|10-25-2012 09:07 PM|
|matt406||well i have a machinist that will sell me a set of 906 vortec heads fully ported and polish with 2.02 &1.60 valves with screw in studes guid plates .550 lift springs for 600.00 out the door with no core charge. he said i wont need the vortec roller rockers with the guid plates. im wanting peak torque at 3900 rpm.i think dart heads are twice that.|
|10-25-2012 05:54 AM|
cheap as dirt at a junk yard.. same with the vortec rockers if you are going to compair him reuse'n the ones he has over buying new..
the intake, yup.. got to be vortec style.. but I'm willing to bet the edel heads cost more than the vortecs AND the intake compined...
not to many people buy'n new heads and reuse'n the old rockers and pushrods,, kinda a moot point.. same with the dirt cheap valvecovers
|10-25-2012 05:03 AM|
vortecs also require the use for vortec rockers, vortec valve covers, and a vortec intake. So, the price goes up if you already have these parts for a non-vortec head.
I would get a set of edelbrock performer heads or maybe a set of dart iron eagles. The vortecs are good but consider all the extra money you will spend to use them.
|10-24-2012 10:50 PM|
|idontdrivericeieatit||I read a lot of stuff bout the vortec from alot of places and they all say 2.02 vavles dont help stay with 1.94 just go to 1.60 on exhaust vavle but before I would spend all that money on vortec heads I would buy a aftermarket set of heads that are alot better vortec are not a real good head unless u talking stock stuff they better than most stock gm heads but thats not saying much by time you buy the head port polish have spring pocket clearence for a real spring. Buy all new springs and vavles Do screw in studs u could buy set of dart heads or some other aftermarket head that will outflow them and make more power|
|10-24-2012 09:54 PM|
|vinniekq2||build the heads,get them ported and flow tested.2.02 valves may not be required,,,when you have flow numbers you can piece the rest together. pre determine what you want for fuel economy first though???|
|10-24-2012 09:36 PM|
|matt406||i was thinking vortec heads ported polished 2.02 1.60 valves stainless valves screw in studes and guid plates and a holley carb|
|10-23-2012 09:42 PM|
|vinniekq2||for fuel economy and performance,start with the heads and fuel management|
|10-23-2012 09:24 PM|
|matt406||well i have a virgin 509 blockn thats been maged and hot tanked got it for a 100 dollars. got a new eagle crankshft for 130.00 and scat procomp rods 6" for 195.00 . i dont have really have the cash for a big block. it is going to be a daily driver. so fuel milge and performance will be in consideration.|
|10-23-2012 08:25 AM|
|10-23-2012 05:24 AM|
My truck has a 3.08 gear. I can drive it to work and not go over 2000 rpms. Yet it still gets 8 mpg. The sbc in the same situation gets around 11 or 12. Seems like enough gearing to me.
It's no mystery that a BBC is not an efficient engine. I'm just letting the original poster know that BBCs are thirsty. However, since it is not a daily driver it will not matter that much.
|10-22-2012 06:50 AM|
to get good mpg out of a big block you have to gear to use the low end..
I had a mid 80's monte ls with 2.14 reargears and got 17 city and 29 highway.. with a vac 2nd carb.. efi , so I'm told would even do better.
|10-22-2012 06:00 AM|
396BBC vs 400 sbc
|10-22-2012 05:38 AM|
Well, I have ran BBC and SBC in the same truck with the same drive line and I promise you a BBC gets a lot worst MPG than a SBC.
Very inefficient heads and more internal losses makes the BBC a gas hog, plain and simple.
|10-21-2012 08:01 PM|
|matt406||ok the old man is right . but i still like the 400 sbc more especially with the new big stroker assembellys available today. thank you for your info.|
|10-21-2012 01:18 PM|
If you compare SFC based on fuel burnt per horse power produced,you will find that there is very little difference between small and big blocks.You cannot directly compare a 350 hp 350 to a 350 hp 454.MPG is dependent on gearing and other factors.A 454 that makes the same horse power as a 350 will make more torque,there fore to compare MPG the 454 can use a taller gear because of the higher torque output so should be operated at a lower rpm for fuel economy.Both engine convert the same fuel to heat,,,, If you get down to the technical differences then the BB will lose some efficiency due to the heavier crank and reciprocating weight,slightly more friction because of bore,extra few horses required to move the extra 100 pounds.
again horse power is a part of the power formula,torque is also a part to consider.High performance engines require similar pounds of fuel to create similar power outputs.If you compared a 700 hp 350 to a 900 hp 454,the pounds of fuel burnt per horse power create would be very close.
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