handle the power also. anyway thanks for your replies Tim
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  #13  
Old 02-28-2011, 06:44 AM
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toad490 toad490 is offline
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If you want max hp out of a stock block there is three things you must do. First ally main caps, these will eliminate most cap walk. Stage two, add a main cap girdle, cap walk eliminated for the most part. Stage three, a partial block fill, to the top of the frost plugs or bottom of ring travel.

Of course the first thing you do with any block is sonic check it for core shift. If you do all this you should be good for 900-1000hp.
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Old 03-10-2011, 01:12 AM
djswwg djswwg is offline
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milodon makes a really strong set of main caps for the mopar big blocks. part #11360 is the centre 3 caps and will probably be good for 650-700 ponies. part #11365 includes all 5 main caps and will take more punishment than any stock block (or rods/crank) will handle. the weird part is they come with bolts and a strong recommendation to use studs. strange. anyway, ARP studs for the mopar engines are too short, order a set for a 460 ford, they are longer and work perfect. btw, they have to be align bored...........djs
ps. i've used girdles before, but the upgraded caps are far easier to work with, aren't prone to gasket leaks like the girdles do, and leave the oil pan at the same height it was.the girdle lowers the pan it's thickness plus another gasket
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Old 03-10-2011, 07:08 AM
DartGT66 DartGT66 is offline
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The main problem is not the weakness of the stock caps. I used stock caps with studs for several years in a 700+ hp street engine that got beaten a lot. It's the weakness of the block itself, and that's something that stronger caps will not cure. Aluminum caps are soft and take the worst hit out of the block, they have been used very succesfully in high hp applications and practically eliminate the strength proplem. Of course the best and the right solution would be a race block if you are making race hp.
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