383 sbc build

General engine tech -- Drag Racing to Circle Track

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MadBill
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Re: 383 sbc build

Post by MadBill » Sat Feb 09, 2019 10:38 pm

In some engines the main webs are so thin that
Block.JPG
two extra threaded holes make the assembly weaker... :shock:
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Newold1
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Re: 383 sbc build

Post by Newold1 » Sun Feb 10, 2019 2:02 pm

Four bolt mains versus 2 bolt mains wont necessarily solve block failure issues. The example above of a 4 bolt block cracking at the main cap pad shows that magging a block and sonic testing for thin areas as Blockman reminded should always be done on any donor or replacement block! "Leave no doubt, check it out"! :wink:
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F-BIRD'88
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Re: 383 sbc build

Post by F-BIRD'88 » Sun Feb 10, 2019 2:17 pm

If you build the motor with the correct compression ratio for the fuel used, you won't have trouble with a 2 bolt main block. Detonation is what kills the mains and crank too. If you'll be using crap gas build with less cr.

DSRE388
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Re: 383 sbc build

Post by DSRE388 » Mon Feb 11, 2019 9:54 pm

I have built a few 2 bolt 1 piece rms blocks with studs up to 514hp 502tq at 383-388cid and been lucky i guess!
Street strip deals making peak power around 5800-6100rpm
These were budget engines and i never recommend doing this now especially with Dart SHP blocks being affordable its a much better way to go for just a little more money and if you can't do that you can do a 2 bolt block with splayed center caps for extra strength.
Imho RPM and rotating/reciprocating weight and detonation are what kills most bottom ends and blocks like others have said

mtmvette
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Re: 383 sbc build

Post by mtmvette » Wed Feb 13, 2019 1:48 am

If you want to keep it retro and need a mechanical fuel pump then just use your 2 piece blocks. However, in this day in age, I would not run anything but a roller cam and if you use the "old " block, you would have to get a retro roller kit. Purchasing a '96 - 2001 350 Vortec would get you a roller cam, vortec head, and a one piece seal package. That would be a good start. These engines came in GM trucks and vans. They are cheaper now because of the LS craze. Have the block and heads checked well even if you find a "good running" engine, as the heads are prone to cracking. Run a 5.7 rod Scat rotating asm with desired compression and a nice muti angle valve job, (read articles on setting up vortecs for higher lift cams - most shops got this by now) 260 - 270ish cam and you should have a nice street engine.

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