My 350 Build

Discussion in 'Small Block Tech' started by Brian350skylark, Jul 7, 2013.

  1. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    Well the engine is still at the machine shop but i found some old pictures of the tear down and decided to start my own thread to help me keep track of it. After reading alot of your guys builds it inspired me to make my own :grin: The engine is a 1970 350 4bbl with standard compression. I bought it and a th 350 trans for $250 from someone on Craigslist which was of course "running" when pulled. I dont know how long the engine sat but didnt bother me much because i bought it to rebuild from the bottom Up. The plan for it is just getting it honed and the machinist building the short block using the stock rotating assembly. The plan is a good street engine with some decent strip ability with an edlebrock 750cfm carb (currently on car), ta 290-94h-350, heads and intake gasket matched and cleaned up with stock valves(now oversized) new springs, factory rockers, hooker headers with duel exhaust, pertronix ignition, 2800 stall converter and eventually 3.42 rear with posi. Here we go!

    This is the block right after it got dropped off at my house:


    The tear down begins! and so do the problems!
    if you can see one of the cylinders has water in it! It didnt seem to be sitting like that too long as there was very little surface rust that was easily wiped off.

    The block is stripped!

    other then that one cylinder everything else looked to be in good condition all the bearings were good nothing else looked funny.

    Heads, Cam, Intake..
    Just for the record, the engine was disassembled outside but it will be put together in a (fairly) clean garage. More to come hopfully soon!

    ---------- Post added at 10:02 PM ---------- Previous post was at 10:00 PM ----------
    Polished and cleaned up Ta intake Thanks to Nick White!
    Last edited: Sep 6, 2013
  2. ronbz455

    ronbz455 Big Butz Racing

    Cool keep us informed!
  3. alec296

    alec296 i need another buick

    make sure you .look up all the oil mods for block so motor holds up . looks like it had steel shim head gaskets which should be 020 thick, replacements will be 040 at least so you will loose compression there my opinion would be you will need alittle more compression ,a good port job and alittle more convertor with that cam. most convertors will run at the lower end of advertise on small blocks have someone degree cam and most stock single roller timing chains will retard cam so get a good chain I have a set of 10 to 1 stock 70 sp pistons and rods if block don't need to be bored over
  4. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    Are all the oil mods necessary? which ones should i definitely do and any links? i was planning on using steel shim gaskets again just for the heads, i did have a thought though, since the replacements are .040 is it possible to mill the heads .020, get the same compression ratio and not have to get adjustable push rods? Thanks for the advice on the stall converter how much more do you think ill need?
  5. sean Buick 76

    sean Buick 76 Buick Nut

    The 350 oiling system is not terrible like the 455... The oiling mods are not really needed in my opinion unless you are revving over 6000 RPM and or making over 450 HP.

    Sure, use the 40 thou gaskets and mill the heads 20 thou... Or mill the heads 70 thou and use adjustable pushrods and have higher compression to match the 290 cam...

    Ditch the 750 Edelbrock, go with a Q jet from Everyday Performance... or a 750 Holley if you want bad fuel mileage.

    I would use a 2800 stall converter with that cam.
  6. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    If you mill the heads, be sure and get the intake flange of the HEADS also milled to compensate. Don't be the guy who ruins an intake by milling it to match the heads.
  7. alec296

    alec296 i need another buick

    I think 1 of the posts at the top of small block forum here has the oil mods in it. the sump is the first 1 I do. that would be the long 1 in block from the pick up tube to oil pump housing. drill this to at least 1/2 in but I believe you can go to 9/16 on it,then get a replacement pickup tube which I think is actually 5/8. then drill out main crank feeds on #2,3,4 but not sure on size. also the passage in oil pump housing to 1/2 . I believe sean has this info in his book also. as far as convertor I would guess you will need something close to 2600-2800 so either get a custom built convertor or get something advertised for small block 3000-3200 should net atleast 2600 . I used a few tci convertors advertised up to 2800 on my buick 350 and got around 2300-2400 and 1800-2200- got about 1800 . you could deck heads or block the 020 over the gasket issue and you shouldn't need adjustable pushrods unless you take off 050 or more , or the cam base circle is different..
  8. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    but i dont have to do that if i mill the heads .020 and use .040 gaskets correct?
  9. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    I would say no if just .020". If I remember correctly, I had .040 shaved off a set of ported heads I ran years ago and the stock intake fit fine.
  10. sean Buick 76

    sean Buick 76 Buick Nut

    Correct the intake will fit the same as it did before.
  11. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    ok cool it wouldnt make sence if it fit to me but just wanted to make sure.
  12. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    It's .020" either way you slice it. .040 - .020 = .020
    Use the .040" gasket instead of the .020" steel gasket adds .020", shave off the same amount from head and you're at the same place you started with the steel gasket.

    Some here would suggest zero'ing the deck, or get it close to zero, then worry about what you need to take from the heads based on the compression you want. That cam will need higher compression to be optimal on the same premium grade pump gas.

    TA 290-94H .476/.486 lift @1.55, 226*/235* @ .050", 290*/294* advertised, default lobe center for 350: 110*, advertised power band for 455: 2200-5200 RPM, overlap @ .050" is 10.5*, SCR @7.96:1 DCR: 10.5:1

    Using some data I gathered from another post I had with deck zero'ing and SCR vs DCR for intake cam lobe duration, as an example:
    TA's "10:1" cast pistons should sit about .020 in the hole with their standard compression height pistons, yielding a true 10:1 comp. Zero'ing the deck will put it at about 10.25:1, and shaving .010" off the heads plus using your .040" head gasket will put you right at 10.5:1 static compression. This will be about the limit for the composite head gasket, or so I've read.

    This combination will be pretty borderline for streetability, with a pretty choppy idle.
    Head work, stage 1 valves, and headers are highly recommended.
  13. alec296

    alec296 i need another buick

    I suggest taking it off the deck as the bore is larger then chamber 040 off block bump comp and the thicker gaskets take up rest
  14. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    but the whole point of doing this was to keep stock pushrods, by taking 040 off the block that doesnt add up, ta has the cam listed for 9.0:1 or more CR, replacing the pistons isnt in my budget, and the block work is in progress, ide rather play with the heads then the block for some reason. Will this cam do alright with my set up and 9 to 1 compression? is it a must for 10 to 1? The goal is to have a respectable street engine that does well with pump gas. To be a cruiser with with some cojones.
    Reidk likes this.
  15. Mark Demko

    Mark Demko Well-Known Member

    I think the TA 290-94 cam would run well at 9.0 to 1 compression. :grin:
  16. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Zero decking the block also forces the charge into the center of the combustion chamber and makes the engine less octane sensitive. Pushrods are cheap. By the way, don't use the heavy adjustable push rods, order the correct length in chromoly.
    9 to1 is to low for that cam. Will blubber and run like a dog below 3 grand.
    Also, the factory 9 to1 rating is at zero deck. If it was not at zero to start you were not even at 9 to 1. If you CC everything you will see what I mean.
  17. alec296

    alec296 i need another buick

    020 isn't gonna affect your pushrods the lifter do have some "room" and you get 020 back with thicker head gaskets yes the cam will work but don't forget that everything you do on the car(cam,gear,compression,carb,convertor,size of exhaust) works well with the rite combination and tuning. if the car doesn't respond they way it should something may fit the combo, and just because you get a "750"carb doesn't mean it has the rite jetting or metering for your engine combo. you will have to tune this to get it to work right .
  18. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    i understand that but i have to start somewhere! ive seen alot of mixed opinions on the compression needed for this cam now i dont know what to think. Also remember this is california gas 91 is as good as its gets for me
  19. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Ever wonder why the cam description includes a recommended static compression ratio? Dynamic compression is why. What is dynamic compression? First you have to read this,

    The above site has a downloadable calculator at the end of the article. You can use it to calculate the dynamic compression ratio for any engine and cam, but, you must know your measurements. Forget about Buick's advertised compression ratios, you have to measure to know for sure.

    I used the calculator to figure the DCR on a 9.0:1`SBB using the 290-94H cam installed 4* advanced on a 106 ICL. It came out to 6.89. The target is for 7.5-8.4, but in reality, it is better to shoot for 7.9-8.0. A real 10.0:1 static compression gets you to 7.59 DCR.

    Read the linked article. Hope it helps. I've posted it at least a dozen times in the past.
  20. gsjohnny1

    gsjohnny1 Well-Known Member

    I see an issue with the dcr/scr theory. it does not mention anything about intaking and exhausting. for instance, what is the difference if you had briggs stratton valves vs stage 1 valves or a one vs 2 vs 4 barrel or multiple carbs or various intakes or turbo/supercharging. how do you make that formula work with those differences?

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