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SBC heads?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MNorby, Aug 19, 2002.

  1. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    My buddies truck needs new heads. It is an 85 chevy 350 (carb). It currently has headers and an edelbrock carb. He has a weian intake on the way too. The head on it are completely shot and fried. What kind of head do we wanna look for for this truck? Any help is appreciated.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, if it weren't for the intake on the way (is it returnable??) I'd say Vortecs. New intake of course, but hey, about the best bang for the buck IMO.

    I recently heard of some Vortec "kit", but not sure what it entails or who has it (maybe www.sdpc2000.com ?)...You can get the Vortec Performer intake for $150 or so, and the heads for about $550 delievered IIRC.
     
  3. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    that was my first answer to him. According to the machine shop if he gets aluminum head we will have to deck the block and we don't wanna have to pull that. Know of a place to get good aftermarket cast heads and gain a few HP? Basically wants something ready to run
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Vortecs are cast iron. Don't know what they are talking about "decking the block", but any time you change heads on a running motor, you might have deck problems, what with not quite flat surfaces and all...but head material shouldn't matter.

    I've heard of GM dealers actually selling Vortecs pre-drilled for the "old style" intake pattern, (think it was scoggin-dickey) but from what I've heard, thats not really a good idea.

    Even Paceparts.com mentions the Vortecs are thinner than earlier castings, which is no problem in anything but extra hot running motors, but if the castings are thinner, then drilling extra holes into them probably isn't a good idea. I've seen that "don't drill the old style" holes statement enough times to believe there must be some merit to it, especially coupled with the thinner casting statement.

    Bang for buck, besides having to get a new intake (which he is doing anyway) I don't think you can beat Vortecs, especially for a truck motor.

    Low end power is where its at for most of us, and Vortecs excel at this.
     
  5. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    thnks for teh advise. Maybe I will buy teh action plus intake from him for the $70 it cost off ebay then he can get vortec stuff. I'll let him know. Thanks man!
     
  6. bigmack

    bigmack 1/2 ton status

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    I agree with dorain about the vortec heads, they are hard to beat (especially for the money). But if your friend is wanting to stay with an old style casting, some 186's or 041's from the late 60's or early 70's would be great, they both have the accessory holes in them, so that wouldn't be an issue. But they can get spendy, first you gotta find a set that someone will sell and then have them worked, and by the time your'e done you have more in them than a new set of Vortec's would have costed in the first place.
     
  7. RaisedK5

    RaisedK5 1/2 ton status

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    The Only problem with slapping on a set of vortec heads is that they have, what? a 64 cc chamber, so if you slap them on an engine that was running 8.1-8.5 with a 76cc chamber, compressions gonna get high pretty quick, if thats cool with you then go for it. Or do something like i did, i have a pair of world products SR Torquers, and am really happy with them , you can find them in ads in the hod rod or super chevy for around $650 i think, or order a pair from summit for around $750, all brand new, 2.02, 1.60 valves, all the accessory holes, etc. and they come in a 76cc and a 67cc depending on if you want to bump compression or not and will accept that weiand intake. Just an idea /forums/images/icons/smile.gif
     
  8. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    hmmm. What CC should we go for? This is basically a stock motor. Do vortec heads need centerbolt valve covers? Basically looking for something to bolt on and make it run on all * (had burnt exhaust on old heads and ran on 7) and give it a few more ponies
     
  9. RaisedK5

    RaisedK5 1/2 ton status

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    If it was me, i'd stick to the 76-72cc range, i think the world Sportsmans have a 72 and come in iron as well and are not too costly, since its a truck and will see some abuse and im sure you probably dont want to run premium in it i'd stick to something right around the stock size chamber. Plus both of those heads offer some serious potential for a later more radical motor, a little porting here, a little shaving there, paired with the right piston and bam a pretty nice engine, thats what im planning for mine, My SR Torquers will eventually find a new home on top of a 406 Block.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Vortecs *should* raise an otherwise stock 350 to between 9:1 and 9.5:1 IIRC.

    With speed-pro hypereutectic pistons, and the 64CC Vortecs, compression is 9.2:1.

    You can easily run 9:1+ on 87 octane with good chamber design, and the Vortecs are. Stock truck 305's were 9.2:1 and ran fine on 87, which is the recommended grade for them.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Vortecs are center bolt valve covers. Centerbolt covers are a dime a dozen anymore. With their superior sealing characteristics, they too are an upgrade.
     
  12. RaisedK5

    RaisedK5 1/2 ton status

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    Hey Dorian, Not to jump off the topic, but aren't the piston designs on the vortecs better too? , better quench, and all that stuff, would that make a difference on how they perform on a non vortec engine? I heard that the vortecs ran high Comp ratios, i figured it was due to the chamber and piston design, that might be a little different than the older engines, What do you think??To be totally honest i have the 67cc chamber S/Rs on my truck, with all else being stock, and it runs just fine, and i don't think i've ever heard it ping, and the vortecs are great heads, i was just saying a more conventional head with a bigger chamber so that he doesn't get suprised by anything and all the other original parts would bolt on. /forums/images/icons/cool.gif
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    I just did a cursory search online, and couldn't find any info on Vortec motor piston design.

    I doubt the Vortec pistons have any differences than any other basic flat top or dished piston, if I remember correctly, a flat top piston is (at this point in time) optimum for combustion efficiency, with the cylinder head design being where changes should be made. Flame front and propagation are the problems you run into when you start messing with the piston design,(such as domes, or anything that blocks flame travel or disturbs airflow) but in some cases, to achieve a lot of compression, you don't have much choice.

    It's my understanding that the Vortecs are so good because GM A)did an extremely good job casting them (my casting ARE smooth) B) the combustion chamber is awesome and C) the ports are also well designed. I'd imagine at this point in time, GM has figured out how to get higher compression, better, cleaner burn, and whatever flow characteristics (swirl, etc) necessary to make power, all in one set of heads, whereas in the 80's, it was all about restrictive ports that promoted velocity and swirl solely, with outdated combustion chamber design.

    Since these are 64 CC heads, the Vortec swap is really no different compression wise than going with any other SBC 64CC head. I believe 10CC's is equal to approx. 1 point of compression in a 350, so if you are starting out with a 76CC chamber and 8-8.2:1 compression(such as a lot of 70's and 80's 350's) you should still be safe with the Vortecs, as the combustion chamber design lends itself to higher compression without detonation, which means higher octane gas isn't needed.

    Of course, if you already have 8.8:1 or something with 76CC heads, and swap 64CC heads, you'll end up having to run mid grade or premium.

    If I were doing the swap (and I am) I would make certain that the compression I was running to start with, won't exceed what I could run on 87 octane. (which I have) In my case though, I was able to verify the CR via the piston maker, since I am building the engine from scratch, whereas someone that is interested in swapping heads alone, would need to be more careful, and do some careful calculating.
     
  14. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    well, my buddy ordered aome 440 (?) heads today. The number started with a 4 anyways and I can't quite rmemeber. Now got me thinking though. I have a 400 sbc. Will the vortec heads work on that? WIll I have to drill the steam holes or whatever?
     
  15. twenty_below0

    twenty_below0 1/2 ton status

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    I agree in one since but not in another, 560.00 plus shipping for the vortec's.....plus 159.00 for the intake. This is
    around 700.00 why not by a set of Sportman's for 750.00? They are better than the Vortec's, hands down!
    Also one other question how many miles on the engine?? If it's got alot then you run the risk of blowing the rings out
    I know this from experience if it's not TIGHT then bolting a new set of heads on will cause it to start burning oil, I would
    suggest a leak down test first before I buy the heads and then start the burning oil process. Just my .02
     
  16. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    I've got 7 L31 rods and pistons laying around. Can't decide whether to use those rods or not. Anyways, the pistons look exactly same as any old plain jane 350 piston through the years. I'm not good with compression math, but wouldn't Vortecs lower compression. I think 305 heads have 58cc chambesr and I was looking at an old Blazer brochure and it had an 80's 305 rated at 9.2:1. I think I noticed that because it had something about the 305 not being available in California and then that higher compression made me think that was the reason.
     
  17. zcarczar

    zcarczar 1/2 ton status

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    If anyone was wondering the stock vortec motors have 9.4:1 comp. and run fine on 87 octane. They run really strong for a stock truck motor.
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    Can you get the Sportsmans for $750 WITH shipping?

    I know nothing about the sportsmans, but what I'd have to say is:

    Vortec heads were MADE for trucks. Most of the aftermarket heads are made for cars. They are made for light vehicles that turn a lot of RPM's, and the better flow of some aftermarket heads means that low end power is sacrificed in most cases. Bigger valves don't help either.

    "Power under the curve" means something when you are talking about daily driving a 5000LB plus vehicle.

    Of course, Vortecs can be improved upon with porting and bigger valves if you are worried about high RPM performance (mud racing I'd imagine) but if you are going to that kind of work, I'd agree with you, get heads that are more capable out of the box.
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    There are 58CC 305 Vortec heads, if thats the route you wanted to take. I'd get a 350 before I'd get Vortecs for a 305 : )

    Thanks for the L31 info, no chance that GM changed the pin height or anything is there?

    Did Chev change the piston to change compression as well as increasing combustion chamber CC's? I'm talking dished vs flat top pistons, etc. I haven't had enough Chev's apart to know what a dished Chev piston looks like vs a "flat top" and whether a "flat top" piston with 64CC heads will send compression to around 10:1 as my circle track friend says.
     
  20. zcarczar

    zcarczar 1/2 ton status

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    The vortec pistons i have setting in my garage appear to be a flat top with a little bit of a negative dish and the four valve reliefs. I dont know for sure if the non vortec engines are any different, I could find out tommorrow at work though.
     

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