What would you do for refreshing a 66k 350?

Discussion in 'Small Block Tech' started by JN_Skylark, Nov 2, 2020.

  1. JN_Skylark

    JN_Skylark Well-Known Member

    Hello everyone,

    As we are getting into fall I'm considering on doing a small refresh on my 1969 Skylark's engine and transmission over the winter. I haven't had any issues with either the engine or the transmission apart from both leaking oil, which is the main reason why I'd like to refresh the engine and transmission by replacing gaskets and seals at a minimum.

    However, I'm sure we're all familiar with the "While I'm in there" logic of replacing parts, what are some things that I can give attention to without tearing the whole engine apart? The engine runs very nicely and the transmission shifts smoothly so a complete rebuild is unnecessary at this point, but what would you guys recommend I do when I get around to doing said refresh?

    My loose plan so far is as follows:
    - Engine seals/gaskets
    - Head gaskets? (I recently did a compression test and the engine seemed healthy, 150 psi average with a couple cylinders around 140 or so)
    - Replace timing set?
    - Fuel pump?
    - Oil pump?
    - Replace TH350 external seals
    - Replace TH350 pan gasket and filter

    Vehicle Specs:
    1969 Skylark Custom
    350 4 Barrel with Factory AC
    Equipped with Holley 4175, but I'm rebuilding a Quadrajet to replace it with help from Cliff's Performance
    TH350 transmission
    2.93 Open Differential

    I'll also admit I am tempted to hop up the engine a little bit with a cam upgrade, would a TA 112 be a good choice for a stock engine/stock converter application? I'm perfectly happy with the way the car drives and cruises down the road in its current state, the car is driven very frequently so something with smooth idle and good economy is what I'm looking for.

    Anyway, enough of my talk. Let me know what you guys think

  2. alec296

    alec296 i need another buick

    Timing chain and gears, leave the rest alone. If your gonna change the cam , 69 4 barrel engine if factory should be 9.2 actual compression. If your gonna go that route, get a ta backgrooved front cam bearing, and drill out oil pickup passage in block, use the bigger oil pickup tube. Higher rpm need more oil pressure at the higher rpm
    Gold GS, BUICKRAT and 72gs4spd like this.
  3. 72gs4spd

    72gs4spd Well-Known Member

    Would also be a
    Good idea to inspect oil pump and add at least new gears, booster plate & set clearance.
    JN_Skylark, Gold GS and DasRottweiler like this.
  4. Mark Demko

    Mark Demko Well-Known Member

    A GOOD valve job
  5. Schurkey

    Schurkey Silver Level contributor

    It's tempting to say "change the oil, and shut the hood".

    Perform a cylinder leakage test; if the valves aren't leaking, and the guides aren't worn...you don't need a valve job. You'll find out about the guides when you remove the heads to replace the head gaskets, and remove the valve springs to replace the stem seals.

    Yes. All of 'em. Including valve stem seals. Consider replacing the core plugs. IF (big IF) you have block drains, consider removing the OEM plugs in favor of brass draincocks. Chisel all the carbon out of the exhaust crossover ports and the intake passage while the intake is off. Don't forget to pull a couple of lifters to inspect for wear. Put each of them back in the same bore it came out of.

    Fresh oil and filter
    Fresh coolant
    Flush the PS fluid
    Fresh air and PCV filters, maybe PCV valve
    Fresh vacuum hoses
    Fresh fuel filter, consider replacing all the rubber fuel hoses on the suction side of the fuel pump. (There shouldn't be any rubber hose on the pressure side of the pump.)
    Yes. The thinnest you can find.
    Yes. Degree the cam.
    Not unless it's giving you trouble.
    Might as well INSPECT the pump, and set the end-clearance since the timing cover is coming off anyway.
    Sure. While the engine is out, consider a mild upgrade to the torque converter (or a complete overdrive automatic transmission.) Watch for a cracked dipstick tube at the rolled indentation for the O-ring. I've been known to put double O-rings on the modulator. If you don't replace the converter, after changing the filter, dump 5 quarts of fluid in the pan, drop a cooler tube into a drain pan, start the engine. Pour fluid down the dipstick tube as fast as you can, until the fluid coming out the cooler tube looks virgin-fresh. Re connect cooler tube, top off trans fluid as needed. You'll want 12--15 quarts of fluid in total to flush the trans.

    Might as well change gear lube, too. Consider making plans for a limited-slip and somewhat higher-numerical gears.

    Leave the cam alone unless your inspection shows wear. Tune the carb, curve the distributor centrifugal and vacuum advance.
    Last edited: Nov 3, 2020
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  6. JN_Skylark

    JN_Skylark Well-Known Member

    Thanks Schurkey,

    Your plan sounds about right, not a complete rebuild but a mild refresh. The car isn't going to be a hot rod so the cam will stay stock unless I find abnormal wear on the lifters. I also realize it's been a month since your reply but work and school have been kicking me in the butt!

    Thanks again for the advice!
  7. JN_Skylark

    JN_Skylark Well-Known Member

    Also what stall speed would you recommend if I do decide to upgrade the converter?
  8. alec296

    alec296 i need another buick

    Depends on cam . The 112 I would say a 2000-2200. Small block rated torque converter.
    But with your compression, I personally like the crower level 3 cam. 2200 would be ok but 24-2500 would be a little more fun. I would say the ta 284-88 but someone else recently got one and duration is way different now, more duration, it may not have the same low end as it did.
  9. JN_Skylark

    JN_Skylark Well-Known Member

    For a stock camshaft it really wouldn't be worth it to upgrade the torque converter would it? I've looked at some of the cams that TA offers but that's not something I'm looking to change just yet unless of course I find worn components that warrant a replacement, if I had to I think the 112 would be a good choice for my application but that's something out if my expertise.
  10. alec296

    alec296 i need another buick

    A 2000-2200 small block rated torque converter would show improvement all around even on a stock cam. The 112 is similar to stock power range . Get a distributor recurve kit,
    I stick with my previous suggestions on cam and converter.
    But take a look at the 284-88 cam.
    Fox's Den likes this.
  11. Fox's Den

    Fox's Den 27 years of racing the same 355 Buick motor

    ^^ I agree I would stick in that much convertor no matter what cam I started with on the smaller side It will just run so much better Give you that 455 launch out of the hole

    Most races are won off the line so plan accordingly.
    alec296 likes this.
  12. sean Buick 76

    sean Buick 76 Buick Nut

    There was a guy who did a bunch of quarter mile testing starting with a stock engine and drivetrain. He found a large gain going to a 3000 stall converter even with a completely stock engine.
  13. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    If you're not looking to horse it up, I'd leave well enough alone. If it's running good then fix the leaky gaskets and paint it. No need to replace what isn't broken.

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