Stock 72 350 HP, need a little more

Discussion in 'Small Block Tech' started by tubecatgs, Apr 7, 2017.

  1. tubecatgs

    tubecatgs Finally a 4 speed......

    Hey folks, I believe I have a stock 350 72 skylark 2 barrel in my Custom Convertible. All the documentation I see says it had about 155 HP from the factory. I already added a Holley 650 and TA aluminium 4 barrel intake (not the brand new one released). I assume this brought it up to about 180 HP....any guesses?

    I am adding TA Performance headers and 2.5 dual exhaust with H pipe. Any ideas on how much this would add?

    And lastly, I would like to get over 300 HP..... can I have this built to 70 specs with the high compression pistons or any other ideas for a budget build?

    Thanks, love this site you guys rock!
     
  2. alec296

    alec296 i need another buick

    Yes you could use higher compression Pistons. Cast 340p nets about 9.2 . Better Pistons would be forged autotec. Rated about 9.6. The crower level 3 cam would be good for unported heads. Porting and big valves will increase potential. But can open bigger cam options. The ta212 is ok , the TA 310 is ok but would like more compression.
    Do the oil mods to block and TA backgrooved cam bearing. Get a 5/8 pickup screen.
    You will need a 3series rear gear and atleast a 2500 small block rated torque converter.
    If the engine is solid good runner you could shave the heads .060 to get the compression up. Get .050 shorter pushrods. Crower cam. Porting heads. 750 Quadrajet built by Quadrajet Power. Open up intake runners some. Distributer recurve. Have you tuned/jetted the Holley for the 350? Vacuum secondary? And did you get a 4 barrel accelorater cable?
     
  3. tubecatgs

    tubecatgs Finally a 4 speed......

    A lot of great info... might be a little more than I can take on right now. Didn't know you could shave the heads.... That's a great idea...
    It's' a 4 speed car so i dont think an accelerator cable is an option?

    I know nothing about how to adjust the carb.... it was new and just slapped it on... Any ideas there would help as well. Thanks
     
  4. alec296

    alec296 i need another buick

    You would still need a 4 barrel accelorater cable no matter the trans. A 4 barrel has more travel then a 2 barrel. I am not a Holley person so best thing I can say is get an air/fuel meter wide band o2 in exhaust. It can tell you when it's too lean or rich. Automatic would have a downshift cable. Obviously you don't.. a recurve kit for distributer and a decent 3 series rear will definitely help no matter what you do later. Yes you can shave heads. If you have the original Pistons in still .060 should give around 42 cc head about 9.45 compression estimated. If you haven't brought headers yet, consider spending the money on head work and the cam. Can still get 300 hp with out headers.
     
  5. sean Buick 76

    sean Buick 76 Buick Nut

    I vote to do the grades like you were planning but have a good look you may need to re route the trans lines a but to keep them cool.

    I personally would just mill the heads like Alec suggested and I would use a TA 212 cam... Adding high compression pistons means a full rebuild and to do it right it costs $$$$. I also agree on the air fuel meter bring a good addition to help tune. Are there any shops around you that do a chassis dyno tune? That would be a really good idea in my opinion. Just be sure to find a shop that is comfortable working with carbs as many shops are EFI only... Dial in the carb and timing on the dyno and you should be happily ripping around burning rubber without touching the bottom end other than a cam swap...Good idea to change at least the front cam bearing and timing set too.
     
  6. LARRY70GS

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

    What is your ignition timing? Initial, and total advance at what RPM? Are you using the original distributor, part number 1112109?
     
  7. tubecatgs

    tubecatgs Finally a 4 speed......

    I don't remember the timing... what should it be? Pretty sure it's the stock distributor. However, the folks that had it before me swapped the points for a bolt in electronic ignition set up that just replaced the points in the stock distributor only.

    If I have the heads milled to remove .060 and I buy .050 shorter push rods does this affect the intake fit and gasket set?

    So to sum up some of these great ideas:
    1) mill the heads down .060
    2) shorter push rods by .050
    3) replace Cam with maybe TA 212 and timing set and replace cam bearings.
    4) headers with 2.5 dual exhaust
    5) take to a shop to dyno tune with carb
    6) make sure I have the right 4 barrel accelerator cable ( I think I swapped it when I put the Holley in)

    Sorry for my inexperience but additional questions
    What is a distributor recurve?
    What should timing be?
    What do you guys mean by "decent 3 series rear"? Do you mean rearend?
    What is or do you mean by an air fuel meter in the exhaust? Is this a permanent install?

    Please remember is a 4 speed car with 68 Muncie M20.

    Thanks all!
     
    Last edited: Apr 18, 2017
  8. sean Buick 76

    sean Buick 76 Buick Nut

    A distributor re curve is simply changing how quick the mechanical advance raises the timing. At idle the timing is set at an "initial" setting of about 6 degrees however as the RPM is raised there are mechanical weights and springs in the distributor that advance the timing to roughly 30 degrees. On top of that there is a vacuum advance canister that adds more timing under light throttle situations to improve fuel mileage. But at full throttle the vacuum advance does not add timing.

    The factory settings leave much to be desired and here are a few ways that the "re curving" of the distributor can help.

    1. The initial timing is too low to give the best off idle transition and low RPM torque. The problem is if we just raise the initial timing then there is too much max "total" timing at the higher RPM and that will cause detonation and engine damage. So to solve this I use a Mr Gasket bushing kit to reduce the amount of timing that the mechanical advance gives. I then set the initial timing at about 12-14 degrees and a max or "total" timing of about 32-36 degrees depending on the combo.

    Then I experiment with different springs in the mechanical advance using a Crane cams kit. I shoot for the total timing to be all in by 2200 RPM but it can be different for each combo.

    Then moving into the vacuum advance canister I use the Crane cams adjustable version that comes with the springs I talked about above. I limit the vacuum advance to just 10 degrees and then adjust it to come in nice and quick off a ported vacuum source on the carb which just means a line that only has vacuum at part throttle.

    Regarding the rear end ratio of "3 series" that's just referring to a ring and pinion ratio of 3.08, 3.42, or 3.73 which would give better off the line acceleration over a 2 series gear like a 2.56 or 2.73 gear that most if these cars came stock with. Higher numerical number is better for acceleration but gives higher Highway RPM and less fuel mileage at high speeds.

    I would do one thing at a time and keep the car on the road instead of doing too many projects at once...

    So the engine and later so the rear end or the other way around... There is a two letter digit code on the rear end on the right side that will tell us what the gear ratio is... If you wire brush the axle tube on the passenger side you will likely see the two letters... Tell us those letters and we can tell you the ratio.

    Yes the intake fitment may be an issue if you mill the heads, but most good shops know how to either mill the intake to match or mill the head surface where it bolts to the intake to keep things lining up ok.
     
  9. sean Buick 76

    sean Buick 76 Buick Nut

    Oh and for the air/fuel meter you can either do a permanent instal or a temp setup. The innovative LM-2 for example can just be plugged into the tail pipe and it can monitor the air fuel ratio. Or you can weld a bung into the exhaust close to the header or manifold for a permanent instal. I have an air fuel meter on both exhaust pipes, and also a throttle position sensor so I have my air/fuel meter box also getting information such as throttle position, and also RPM and I can datalog this and upload it to a computer to see which rpm and throttle positions are rich or lean. I have turbos on my 350 though do I need extra tuning ability over normal setups but the same things apply.
     
  10. tubecatgs

    tubecatgs Finally a 4 speed......

    Wow, good sfuff.. a lot to think about. Already planned on redoing the rear end because it leaks. I will see it I can get the number tomorrow. I already ordered the headers and will start talking to shops in the area about milling the heads and take my time and do it right.. Thanks again.
     
  11. sean Buick 76

    sean Buick 76 Buick Nut

    Is it leaking from the cover or from the front seal? Do you know if you have limited slip?
     
  12. alec296

    alec296 i need another buick

    The ta212 like big valves and/ or porting.
    The crower level 3 cam is king on stock heads. If you push .070 on heads for possible 9.78. with a retarded crower . It has proven to be a lower 13 second setup with 3.42 and auto trans. The 212 has been pushed to 350 hp. With the right choice of Pistons and quench. The ta310 has outran both with near 10 to 1 and porting and headers. Carb jetting and timing will factor output . 4 Speed can like 3.73 or deeper gears which would be more like a 310 or 212 cam..
     
  13. LARRY70GS

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

    Ignition timing can make a huge difference. You need to verify what distributor is installed. The stock 350-2 distributor in 1972 was the 1112109. The part number is stamped into the circumference of the distributor below the cap. That distributor only has 12-16* of mechanical advance. Stock initial timing was specified as 4* BTDC. That means at WOT, total timing would be 16-20*. That's far short of the 30-34* necessary for best power. Buy or borrow a timing light and check the timing.

    http://www.v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/
     
    Last edited: Apr 9, 2017
    matt68gs400 likes this.
  14. tubecatgs

    tubecatgs Finally a 4 speed......

    From the front seal. I have springs and shock to put it so I was thinking of just pulling the rear and have someone go through it and maybe rebuild and convert to posi.
     
  15. sean Buick 76

    sean Buick 76 Buick Nut

    Before picking a rear gear ratio I would find out if you have a close or wide ratio trans gearing.
     
    Last edited: Apr 10, 2017
  16. tubecatgs

    tubecatgs Finally a 4 speed......

    M29 5.jpg M 20 6.jpg M 20 4.jpg Yeah, thanks. Have the rear out, gonna try to pull the trans tonight. I took these about 3 years ago before I installed it. does this give us any idea of the ratio/gears? Thanks
     
  17. Mart

    Mart Gold level member

    Look at the input shaft. No or one groove is an M-20, two grooves are M-21. Definitely not an M-22.
     
  18. tubecatgs

    tubecatgs Finally a 4 speed......

    Pulled Muncie and input has 2 grooves. Pretty sure it's a 68/69 m20. Going to drop that off tomorrow to have that and the rear rebuilt. Builder was thinking of installing posi 3.23 gears for me.

    After I pulled the tranny and rear I might as well pull the motor and think about making these engine upgrades sooner that later since it looks like I have a slight rear main oil leak and a leak in the front.

    Anyone know of a good Buick engine builder in Western N.Y. that might be skilled to shave the heads and intake to match? Thanks guys!
     
    Last edited: Apr 18, 2017
  19. alec296

    alec296 i need another buick

    Shave the intake face of the head not the intake. And you may not need that as the big issue is the bolt holes. Open the 4 corner ones towards the bottom. Then snug bolts down slowly it should bring the rest to line up
     
  20. tubecatgs

    tubecatgs Finally a 4 speed......

    Ok, reared is being rebuilt with posi 3.42 gears. Muncie is being rebuilt/resealed. The TA headers and 2.5 dual exhaust were ordered a while ago and in my shop. There has been great advice here ( thanks all) and here is what i think i am going to do since its a good running motor and just want a little more pep without breaking the bank.

    1) mill the heads down .060
    2) shorter push rods by .050
    3) replace Cam with maybe TA 212 or crower and replace cam bearings.
    4) headers with 2.5 dual exhaust
    5) new lifters
    6) new timing set
    7) replace main seals
    8) look into distributor upgrades/power timing
    9) take to shop to dyno tune and set carb.

    Last 3 questions for now.

    1) I see mentions of TA 212 cam and Crower level 3 cam. Since I am not porting the heads or changing the valves... which is better and what model number is the crower cam (can't find it)?

    2) oh and I forgot about the oil mods? Do I just buy a 5/8 pickup tube or do I need to drill out the heads and block to handle better oil flow?

    3) any idea of how much HP I will gain from all the above? I am hoping for additional 40 to 50 if I am lucky.

    It's a hobby car that I take to cruise nights and the kids for an occasional ride etc.

    Thanks again!
     
    Last edited: Apr 20, 2017

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