Next step for my 350

Discussion in 'Small Block Tech' started by UNDERDOG350, Jan 24, 2015.

  1. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    I've got a set of 72 heads that I'll be installing the larger TA stainless valves in and also have a new Crower level 4 cam ready to go in.
    I'll be fitting some beehive springs from Comp to lighten the load on the cam a little. Wanted to use the new conical springs but the pressure on them is too high.
    I'm going to have these heads milled to the same chamber size (58cc) I have now so the compression should be very similar. Hoping to pick up a couple more RPM if the stock manifold doesn't choke it all off.
    Anyone have a cosmetically challenged TA dual plane they want to sell? I'd like to experiment with it a little/lot.

    Would like to have it together for Norwalk/BPG in spring time.
    Last edited: Jan 24, 2015
  2. alec296

    alec296 i need another buick

    I like where your going with this Steve. I am contemplating the same cam in my convertible to have at race day.I have a 70 sp hi comp engine with ported heads shaved .025 standard valves port matched ta intake. Running the 310 cam now but car needs interior and wiring. Did ground up. No clue how engine will run.
  3. sean Buick 76

    sean Buick 76 Buick Nut

    Just wait for the single plane ta intake, it will be a big gain I think.
  4. alec296

    alec296 i need another buick

    "Race day". Intake won't be here for it. Those of us that want to go to Norwalk have to do without.
  5. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Hi Steve, how's it been? Just in case you're not aware, the IVC point on the Crower level 4 (assuming it's the Ultra Performance Compu-Pro part #50259 cam) is at 70* (when installed @0* and 4*A built into the cam), close to the Federal Mogul stock cam's 71*, which means you'll need a bit more compression to match what you had with that Crower level 3 cam.

    To get your ideal DCR, you'll need 10.15:1 SCR when installed as described above:

    Static compression ratio of 10.15:1.
    Effective stroke is 2.84 inches.
    Your dynamic compression ratio is 7.75:1 .
    Your dynamic cranking pressure is 152.55 PSI.

    If you feel more comfortable with less DCR, say around 7.5:1, you'll need 9.81:1 SCR:

    Static compression ratio of 9.81:1.
    Effective stroke is 2.84 inches.
    Your dynamic compression ratio is 7.50:1 .
    Your dynamic cranking pressure is 146.16 PSI.

  6. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Single plane would be a huge difference but looking to stay stock appearing thus the search for a TA dual plane to play with.

    Hi Gary, thanks for the info. I actually would not mind a small decrease in compression to tolerate straight 94 octane. I usually add a couple gallons of 110 to the 94 now just to be safe. I think I'll still have enough comp. to run this cam.
  7. killrbuick66455

    killrbuick66455 Well-Known Member

    Just got off the phone with TA about the single plain manifold still lot's of testing to do but hopefully will be in production in the spring of 2015...
  8. Mart

    Mart Gold level member

    I see Crower has this BIG BOY Level 5 solid cam discounted to $32.20
  9. alec296

    alec296 i need another buick

    I wonder if they can get some out for raceday :pray:
  10. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    You would need delivery about a week before race day so you wouldn't have to be changing an intake the day of the race, that would give you a few days to tune it as well. But yeah I know what you meant.

  11. alec296

    alec296 i need another buick

    I would like to see how Steve's new setup runs. I think it will be a good combo.
  12. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    His current combo isn't to bad either, Steve knows what he's doing the new setup should be good as well. He needs to keep that detonation in check with those hypereutectic pistons he has, Steve is that why you want to do the cam swap?

    Steve, are you doing any head porting on the '72 heads? If you are I can bring your head sections back if you want, let me know? I have the ones from Mart as well, I can bring all of them back to you for if when you want to do some porting. If you had a flow bench I would even bring another set of heads for you to do. LOL

  13. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Crower is discontinuing some of the poor selling cams. They already blew out the level 1 cams.

    I've not had an issue with detonation. Just got a nice bump with the level 3 from the level 2 with no drawbacks that I want to push the limits and see if the level 4 will function with iron manifolds. I will "blend" the seats a little when the larger valves are installed.

    Already thinking beyond this step to the next change. That will include spreading the valve center line apart and putting in much bigger valves.
  14. alec296

    alec296 i need another buick

    Hyperutectic pistons in the 350 not as bad as 455 due to size/weight . they should be OK. Similar idea on valves as derek. He is doing the same on my 350 valves.
  15. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    This is what I did with Andy's heads. Only went .030" on the intake and went I think .040" on the ex., I also pushed them both .050" closer to the spark plug which is closer to the center line.(I would need to consult my notes for the exact measurements)

    If you aren't moving the valves closer to the center line of the bore you really don't have to spread the valves out much to get bigger valves to fit. If I remember correctly I think the factory valve spacing is 1.812" apart.

    1.600"/2 = .800"

    2.02"/2 = 1.010"

    1.010" + .800" = 1.810"

    If you only went .010" for each valve you should be good with a 1.830" valve spacing, it would give you a whole .022" in between the valves. Not moving the valves closer to the center line and spreading them out further would shroud the valves, even installing the larger stage 1 valves causes shrouding. Unshrouding the chambers when installing even the stage 1 size valve should be done to the chambers to take advantage of the larger valves.

    Anyway if you go with 1.940" intake valves and 1.550" ex. valves you shouldn't have to move the valves at all and all the stock valve train will still work. You could actually get away with moving them closer together .020" to .030" each and still stuff the 1.940" and 1.550" valves in there. If you don't move the valves you'll just have to make sure you unshroud the chambers to take advantage of the larger valves. Going to large with the valves on a sbb 350 head a without moving closer to the center line of the bore may not allow enough unshrouding to take advantage of the larger size valves because to much material would need to be removed in between the chambers and make that sealing area to thin and then the flow would then just crash on the deck because the bore is to small. With Andy's engine it will be .103" over bored which will give it .0515" per side of unshrouding just from the over bore.

    With the numbers above I showed you how to calculate the space in between the valves you can play with different valve sizes and locations to optimize how you want to move your valves for the best un-ported flow if these heads are for stock class racing, can even move one valve more than the other if you wanted. For a .030" over bore I think that's what you said you have you would be better off moving the valves closer to each other and closer to the spark plug for maximum unshrouding with the 1.940" and 1.550" valves or move them .015" each closer to each other for 2.00" int. and 1.550" valves. You could probably notch the front of the shafts and shim the back side of the rocker shafts and slot the holes to push them forward?

    Can use this link to figure out the hypotenuse(the longer side of a triangle for those who didn't know or forgot) of the angle if you move both ways;

    That is the trig calculator I used to figure out how I wanted to move the valves for Andy's heads.

    With a 3/8" valve hole and going with a 1/2" bronze guide the hypotenuse can only be moved .0625" for 100% cleanup of the hole when moving both ways for drilling and reaming the .500" hole.

    Using a valve with a smaller stem will help lighten up the valve train as well seeing how you'll need to install guides if you move the valves. I will have access to a lathe when the weather gets better if you think you might be interested in some nascar take out 6mm int. and 7mm ex. titanium valves altered to work in your app. if you can get away with using those in the stock class?

    Here's a link for an example of guide Andy's heads will get;

    I prefer the shouldered guides for such a conversion because there is zero chance of them ending up in the cylinder.

    If you have any questions and still have my phone number feel free to call me. If you don't have my number Shoot me an email or PM and I'll send it to you. GL

  16. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Double check the valve spacing the 1.812" number was from my CRS memory it might be where its now at on Andy's heads, need to check notes to be sure? Might be 1.760"? I will venture out into the frozen snow stacked tundra of the back door later to the garage to retrieve my notes and post the correct numbers.

  17. lostGS

    lostGS Well-Known Member

  18. alec296

    alec296 i need another buick

    Level 5 looks to be more strip than street. Will need everything to be max effort for that to work.
  19. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Plus adjustable push rods or adjustable rockers to be able to set the valve lash.

  20. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Hey Steve, I ventured out in the virgin snow from the back door out to the garage and found my notes and the factory valve spacing I measured with the digital readout on my Bridgeport is 1.767" to 1.770".

    With 1.940" intake and a 1.550" ex. valve to have a zero gap between the 2 would be 1.745" valve spacing. So with those valves you can get away with moving the int. .020" closer to the ex. and leave the ex. where it is to unshroud the intake and still be .002" to .005" away from each other. And moving them closer to the center of the bore(closer to the spark plug hole) is another trick you can do to unshroud the valves while increasing their diameter and maximizing un-ported flow.

    I have a theory on the '73 and newer castings that one of the changes were the valves might of been moved farther apart to help keep them from cracking there in between each other? I have a set of '77 heads stored in a car in the backyard when the weather is more cooperative(or sooner if inquiring minds absolutely need to know) I plan on measuring the valve spacing to see if that might be true.

    Question for you Steve, what machining process do you plan on using to move the valve locations on your heads? Because you just can't move the drill off center and drill a larger hole and expect the hole to be straight. Not many engine machine shops have the capability or know how to do something like that, are you moving the valves yourself or do you have a shop that can do that for you?(if not I know a guy, lol)

    Sorry if I over shared on your thread, there wasn't much to read here and its still really cold and snowy here I was a little bored so I thought I would do a little writing if that's ok with you, if not I can delete these if you want me too.


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