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Well since im building a big block to stick in my car so im going to disagree on this!
Really theres not much difference in weight. If you replace the iron heads and manifold on big block with aluminium parts your find it weights pretty much the same as the small block with iron heads.
Nige, does this mean your big block had all iron parts? Since i can believe that would screw the handling somewhat
If you look at it from a cost point of view big block parts are more expensive generally but its easier to make power and reliability with a larger motor.
As far as i am aware a stock small block is good for 6-700 hp however trying to achieve that without forced induction isnt cheap or easy because of airflow and rpm limits. However its a piece of cake to achieve this on a stock big block and they will handle 8-900 hp, so i hear.
So you may well get big block performance from a small block but its not going to be cheap and probably be entirely aftermarket solution, dont forget improvements have been made in the big block field as well. Some magazine build managed 911 hp from a stock big block with no power adders
Motor i have is a 454 mark iv 4 bolt mains rescued from an RV, have it on a test rig all fired up a treat. Aiming for around 700 hp with a nice set of cnc dart heads and dual aftermarket efis.
Just cant wait till its all built up and i start it, going to make my teeth rattle
Il stick some pics on here if peeps are interested?
This could turn into an interesting debate
. As I said above, I've had big blocks before & wouldn't entertain going back to one again. Obviously, it's horses for courses & as Topcat said, if you're looking for all out power on the drag strip, then yes you could quite easily wring out more power to around the 7-800 hp mark. However, most cars don't live on a drag strip & will be used on the roads. I had a 468 cu in motor in my '55 Chevy & yes it did have iron heads. It was putting out somewhere in the region of 660 hp or so. That car ran 10.57 sec @ 135 mph without nitrous & was fully street legal. However, the thing would only return single figue mpg. I took it out on a run with the family, & did 30 mile round trip & used 16 gallons of fuel!!!
As to weight difference I have to disagree, a big bock weighs in at around 685 lbs & a small block is 575 lbs, give or take a spit. You say you can fit ali heads to the big block to save weight,...well you can do that to a small block too, as well as adding an ali water pump, flywheel, mini starter etc etc. If you fit ali heads to a big block you save 70lbs. Do the same to the small block & you'll save 50 lbs. The big block still comes in at a whopping 615lbs but the little 'un is now 525 lbs. If you're using your car on the road, you have to lug that weight around, so not only does it affect your fuel consumption, but the handling in lateral cornering. Added to that, the whole support system for the big block has to be bigger/stronger, which also adds weight. Add to this the extra cost to build a big block & to me it's a bit of a no brainer. Luckily I had a flip front on the '55, so engine access was easy, but on some big block cars you can't get to a lot of the parts easily because of the restricted engine bay room due to the sheer size of the motor. Having owned & driven a big block 10 second street car on the road, I can honestly say it was a pain in the arse. Great in a straight line but useless for anything else.
I'm now running a very strong small block in my '69. There's been some weight loss with this car & weighs in at 3250 lbs down from 3765 lbs as stock. It has been set up to handle extremely well & does so with ease. With a bigger, heavier engine, it'd be trying to push the front end out in hard cornering & wouldn't be so controlable. I know you're aiming for around 700 hp, but to be honest, unless you're only going to use the car very occasionally, you'll probably soon tire of it. The fuel costs & driveability will make going out hard work. Realistically, anything around the 500hp mark is more than adequate for
regular street use, even then it can be a bit too much (can't believe I just said that
) In the dry my car can break traction in every gear if I nail it hard. In the wet you have to be sooo careful not to be abusive with the throttle as it will put you sideways without any hesitation. As I said in another post, in the damp, at 2-2500 rpm in fourth it will easily break loose when the throttle is stabbed. It has way too much power for road use as it can't be used to it's full potential. Anything more would just be a total waste IMHO.
500 hp is easily achievable in a small block, won't break the bank & will scare most people rigid if abused, yet it's light enough to handle in the corners too. Job done in my book
I understand you've a big block & want to build that, which is fine, but I wouldn't want another one
.
cheers...Nige
Ps please post up your pics & keep us informed on how things go
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