My 350 Build

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

  1. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    OK the only real measurement I'm missing with the heads. Which will not be accurate until I get the heads milled because at the very least I'm going to get them 020. Sean seems like your not a fan of the 284? I would love to use the ta 290 if possible.. should I get the heads milled before I get the cam to make sure of comp ratio? When the heads are milled what do I use for gasket size on the calc? If I milled the heads 050 would the gasket size be measure as -10? Also I'm not against using adjustable push rods I just preferred to use stock I don't mind using if I must to get what I want.
     
  2. LARRY70GS

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

    No, when you use a thinner gasket, the cc's lost is figured by using the head gasket bore size. When you mill the heads, it comes off the chamber. Brian, if you actually loaded the numbers into a compression ratio calculator, you would see there is a difference. Using 3.840 bore, 3.85 stroke, .090 in the hole, a .040 gasket, and the 58cc chamber, and a 10cc dish you get 8.88:1. If you use a .020 gasket, you get 9.21:1. If you use the .040 gasket, and get the head cc's down to 55, you get 9.14:1. I don't know how many cc's you lose when you mill the 350 head. Maybe someone knows. I would not assume that your heads are 58cc to begin with, and that they will be 55 when you mill them .020. I would measure them.

    I also think not using adjustable push rods to adjust the valve train is not a good idea. They aren't that expensive, and it is good practice anytime you change a cam. You can also just buy one and figure out if you need a different length, then order the correct ones. Just my opinion.
     
  3. alec296

    alec296 i need another buick

    if the machine shop would have got you higher compression pistons then you could use the 290 cam . put in the 290 cam and get a turbo or supercharger from XS performance
     
  4. ceas350

    ceas350 "THE BURNER"

    I see the need for a custom ground cam in your setup, because you have yet to match the specs of the cams you want. Custom grind will give you what you need. Low end tq/HP, a nice lope at idle, ability to run as much timing without detonating, and so on I vote for custom...
    Do it right the first time.
     
  5. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    When I calculated the compression I did 55 cc for combustion chamber and 020 for the gasket to get 9.4. It was said rapporteur milling the heads 020 and using 040 gaskets would be about the same as a 020 gasket without milling.that's why I calculated it that way. But what's need to do is mill the heads and then measure the cc to find the comp ratio and enter an 040 gasket correct? Should I mill the heads before I choose a cam
     
  6. LARRY70GS

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

    Yes, mill them first, measure the cc's, then figure the compression ratio with the gasket you are going to use. Is there a .020 gasket available for the SBB? If so, use it. I get 9.5:1 with a 55cc chamber and .020 gasket. Then choose a cam, and figure out the Dynamic compression. If it is between 7.5 and 7.9, you are better off.
     
  7. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    Well just an update i measured the piston dish myself and it took 20 ccs of fluid!! Im very upset with the machine shop and they wont be getting my buisness again. I asked them to get the engine to where it would be 9.5:1 like stock. This puts me at a horrible 8:1 compression with 58cc heads. Now im at a loss on what to do.. should i put my money into zeroing the block and head milling? Zeroing will bring me up to 9.46:1 and the mill the heads to get a little more compression. Or should i buy some higher compression pistons? How much shaving can i get away with before i run into problems? If i can get the heads down to 50ccs and a piston clearance of .005 that would get my compression right where i want it but i dont know if thats a safe thing to do.
     
    Last edited: Jul 16, 2013
  8. alec296

    alec296 i need another buick

    get the correct pistons, just pull rods and have pistons replaced then put pistons n rods back in. vavle clearance really should be checked for most new combos and depends on pistons gaskets and rockers/cam. you might be able to find pistons with valve reliefs then you should be better off. but you compression will be good for turbos. I don't see the point of wasting money on taking the engine apart to machine deck more when you should just get the pistons you need much less work . and you know intake and heads will always fit well if any other work is done later check with sean as some 3.0 v6 pistons work as hi comp pistons in the 350 jim bureck did that a lot also check the machine shop am&p mike and get you some nice pistons as he has built several 350s for guys on the board I think there is a link in one of the stickys at top of forum to his buick 350 build.
     
  9. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Define correct pistons?

    If they have the designed pin height they will still sit way down the bore and not achieve the advertised compression ratio.
    The Speed Pro hyperutetics are about the only off the shelf pistons for the 350 and they will still be way down the cylinder like what you have now. They come with valve notches that may be needed.

    Your options now are;
    #1 order custom pistons with a lower pin height for $800-$1000

    #2 Cut the block to get the pistons you have to zero deck as I've said all along. Cost about $125


    Keep in mind the pistons they used are probably cheap cast pistons so you won't want to rev it much past 5200 RPM assuming they properly balanced the rotating parts. But the available intakes choke the engine at about 5400 anyway.
    With that 284 cam you won't make much power below 3000 and won't be able to rev past 5200. So your power range will be 3000-5200. With a close ratio 6 speed trans and 4:56 gears in the rear it should be pretty quick. Just hope your manual brakes will be able to stop the car because this cam won't make enough vacuum to work power brakes.

    Hope everyone gets the sarcasim intended. Not meaning to bash anyone just want people to remember all the parts HAVE to work together.
     
  10. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    What are my options for higher compression pistons that are .040? ide rather get pistons then shave everything down to where i need it for 10.5:1.. leaving these pistons and just shaving everything down seems like the easy way out.. not the right way..
     
  11. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    As far as I know you would need to buy custom pistons to do what you want. They will cost you $800 to $1000.

    ANY off the shelf Buick 350 piston will have the same pin height dimension by design. That will place it down the bore the same as what you have now.

    You would need to custom order the pistons with the pin height dimension changed a similar amount to the distance the pistons you have are down the hole. Or keep what you have and cut the block.
    When Buick built these engines they allowed extra material for multiple rebuilds that would include cutting the deck to provide a flat sealing surface. That's why the pistons sit down the bore like they do.
     
  12. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    Im not trying to raise them higher in the block though just get rid of the big dish, I still plan on milling the block and heads a little but. Even with the 10cc I originally thought they were I was going to shave a little bit..
     
  13. LARRY70GS

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

    Your best option is to simply have the block machined for 0 deck. Even with the 20cc dish, and .040 head gasket you are at 9.5:1 with a 58cc chamber, 9.84:1 with a 55cc chamber.
     
  14. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    how low cc can i get the head chamber? at 50 ccs it will put me over 10:1 and i can use that cam i originally wanted.
     
  15. alec296

    alec296 i need another buick

    mike at automachperf.com he has built several 350s can give you the rite info. he also has a post/sticky at top of page for diamond pistons. customs so like 800 but built right forged and not a lower pin height. - all specs where posted in sticky. also look up 496P pistons flat tops from a 3.0 no dish

    ---------- Post added at 02:39 PM ---------- Previous post was at 02:27 PM ----------

    look up powerblocktv.com they recently did a buick 350 with 300 hp episode was building the other 350 . also why are you set on a 10.5 comp engine- kinda high for street gas as far as cam go up to the 310 with around 9.5-10 to 1 should be strong
     
  16. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    I want to put the TA_290 cam in the engine it has the performance and sound im looking for. 10.5 is what is needed for that cam to run correctly, My only option for higher compression pistons at 040 is custom ones? i find that hard to believe..
     
  17. ceas350

    ceas350 "THE BURNER"

    Try flatlanderracing.com
     
  18. alec296

    alec296 i need another buick

    do you know someone running the 290 or are you just going by what is advertised. did you look into other pistons ? hyperutectic,silvolite,federal mogul,trw falcon on ebay has hi com pistons ta has cast hi comp pistons . call and get specs from these pistons. and yes 10.5 comp is not standard so it will be a make work set up or customs. your already having to take engine apart cause your guessing at parts. call mike at am&p he has built many buick 350s he will have the rite combo you are looking for. he has used the 310 cam many times for A 350 HP 400 torque buick 350 look at his site call . he has the experience you need to get it done. if not call tapeformance and speak to tech about cam and pistons. get the answers from the people that use the parts.
    also check with sean on specs for the 496p 3.0 pistons he mite even have some pistons left
     
  19. Brian350skylark

    Brian350skylark Guzzling Gas & Haulin Ass

    Yeah I have looked some island have found a couple. There are a couple combos I have found online with this cam. I called ta performance about this cam and they said as long as I replace the springs I'll be fine with 9.5:1 comression and the rest of my setup. Larry and Sean both agree that need over 10:1 for this cam to run how it should
     
    Last edited: Jul 17, 2013
  20. jay3000

    jay3000 RIP 1-16-21

    What kind of final combo are you looking to run??

    gears, convertor, tires etc.. The whole combo has to be right.
     

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