A guide to building the lil guy. The Mighty 300

Discussion in 'Small Block Tech' started by Joe65SkylarkGS, Oct 27, 2009.

  1. Jim Blackwood

    Jim Blackwood Well-Known Member

    OK this is not a P76 block. I was told it was when it was shipped in but this is the first time I've taken any actual measurements. Guess John will be surprised. With a tape I measured 7-3/4" from the deck to the main bearing bore. That bore measured out to 2.485" (no insert). Which puts the deck real close to 9" even. The BOPR has a deck height of 8.96 and a main size of 2.3" Looks very much like this is a Rover 3.5L block but I'll have to look at the liners to be sure. Mains in the P76 block are 2.5495"

    Sorry that doesn't answer the question, I've had no luck with online searches. Might find out by asking some of the UK guys or Aussies.

  2. Alssb

    Alssb Well-Known Member

  3. Jim Blackwood

    Jim Blackwood Well-Known Member

    I asked on MGE and so far it looks like the P76 deck is somewhere between .100 and .125" taller. Which means as long as a P76 intake had a reasonably thick flange it could be shaved to fit the 300.

  4. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    There is probably enough material on the heads to take a little bit of that off if the flanges start getting to thin as well?
  5. aznriceninja

    aznriceninja Member

    Hello, new to Buick forums, I don’t mean to Hi-jack the thread but my friend is selling me a 65 300 for $200 one caveat, he yoinked the crankshaft for his 3.9 Rover stroker for his 62 skylark. Is there anyone in the California area with a spare 300 crank they are willing to sell? Or would it be beneficial to me to consider a 350 crank swap? I’m not looking for too crazy of a build considering this is for a possible future 4x4 Willy’s wagon
    300sbb_overkill likes this.
  6. Taller than a 215 engine or taller than a 300 engine?
  7. Jim Blackwood

    Jim Blackwood Well-Known Member

  8. Jim Blackwood

    Jim Blackwood Well-Known Member

    Got my heads back Saturday, here are some photos. Basic TA bare heads, no port or chamber work, standard sized seats. They have beehive springs as you can see, 1.6 and I think 1.9 intakes but I'd have to measure. I might have cut them a little over that. (the valve heads) The valves are titanium and had to be shortened, in the last photo you'll see the hardened steel lash caps that are required. Fitted with umbrella seals to help lubricate the valve stems. A light skim cut on the mating face of the heads to remove any scratches. I'll CC them maybe this week, then when I get the bore size and deck dimension I'll be ready to finalize a piston order.

    Spring pressures are about 145 seated and 350 at 1/2" lift, which should be acceptable for either a solid flat tappet or a solid roller I believe. Shooting for 7-7.5K without valve float.

    Valve lift will be 1/2" or less, duration around 215 probably.


    IMG_0009.JPG IMG_0010.JPG IMG_0011.JPG IMG_0012.JPG
    GraySky likes this.
  9. Joe65SkylarkGS

    Joe65SkylarkGS 462 ina 65 Lark / GN

    Good stuff in here guys
  10. Mart

    Mart Gold level member

    I like those heads, titainium valves & beehives. Looking good Jim.
    Last edited: Jun 30, 2020

    RUBBERRODDER Active Member

    Hey everybody!
    Its been a while since I have been on the board. I just picked up a set 0f '64 aluminum 300 heads that are rebuilt and install ready. I know these thing are getting hard to find in any condition just due to age and attrition. I got the 4bbl. manifold too.
    What are these heads going for now-a-days? I just just shelled out $300 for the heads, intake, and the "rottenchester" 4 gc carburetor. I just hope they don't end up shelf ornaments.
  12. Jim Blackwood

    Jim Blackwood Well-Known Member

    $300 for rebuildable heads, $250 for the 4bbl intake.

  13. GraySky

    GraySky Well-Known Member

    I picked up a complete '64 300 motor for my '63. I am cash strapped and trying to get the most out of it, so I thought I'd run it by you guys and see what you thought. If you want me to start another thread, let me know.
    We still need to go through the short block and check all the clearances, but it appears to be in decent condition. I hope to run it as is for now.
    I intend to get the heads checked out and minimal work done to them as needed. We might do a little porting (just mild bowl and port cleanup). I will need a decent spring setup. What would you recommend?
    Since this is a light car and I'm running a .373 Ford rear end, I thought I could get away with a little more cam with a decent stall converter. I was going to have comp grind a 224/230 on a 108 lobe center with lift in the .480 range. Everything I've read indicates that on valve size limited motors like this the narrow lobe centers will help maximize torque in the limited power band. Hopefully there will be enough valve to piston clearance. I want enough overlap to get things working, and I'm ok with a 3000-3500 stall converter. Dynamic compression should end up around 7.75:1, which is a little low for aluminum but not way out of line. Should run good on pump.
    What I'm really not sure about is the carb. I've got a couple 4-jets, but I'd like to go up in size a little. Fuel injection is also a possibility. I have the 4 barrel manifold, but I'm not really sure that it's the best piece for a performance engine. My dad and I were talking about building a throttle body injection unit and running Microsquirt on it. Could be fun.
    I think turbos would really wake this motor up, considering that it is really similar to the 231 in design. Maybe in the future a 78/75 and 10 pounds of boost, but right now we just want to get everything up and running.
    Any input is appreciated!
  14. sean Buick 76

    sean Buick 76 Buick Nut

    I would personally set it to 10:1 static compression, a custom turbo cam, and a well matched turbo, good pistons and rods would be smart at this point too.
  15. Jim Blackwood

    Jim Blackwood Well-Known Member

    Depends on what you want. I'm actually considering a stock cam for my next build, though it will have the Eaton blower. OTOH the GN owners go pretty nuts with boost.

  16. sean Buick 76

    sean Buick 76 Buick Nut

    We had a stock cam in a buick 350 with 9:1 compression, single turbo. It made amazing huge torque from 1500-4800 rpm. After 4800 it was falling flat. It was 455 hp and 460 feet of torque to the tires, ran low 11s.
  17. sean Buick 76

    sean Buick 76 Buick Nut

    A cam swap would build up both hp and tq up.
  18. Greg

    Greg Well-Known Member

    How does the intake port size on the TA heads compare to the iron 300/340 head? Same size? Smaller? Larger? Can an iron 300 4bbl intake work with the TA heads?

  19. Jim Blackwood

    Jim Blackwood Well-Known Member

    The TA intake ports are about 1/16" shorter than the irons but make that up on the width where they are uniform in size and the irons taper down on one end. And of course the exhaust ports are larger. Either iron or alloy intakes should seal to these heads without any drama.

  20. Greg

    Greg Well-Known Member

    Then port matching the TA heads with an iron 300 intake is not an issue. Corrrect?


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