Crimson Thunder

Since you already have a big block, I would vote to purchase some nice aluminum heads for it. Buy some nice small port(that flow very well) heads and use the cam you already have. The aluminum heads will take some weight off the front of the car.

roscobbc

What he said /|\. OP has the advantage of already having the BB engine - love it - exploit it - for street use you want torque and as much as you can get over as wide a rev range as possible - don't concern yourself about handling - you already have a vehicle that with a little attention and some modern rubber will run rings around most other comparable cars from the same period on the street - and happy Xmas to all on here.

derekderek

To OP.You have a 454? Or you have a corvette with a 454 in it? My 75 has a 350 in it. I have 2 454 and a 502. But no brackets, exhaust (non-marine anyway), etc. So the 75 is staying 350 for now. If that BBC is mounted in that car and running, YOU have no brackets, exhaust, etc to run that small block. Do the math. Stay with the bigger, more powerful, cooler, rarer, BETTER setup...or ship ME all your big block brackets, etc and I'll ship you all my common, worthless small block brackets. Happily... Oh, and in middle of last page somebody said a big block outweighs an LS by 500 lbs. BBC weighs 700. LS weighs 200?

ajrothm

Since you already have a decent built 454, absolutely no reason not to use it. The ONLY downside to it is if you don't have the pulleys/brackets.... If you have to buy all that stuff new, it gets pretty pricey...(I did it)...

Nothing like popping the hood and seeing a rat motor in a vette...

Now if you are thinking about road coursing (track days) the car, then a small block is probably a better way to go.... But for normal driving/cruising and street brawling, can't go wrong with a built 454...

OldCarBum

It is stated time and again on the forum. It's your car, do what ever you want.
I'll always say, do your research, then do some more.
In this case I would fine someone near you with a sbc in a similar year, model corvette, and drive it.
I believe you will instantly see that you would miss the big block in your corvette.
When I was looking at purchasing a corvette, I test drove several sbc's.
Once I drove the big block, I was convinced, big block only for me.
Throw on a set of aluminum heads and a 496 stroker kit, with a good mid range cam, and go.

mrichi

I've had a high performance SB but now have a 454 BB which puts out 450HP.

As for everyday driving i think the BB is far better ,it's the low end torque that a big block puts out which makes everyday driving so much fun

69Vett

first question out of everyone's mouth, ... is it a Big Block ?
build the BB keep the block, put all new everything else add HP inside it.
with crank rods and new pistons.
not to mention you keep you original numbers matching BB.
Do Not let them deck your block and remove numbers.

bence13_33

Pretty sure the BBC 294S has 248 @ .050" and .595/.595 it's a single pattern and a pretty fun little cam.

I think the weight issue of the big block is being blown a little out of proportion here (pun not intended). If you are that worried about the weight, slap a set of aluminum heads on it and you just shaved 80lbs off the front end and are within spitting distance of a the weight of a cast iron small block. I still have the stock L48 springs in my car and ran it like that with the big block and iron heads. Obviously in a maximum effort road race/autocross course type situation a nicely built small block is likely the way to go. If it were me I would build up the motor you already have, it's a much more cost effective route to go.

Taijutsu

I remember back in the day when AX was about the only thing other than drag racing. A BB Vette was not very agile on the tight course and made a mess. lol

I'm guessing this is where the reputation for poor handling got started?
Back then the hot set up was to have a Jag rear end put in, I can't remember why?

Dropping a #100 lbs off the front of a Vette has to be a good thing be it a BB or a SB.

JMHO

R

CA-Legal-Vette

I've seen a range of numbers quoted for weights of BBC and SBC engines. Found this table that was interesting in that it includes a lot of other motors too:

http://www.team.net/sol/tech/engine.html

The consensus is that an iron headed SBC weighs around 575 pounds and an iron intake and headed BBC weighs around 775 pounds. The BBC weights seem to range more than the SBC ones. A set of BBC iron heads weigh around 160 pounds vs 45 pounds for a pair of aluminum ones. The iron intake weighs 65 pounds. I'm guessing the aluminum intake weighs 15. That would mean that an aluminum headed BBC would be 35 pounds more than an iron headed SBC.

I wouldn't consider switching to a small block for that difference.

YRMV.

OldCarBum

So what weighs more, 20 gallons of unleaded fuel in the fuel tank or 20 gallons of leaded fuel in the fuel tank?
If the leaded fuel weighs more, could running leaded fuel in a big block, balance out the front to rear weight ratios for the big block making it an overall better track car?
Yes, I'm being a smart a$$.

roscobbc

2 x 45lbs per ally head = 90lbs. 685lbs for iron headed BB engine.

Taijutsu

looking at the list I see a SB weighing #575 and a BB is #685. That is #110 by my math. That fits w/the info of a BB weighing about #100 more than a SB.
Not sure where the #775 came from?
Both can lose #100 lbs w/money!

Something about the off idle grunt of a BB is very appealing.
Compared to a 350 SB, I'm sure a 400 SB has more everywhere!

Jebbysan

If you have the 454....use it. If you want to build a small block, do not mess around with a 383.......go 406 or larger......
The only reason to build a 383 IMHO is to use the factory block......they run good....but a 406,414,427 runs MUCH harder.....the bore size is what does it.
As far as handling.....if you are not autocrossing or trying to beat the Nurburgring....you will never notice the 100 pound.....

BTW.....an Aluminum head BBC comes in at just under 700 pounds.....Iron head is 775......SBC is 575 and 620 respectively.
I have personally weighed these in all forms as I had to ship what I sold/built many years ago......

Jebby

CA-Legal-Vette

I don't think they're that heavy. From the Summit website I found a couple of places where the weight is quoted. Those were 27 and 28 pounds each. Pretty close to the 45 pounds for a pair that I originally suggested.

As for the complete iron head BBC, much harder to find accurately. My 775 figure is the median weight from my search. Ranges from 675 at the bottom end to 825 at the top. 775 is the most commonly quoted weight that I could find.

Jebbysan

Fully assembled alloy BBC heads are 45 lbs. each....all day long.....Iron are 80lbs.

Jebby

The13Bats

Around 2010 my dad now rip talks me into a 383 built by his racer buddy,

Im old school i like the beastly grunt one can only get with a bb. But i let my dad talk me into the 383,

It was a mean engine that one had to turn up to get any thing out of,
I hated it,

I got lucky a member swapped me his mild 454 for my 383, he liked rpms
Money wise i lost but i really love the 454 for what i do,

I dont think the blanket answer is bb or sb but rather build what you like best in an honest way as to how you will use it,

v2racing

Myself, if I had started with a big block car, it would still be a big block. Being I bought a small block car and I had a small block I already built, it is still a small block car.

It's expensive to switch from on to the other. Stick with the big block.

Mike

OldCarBum

Add some weight for a "tall block" truck motor and I'm sure a forged crank will out weigh a cast, aluminum versus steel valve covers, also weight with a flywheel over a flex plate could be substantial.

The13Bats

While my swap trade 383 sb to 454 bb was admittedly a dream as we both had all the same options right down to hookers, so all it cost us was labor,

Back in the 90s my modded 66 had a 327 4 speed no power stuff,
I had a 454 ready to drop in that would have been labor only but a free swap,
only a guy offered too much for the 66 and i got stupid and took it,

How is the swap expensive aside from corvettes having some special bb brackets im missing why you see it as expensive, what did i miss?