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    Results 21 to 33 of 33
    1. #21
      Join Date
      Jan 2022
      Posts
      25
      Thanks for the advice guys I only autocross this thing 10 times a year tops and what about a lsx 427 but I think I would still have to swap exhaust out.I auto cross with a fast bunch of guys and 2 of them have small block chevys and there about the fastest out there a ls would be nice but I would have to scrap all the stuff I all ready did for the car like a complete march serpentine pulley set up and my quick time bellhousing and custom side pipes.

    2. #22
      Join Date
      Sep 2010
      Location
      Beach Park IL
      Posts
      2,626
      Country Flag: United States
      In case images don't show up. https://www.m3post.com/forums/showthread.php?t=102981 Here's the M3 on a chassis dyno. Kansas has more peaks than this torque curve. So yeah, great engine for autocross.



      Go back to the OP. The 427 will be easier to drive than the 377, it makes more power everywhere, will require less maintenance, be more fun and driveable on the street and he won't have to regear the car to get it to dig off a slow corner
      Donny

      Support your local hot rod shop!

    3. #23
      Join Date
      Jan 2022
      Posts
      25

      yes

      I have everything set up already with my march serpentine pulley set up and my quick time bellhousing also my custom side pipes and I only autocross 10 times tops a year and I think it will just be easier to put a 396 up the the 454 blueprint maybe with fuel injection a couple of guys in the group I autocross with are very fast and run small block chevy motors and I am not trying to be the fastest guy out on the coarse .

    4. #24
      Join Date
      Nov 2018
      Posts
      538
      Country Flag: United States
      Quote Originally Posted by c3rocket View Post
      Thanks for the advice guys I only autocross this thing 10 times a year tops and what about a lsx 427 but I think I would still have to swap exhaust out.I auto cross with a fast bunch of guys and 2 of them have small block chevys and there about the fastest out there a ls would be nice but I would have to scrap all the stuff I all ready did for the car like a complete march serpentine pulley set up and my quick time bellhousing and custom side pipes.
      You'll have to swap the exhaust out with a big block anyway so I wouldn't let that stop you from doing an LS. A small block is EIIEEIIE, while an LS and a big block are both EIEIEIEI, with E being exhaust and I being intake. Your exhaust will not bolt to a big block. And, depending on how large your exhaust runners are you might need to change the exhaust anyway if you go with a big cube engine.

      If you're set on part re-use your best bet would be to stick with a small block. You could just do up an aluminum 400 small block and it'll bolt right into where your current engine is. Or, stroke the same 400 out to a 427. I've never used these guys before (their link was first in my search) so can't say they're good or bad, but they offer an aluminum small block 427 short block for 5500 bucks. And, Chevy Hardcore goes over their build that they claim is a streetable 600HP, but there's no dyno along with it. They did say you want an aftermarket 400 block for this as factory 400s are prone to cracking out when you stroke/bore them to the limit. For autocross, and just general fun-to-drive, I'd be looking at aftermarket aluminum anyway.
      2021 Durango R/T
      2008 Colorado beater
      2003 Dakota project-o-mobile

    5. #25
      Join Date
      Sep 2010
      Location
      Beach Park IL
      Posts
      2,626
      Country Flag: United States
      Big block was never on the table.

      Quote Originally Posted by c3rocket View Post
      I was thinking about a blue print 427 or 454 small block the 454 makes 580 hp at 6000 and 570 trq at 4600 .
      Donny

      Support your local hot rod shop!

    6. #26
      Join Date
      Sep 2014
      Posts
      21
      Country Flag: Canada
      Quote Originally Posted by dontlifttoshift View Post
      In case images don't show up. https://www.m3post.com/forums/showthread.php?t=102981 Here's the M3 on a chassis dyno. Kansas has more peaks than this torque curve. So yeah, great engine for autocross.
      Funny, because it is the car to have the SCCA's FS class where it routinely beats the Camaros and Mustangs in the class. You obviously haven't driven one.
      Short and wide 1965 GMC 910.

    7. #27
      Join Date
      Sep 2010
      Location
      Beach Park IL
      Posts
      2,626
      Country Flag: United States
      I have, along with the Mustang in FS trim and the Camaro 1LE trim in BS trim.

      Nonetheless, in your need to argue you inferred sarcasm where there wasn't any. My apparently unclear post agreed with your comment about how great the M3 engine is for autocross and it supports my assertation that a flat predictable torque curve is better to drive.
      Donny

      Support your local hot rod shop!

    8. #28
      Join Date
      Sep 2014
      Posts
      21
      Country Flag: Canada
      Quote Originally Posted by dontlifttoshift View Post
      Nonetheless, in your need to argue you inferred sarcasm where there wasn't any. My apparently unclear post agreed with your comment about how great the M3 engine is for autocross and it supports my assertation that a flat predictable torque curve is better to drive.
      Iím not trying to argue at all. You said that a destroked high revving engine canít have a flat torque curve and I disagreed.
      Short and wide 1965 GMC 910.

    9. #29
      Join Date
      Jan 2022
      Posts
      25

      my little 350 in my 66

      Well with out having to change any thing I really like the small block 454.I have a detuned little 350 making 600 hp and and 600 trq at 4300 and love it and its very manageable and predictable here it is .
      Attached Images Attached Images  

    10. #30
      Join Date
      Jan 2022
      Posts
      25
      The 454 small block will be close to that very user friendly.

    11. #31
      Join Date
      Oct 2004
      Posts
      2,499
      Country Flag: United States
      Vacuum on the BP SBC 427 and 454 are extremely low (values are listed on their dyno graphs). You'll likely need manual brakes, hydroboost, or a cam with less overlap. I would not be surprised if that's also the reason they don't offer the Sniper EFI as a package on that one (insufficient vacuum for speed density).

      On the 400 they claim 10.5" Hg @ 950rpm. Still low, but might work with power brakes. It's also offered with Sniper EFI. Torque is really flat and really wide. And if you went the EFI programmable timing map you can fine tune the power(take some out the bottom to soften it if necessary, or take some on the mid-range and really make the torque flat and predictable) even more. Or setup two tunes, so you have one specifically for autocross, and a second one for street/strip. The bore is the same size as the 427 and 454 so no bore valve shrouding. And it could rev a little quicker as it less stroke than the larger two.

      Since the image won't seem to post for me, I'll just post the link for reference: https://cdn.shopify.com/s/files/1/21...g?v=1626803310

      Red Forman: "The Mustang's front end is problematic; get yourself a Firebird."

    12. #32
      Join Date
      Jan 2022
      Posts
      25
      My car is manual brakes with a willwood big brake kit and will be using a e vac system for the crank case .I would run a fuel injection if I know it will not be a pain in the ass to fine tune .


    13. #33
      Join Date
      Nov 2018
      Posts
      538
      Country Flag: United States
      Quote Originally Posted by dontlifttoshift View Post
      Big block was never on the table.
      Missed a word - my bad.
      2021 Durango R/T
      2008 Colorado beater
      2003 Dakota project-o-mobile

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