What year Big Block Buick to Build?

Discussion in 'Buick FAQ' started by Nicholas Sloop, Jan 25, 2007.

  1. Nicholas Sloop

    Nicholas Sloop '08 GS Nats BSA runner up

    I thought about suggesting that, but every 70-up 455 still has the passage on the driver's side, and I've only heard of one instance where someone suggested that oil was seeping out through the head gasket (and I am skeptical of that).
  2. Stubbe

    Stubbe Stubbe

    Ok, I have a question then. I have a 75 block with 73 heads. I know its lower compression because of the piston dish. What spec pistons would I have to put in to raise the compression to 10:1 or so. Also does this lower compression really affect my perfomance that much.
  3. SwedishGS455-71

    SwedishGS455-71 Well-Known Member

    Hmmm are the 75 heads "really" pieces of crap.
    Can't they be used in a boosted car. Turbo/compressor setup, due to the low compression??

    I have a couple of them heads. Dont know what to do with them though.......anchors maybe :laugh:

    // Jan
    Last edited: Aug 22, 2007
  4. mcmain0121

    mcmain0121 Member

    Unless I missed it in this thread, what about having the '75-'76 (less desirable) heads milled down some to increase combustion? Is there enough material there to allow for this?

    Sidenote; great site, excellent info! :beers2: I am used to a couple other sites that are HIGHLY technical so I had big expectations. So far, my expectations have been met. Continue the great work gentleman.:TU:
  5. moleary

    moleary GOD Bless America

    no, scrap heap those huge chamber heads, by the time you cut them down to get a good cc, your valves would rub through the pistons into the crank:bla:

    I may have a set of 70 heads I would be willing to part with:beers2: :dollar: They need rebuild.
  6. Nicholas Sloop

    Nicholas Sloop '08 GS Nats BSA runner up

    Not to mention the combustion chamber shape is bad, which milling wouldn't help.
  7. I have a 72 455. If I read your sonopsis correctly I can have the heads reworked with bigger valves and do some porting and I will have basically a stage 1 motor. What about the cam are they all the same between a
    Stage1 and a non stage1?
  8. Nicholas Sloop

    Nicholas Sloop '08 GS Nats BSA runner up

    Actually, just the bigger valves and you've got pretty much a Stage 1 motor. Porting is icing on the cake.
    From the factory the Stage 1 used a bigger cam, but you would not want to use either in an engine today. Technology has given us much better cams, and the stock Stage 1 cam is still very mild compared to what you can get today, with no downsides.
  9. electradirtcar

    electradirtcar Active Member

    great post it answered a lot of questions i had i run a 73 lectra 225 on a 1/4 mile dirt track (worlds largest dirt car) it is a stock class last year i snuck in a little hotter cam 496 lift comp cam and it really helped . Next year we will be required to run a holley 500 2 barrell . keeping this in mind would i be better off to use the non stage 1 valves I am planning on building a new motor for next year and thought i neede a 70 model block and heads until i read your post any inside tips someone might have would be appreciated I need the most power I can get from a stock appearing engine we are requred to pull 16 inches of vacum at 850 rpms thanks for any info anyone might have
  10. twolfinger

    twolfinger Fly Eagles Fly

    I am looking at buying a complete carb to pan 455. Comes with headers and is recently a stock rebuild. the block is a 72 by the casting, intake is 73 and heads are the 75-76 that you guys are blasting as being poor? He wants 700 for the whole setup, am I wrong in thinking I should be able to get this for 400? He originally bought it thinking it was a Pontiac engine and now can't use it as he wants the correct pontiac engine.

    If I keep the 75 heads on it, how much hp should I expect to get out of the engine if I throw a mild streetable cam?

    Great post, thanks for the info.
  11. bob k. mando

    bob k. mando Guest

    is recently a stock rebuild.

    is the rebuilder a known Buick guy? if he did a "Chevy" rebuild on it that engine is probably a grenade waiting to go off.

    If I keep the 75 heads on it, how much hp should I expect to get out of the engine if I throw a mild streetable cam?

    hard to say as we don't have any idea what pistons are in it. i wouldn't expect a whole lot out of it unless you plumb it for nitrous or a turbo or something.
  12. jarrett

    jarrett Well-Known Member

    Did you break the lifter bore running a flat tappet, or roller? Thanks, J
  13. KRL077

    KRL077 Well-Known Member


    Any chance you could post or pm me the link to your timing thread please?
  14. Nicholas Sloop

    Nicholas Sloop '08 GS Nats BSA runner up

    Ummmmm... It's right below this thread, in the Buick FAQ section. Power timing your Buick V8
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

  16. Tothna

    Tothna Well-Known Member

    I pulled the motor out of my stock 68 GS400 to rebuild and put in my brothers freshly rebuilt 69 GS400 motor (which I believe was kept pretty much stock) to keep my car up and running while I built mine. I used my stock carb on his motor and it never seemed to run just right. It didn't run horrible, but it didn't seem all that great either.

    Is there a compatibility issue with running a 68 q-jet on a 69 intake?
  17. DaWildcat

    DaWildcat Platinum Level Contributor

    Should be no problem at all.

  18. OlySezHey

    OlySezHey Lord willing...

    Does this info apply to nailheads too? I got a '65 401. Thanx :)
  19. storie585

    storie585 Well-Known Member

    Ok here is a stupid question.. why was the "SF" motor rated at 370 hp??.. I pulled one fron a 70 Riv and that is what I'm running in my 71 Skylark..
  20. DaWildcat

    DaWildcat Platinum Level Contributor

    In '70 the big car 455 was rated at the 370 number for marketing. To make the A-body cars seem a little safer they were rated at a lower rpm, thus less output.

    Or so the story goes, anyway. I don't put any weight in factory ratings to begin with.


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