Page 1 of 3 123 LastLast
Results 1 to 10 of 26

Thread: 400 SBC Block

  1. #1
    Junior Member SHOW GUEST
    Join Date
    Jul 2008
    Location
    Midland, TX
    Posts
    5

    400 SBC Block

    I snagged a virgin 817 casting 400 block to build a 377 for my dirt modified, but when I talked to the machinist about building it for me, he pretty much said he'd rather not build anything using a stock 400 block.

    I know compared to a 350 4 bolt main block (which loses the big bore benefit), bowtie block or Little M, the stock 400 is the weakest of the bunch. However, I figured at no more than 550hp and 7500 rpm with a short stroke, long rod, lightweight flat top rotating assembly in a 2500lb car would live for some time. This guy didn't want to touch a build like this PERIOD even with splayed main caps.

    What are everyones opinions about using a stock 400 block with stock caps for this application? How long would it live? Will it live at all? What would safe power and rpm limits be before having to really worry about catastrophic block failure.

    Thanks Guys,
    Darren

  2. #2
    Senior Member MASTER BUILDER
    Join Date
    Oct 2003
    Posts
    144
    I heard with 4 main bolt modification, they can be pretty reliable, My 400 bock was a 2 bolt with stud girdle that lived at 7500 rpm for 3 yrs. and produced a bit more than 600 hp.

  3. #3
    Senior Member EXPERT BUILDER
    Join Date
    Nov 2003
    Location
    NORTHEAST
    Posts
    290
    Quote Originally Posted by altune
    I heard with 4 main bolt modification, they can be pretty reliable, My 400 bock was a 2 bolt with stud girdle that lived at 7500 rpm for 3 yrs. and produced a bit more than 600 hp.
    Drag or circle track!!!!!!!!!
    WWW.CNCBLOCKSNE.COM
    IS A DIVISION OF
    HINKSON AUTOMOTIVE
    RESEARCH & DEVELOPMENT

    CARL HINKSON 207-892-7215
    EMAIL [email protected]

  4. #4
    Senior Member EXPERT BUILDER
    Join Date
    Nov 2003
    Location
    NORTHEAST
    Posts
    290

    Re: 400 SBC Block

    Quote Originally Posted by modracer64
    I snagged a virgin 817 casting 400 block to build a 377 for my dirt modified, but when I talked to the machinist about building it for me, he pretty much said he'd rather not build anything using a stock 400 block.

    I know compared to a 350 4 bolt main block (which loses the big bore benefit), bowtie block or Little M, the stock 400 is the weakest of the bunch. However, I figured at no more than 550hp and 7500 rpm with a short stroke, long rod, lightweight flat top rotating assembly in a 2500lb car would live for some time. This guy didn't want to touch a build like this PERIOD even with splayed main caps.

    What are everyones opinions about using a stock 400 block with stock caps for this application? How long would it live? Will it live at all? What would safe power and rpm limits be before having to really worry about catastrophic block failure.

    Thanks Guys,
    Darren
    Over the years we have prepared a lot of 400 blocks and afeter a season of running oly to find a cracks in the decks near the head bolt holes and we have seen cracks in the webbing from the cam tunnel down to the mains. And they are so far out o blue print compared to a good block its not funny.

    Dart has the new SHP blocks that can be bored to 4.165 and I beleive we can machine one out, Line honed, decked, blue print bore and plate hone, clearance the lifter bores clean and ship in the U.S. for around 1795.00

    We have 4 on order just waiting for them to arrive.
    WWW.CNCBLOCKSNE.COM
    IS A DIVISION OF
    HINKSON AUTOMOTIVE
    RESEARCH & DEVELOPMENT

    CARL HINKSON 207-892-7215
    EMAIL [email protected]

  5. #5
    Senior Member EXPERT BUILDER
    Join Date
    Aug 2005
    Location
    Tell City, IN
    Posts
    356
    I had a 379ci destroked 400 and ran it for about 3 years until it finally blew up from too tight mains. I have a 422 now using a stock block with Eagle Billet Splayed Caps shift has ranged from 6500-7000 so far without any issue's. The biggest issue I have read and heard is weak cylinder walls. I added just a small amount of hard blok to mine to the bottom of the freeze plugs maybe a little lower. It never gets over 190 even on 90+ degree race days. I think going with a short stroke helps it live too.

  6. #6
    Member JUNIOR BUILDER
    Join Date
    Jul 2003
    Location
    U.S.A.
    Posts
    80
    I had a good conversation with a respsected engine builder about using a production 400 SBC w/ a 3.375 stroke for a LSR ( Land Speed Racing ) project and he was 100 % against it !!

    He said to use an aftermartket block or forget it ............... ln .02

  7. #7
    Junior Member SHOW GUEST
    Join Date
    Jul 2008
    Location
    Midland, TX
    Posts
    5
    If not for IMCA production block rules, it would be a no brainer to go with an after market block. Unfortunately, that rule prohibits any aftermarket block including bowtie blocks.

    From what I'm hearing I can build a 400 production block based 377, but shouldn't expect more than a couple of seasons out of it at most. That sux!

    Guess I need to hunt down a good 4 bolt main 350 block and build a good SOLID 383. Anyone have one available?

    Thanks for all the replies folks
    D

  8. #8
    Senior Member EXPERT BUILDER
    Join Date
    Nov 2003
    Location
    NORTHEAST
    Posts
    290
    Quote Originally Posted by modracer64
    If not for IMCA production block rules, it would be a no brainer to go with an after market block. Unfortunately, that rule prohibits any aftermarket block including bowtie blocks.

    From what I'm hearing I can build a 400 production block based 377, but shouldn't expect more than a couple of seasons out of it at most. That sux!

    Guess I need to hunt down a good 4 bolt main 350 block and build a good SOLID 383. Anyone have one available?

    Thanks for all the replies folks
    D
    We have had a lot of calls over the years from some of the IMCA guys who have blown up 400 blocks looking for more its kind of a shyty rule as it should not allow a 400 block as it would save the guys some money in the long run.
    WWW.CNCBLOCKSNE.COM
    IS A DIVISION OF
    HINKSON AUTOMOTIVE
    RESEARCH & DEVELOPMENT

    CARL HINKSON 207-892-7215
    EMAIL [email protected]

  9. #9
    Junior Member SHOW GUEST
    Join Date
    Jul 2008
    Location
    Midland, TX
    Posts
    5
    WOW! was that the understatement of the year LOL.

    I do see why they don't allow the aftermarket block though and its because they want to keep guys from building the big motors, thus, forcing the guys who can't afford 2-3 motors per season to use 350 blocks and those who can afford several motors per season to use the weakest SBC block made. I guess their view is if your dumb enough to spend the money to build a big motor with a stock block, shame on you.

    If they would just put a displacement rule in, say 410ci or so, then I don't see any reason for the stock block rule AND everyone would have bigger faster longer lasting motors.

    JMO

  10. #10
    Senior Member RACING JUNKIE
    Join Date
    Sep 2007
    Posts
    4,143
    Just a question....Didn't the sprint car guys used to use the factory blocks years ago? I know they are weak but when I was a kid the sprint cars were running 406 -410 ci and I know the top teams had aftermarket blocks but I mean the more local type racers that still ran well. I am speaking of early to mid 80's. Like I said just asking cause I know there are several options NOW for an affordable aftermarket block but what was around back then?


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Copyright © 2005-2016 RacingJunk.com All Rights Reserved.

Designated trademarks and brands are the property of their respective owners. Use of this Web site constitutes acceptance of the RacingJunk.com
Terms of Use, Classifieds Disclaimer, Privacy Policy, and Cookie Policy