" grumpy? have always wondered about equally powered bb vs small block power.i have owned quite a few of each.i would like opinions from us old knowledgeable timers.i would like opinions from anyone but really hope performance experts like grumpyvette will chime in.Question is if you would take a test car,such as a first generation camaro with its stock 396-350 horse motor and make 3 quarter mile passes,then exchange motor and replace with 327-350 horse corvette engine and make 3 runs,what would expected results be? "
Size and Weight
Aside from cost and lack of availability, the Rat's primary drawback is its sheer size and weight. In stock form, a 454 big-block tips the scales at just under 685 pounds compared to the 575 pounds of a standard small-block. You can reduce the weight of either engine by more than 100 pounds by using aluminum heads, intake and tubular headers, but such lightweight big-block parts can be prohibitively expensive. Aluminum small-block parts are relatively cheap and easily accessible, so Mouse trumps Rat for weight. The big-block is 2 to 4 inches larger than the small-block in length, about 5 inches wider and 6 inches taller.
that test has been done several times and the results tend to favor the BIG BLOCK, even thou in theory the sbc weights less the fact is that the better head flow and torque curve the big block produced usually resulted in the big block combo being faster, keep in mind either engine style can produce in the area of 1.2-1.4 horse power and foot pound of torque per cubic inch of displacement if properly configured and built,
if a 383 SBC makes 1.3hp per cubic inch thats 498hp
if a 496 BBC makes the same 1.3 hp per cubic inch thats 645hp
now if we stick the 383 in a 3500 lb car thats 7.03 lbs per horsepower
stick the big block in the same car and add 125 extra pounds you still find you get 5.62 lbs per horsepower
I get asked frequently why I build more big blocks than small blocks and its simply because I build mostly muscle car engines where durability and drive ability in a daily driver is the main goal, and where having something rather impressive to look at under the hood, and something that easily smokes the tires, is usually a big plus in a car thats a week end toy.
that extra 120 lbs the stock iron big block weights looks significant until you realize that the 120lb difference in your average 3400lb car is about a 3% change.
and remember if you use an aluminum water pump, aluminum intake manifold and heads on a big block its true weight is a lot more similar to an all iron small block,
Id also point out that up to about 450hp the small blocks generally cheaper to build and above about 600hp there little question that the big block tends to be FAR more durable, but theres a third option, the newer LS series potentially allows you to make 500plus or so hp cheaper that either of the previous engines, provided you can get a good salvage yard donor engine at a good price.
the engine you select should depend on your true goals and budget, don,t get locked into thinking you musty build a sbc, that tunnel vision can cost you, I recently assembled a 440 mopar for a guy, it was a budget build using almost all stock components, he had a goal of 400 hp, we easily made a bit more and it cost him less than $3500 to do it as he found a 1970s motor home in some guys yard,with a good 440 motor for sale that had a bad transmission and a crappy body for under $500, so he got a 440 mopar and a dana 60 rear for $500
in most cases cars are geared to maximize mileage to some extent the big block tends to have a broader torque curve that comes in at lower rpm making the gearing far more effective, its not PEAK power that counts its AVERAGE POWER. in the useable RPM BAND.
I constantly see guys who want to build a small block that will make 500hp at 7500rpm, then gear the car so the engine spends 90% of its time in the 1500-5500 power band, then they act clueless why the car acts the way it does and ask why the cars a dog.
450-500 hp plus 383 CID SBC strokers and 600-700 hp plus 496 CID BBC strokers are not all that difficult to build ,
but your average street ,muscle car engines, are much more likely to fall in the 350hp-450 hp for a sbc or 375-525 hp for a big block, power range
related threads worth reading thru carefully
http://www.chevyhiperformance.com/techa ... ewall.html
CALCULATORS TO PLAY WITH
http://www.wallaceracing.com/Calculators.htm
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