454 build with stock 781 heads

Discussion in 'High Performance Modifications' started by Philly, Dec 31, 2011.

  1. Philly

    Philly Veteran Member

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    Ok guys i really need to pick your brains now that i'm starting to buy parts for my engine. My plans have changed for my engine since i started building my car due to the fact that i have a baby on the way & I'm finding out that cars cost lotsa cash..lol

    Heres what i have so far.

    454
    stock crank/ rods (will be resized)
    RPM performer intake
    going with hydrollic roller (already getting the rollers)

    New domed pistons most likely .030 over due to some wear to bump the compression to 10:1 Yes i will get some nice decent pistons


    STOCK 781 heads, stock valves..I pretty sure these are gonna be ok. I probably wont have the cash to do the bigger valves etc etc or buy new heads so these are what i decide to use. I will clean them nicely

    OK heres where i need some help.


    CAM/ springs/ whatever i need???? no clue I'd like to have it idle a bit rough but get the most horspower possible.

    CARB??? Not sure what size to get to go with what the rest of the combo is.

    Headers? What size?/ make?


    1 more question...What kind of HP will you think this will give me? I'd really like to get as much as possible with this engine/ build.

    Anything else should i be buying to suit this particular engine build keeping in mind "best bang for the buck"?.

    Thanks guys:cool:
     
    Last edited: Dec 31, 2011
  2. 5spd540

    5spd540 Veteran Member Lifetime Gold Member

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    781s are good street heads I made just shy 500 hp on a 496 with a set last year
     
  3. HOLESHOT

    HOLESHOT Veteran Member

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    i made 563hp with them just under 700 on a shot. i run a 950 carb an a 635-637 lift cam
     
    Last edited: Dec 31, 2011
  4. yenkomike

    yenkomike Member

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    15 years ago ibuilt a few of those engines and they ran good. i used stock lower ends with 11 to 1 closed chamber pistons and stock 781 heads with just a valve job and good springs. 2 of them i ran a solid flat tappet elgin cam 258/268 at .050 with 595/621 lift with a good intake and an 850 and 1 7/8 headers they whould run 11.40 to 11.60s on pump gas with a full chevelle and 4.10 gears and a 10 inch convertor. we ran them hard and they were good engines. i think now with the better cams i think you can run better yet with one. good luck
     
  5. Philly

    Philly Veteran Member

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    Thank you for the honesty and insight. Its really appreciated. How far down I-75 are you from the Sault?
     
  6. yenkomike

    yenkomike Member

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    im south of lapeer . so quit a ways. i dont think running low 11s to high 10s in a full weight car is out of the question.with a modern cam and a little clean up of the port in the bowl area all the ones we did were bone stock ports.there are some guys making huge power with them heads with some port work and bigger valves.
     
  7. 450bench

    450bench Veteran Member

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    I have run a couple of Herbert hydraulic rollers in 10 to 1 454s with 781 and 049 heads...the 244/244 642/642 hydraulic roller on a 108 centerline was as good a cam as I have ever run...I even ran it with solid rollers, which you can do, just lash at 16/18...I ran it with a Holley 800 dp and an old Edelbrock street master port matched intake...Terrific camshaft

    One thing to take very seriously is stock spring height with 781s...Older bbc heads set up at 1.88...I've seen 781s set up, stock, as low as 1.82...By all means, check it...A set of +.050 keepers will fix that issue

    Again, the Herbert cam I mentioned is superb
     
  8. 54inches

    54inches New Member

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    Good to know, building one for my suburban, mud truck, in the future. I have 049s and some non-performance non-peanut heads. Going to port the 049s and have them cut for larger valves, etc, etc......

    Did you have any vacuum issues with the cam?
     
  9. Philly

    Philly Veteran Member

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    Awesome info. Thank you.:cool:

    If i ran the hydrolic roller would the stock spring height still be an issue or was that issue only with the solid rollers only?
     
  10. JONESYFXR

    JONESYFXR Veteran Member

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    My brother in law is running a 461 in a 72 Chevelle. He is at 12.1 comp with a stock GM forged 454 crank with forged I-beam rods, a hydraulic roller with bowl ported 781's with stock sized valves and we figure he's right around 525hp easily.

    The engine has never been on a dyno, but that's what we conservatively figure he's at.
     
    Last edited: Jan 1, 2012

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