small block vs. big block in a cobra

[Anthony]

Originally Posted by boyd henderson

trying to decide small block or big block? --any happy big blocks drivers

I don;t know of one.

Originally Posted by boyd henderson

thanks for all the input ,i guess i will be happy with either.you cant make a bad choice

You can make a bad choice on who builds you the motor.

[gjcomb]

I agree with Silverback51 - I am also owner of a big block in my machine. But with a big block come some problems (like heat) and advantages (lotsa torque).

You have to make a decision on what you are going to do with the car and go from there.

[bret a ewing]

We still on this?


FIA & Slabside = SB.

427 - Street or S/C style = BB.

The end.

[bbsnake]

Originally Posted by Tom Wells

My tag line gives perspective...
__________________
Wells's law of engine size: If it matters what gear you're in, the engine's too small!

Yessir, that would be the correct perspective

[ByronRACE]

As far as heat and a big block goes, I can't get mine to run hot enough, and the block is 1/3 filled and the engine is supercharged...so if you're having trouble in that regard I think you have a cooling system deficiency or tune problem. I spent hours on the dyno last saturday with no supplemental cooling fan and a ton of run time and the hottest it ever got was 167deg F.

As far as happy...I'm very happy with my choice. Durable. Makes tremendous power with ease on pump gas even with a very soft tune and low rpm. 600/600 to the tires at 5000rpm having not reached a torque peak yet. If I had to guess, I'll have a torque somewhere around 5500 and peak power somewhere up around 7000...power to burn. And, this is with 16deg total advance and an 11:1 AFR on a 7.8:1 compression supercharged tiny 435" big block pump gas build.

I can only imagine what it's going to make at 12:1 AFR and 24deg advance...which I'll know this Saturday if my fuel injectors arrive. Probably near 700ft-lbs and over 800hp to the tires on pump gas. That looks like a good guess at this point.

The great part is...this is being done with an OEM block and OEM crank, OEM fuel injection, and a 429 based build and a relatively small supercharger (Vortech V7-JT). Just imagine what you could do with a 545" build on a race block with a huge blower. The big valves and big ports of the 385 makes power so much more easily than on a small block platform unless you start looking at exotic parts. It's amazing how much you can do with this platform on a budget. I have less than 8K into my engine; including the EFI and Supercharger.

You'd spend a hell of a lot more to try to duplicate the output on a small block platform. You'd have to start with a race block and a billet crank, then top it with some exotic heads. By that point, you've already come near the price tag of my completed engine assembly. Power per dollar, the 385 is a pretty amazing platform.

That said, I've found that more than 500rwhp in a Cobra is pretty ridiculous; that's near the traction limit starting at freeway speeds. If you have no experience behind the wheel of low-tech cars with big power, I wouldn't recommend more than 400rwhp for the first time out; that's enough to scare most anyone. Mine is basically a half-throttle street car; WOT is reserved for straight line track duty.

B

[mcwho]

Has anyone found the stats on Carroll Shelby's Cobra wins.

How many races were won by small block Cobras vs Big Block Cobras.

Over the years I have read somewhere that most of the early races were won using the small block Cobras. And the Cobras with the V=Big Blocks were heavily modified as I understand.

Anyone have the REAL Numbers ???

[KevinW]

so are as i am aware, it was the small block cars that won at international events. But these were virtually all Ace/289 type bodies.

Happy to be corrected.

[cycleguy55]

Originally Posted by mcwho

Has anyone found the stats on Carroll Shelby's Cobra wins.

How many races were won by small block Cobras vs Big Block Cobras.

Over the years I have read somewhere that most of the early races were won using the small block Cobras. And the Cobras with the V=Big Blocks were heavily modified as I understand.

Anyone have the REAL Numbers ???

I believe you're correct in that most Cobra victories came with small-block cars, but it wasn't that the big-block cars weren't as good as the small-block cars - the racing landscape changed as well

[MKS427]

Carroll Shelby originally wanted the aluminum 390 FE for the S/C. NASCAR would not give them up. That said, he was probably looking for to keep the car balanced and get as much power as possible.
If your Classic Roadster has a 96 inch, wheelbase it would throw off the weight bias relative to a 90 inch wheelbase car. In which case you might want to consider a lighter power plant, if you desire better handling.
I was considering a big block, but only if I could get a hold of one of the aluminum Ford blocks that are no longer in production. I ended up going with an iron Dart block stroked to 427. I built it to have better low-end torque numbers versus high-end horsepower. I am very happy with it.
Whatever you decide I am sure you will enjoy. Probably the best recommendation, is just to make sure it will be reliable on pump gas.

[mdross1]

Big block versus small block will always be an individual choice mine was big block for reasons I'm sure a few do not get. What ever the power plant choice for your ride make it all it can be it will pay in the end. Having cars like these should bring out that inner desire for wanting one every time you walk by it. For me part of it is lifting the hood and seeing the engine bay full of big inch iron capable of putting a smile on my face that won't go away.

What other reasons would someone want one of these cars,racing them is certainly a thrill some enjoy I did a while back. These days a spirited row through the gears, passing, or giving someone a white knuckle ride sure ramps up the fun factor. No matter we cannot live this life over so why do it with regrets. Install the engine of choice climb behind the wheel and have the kind of fun these cars are capable of dishing out.

Mike

[Ace23]

Originally Posted by ByronRACE

As far as heat and a big block goes, I can't get mine to run hot enough, and the block is 1/3 filled and the engine is supercharged...so if you're having trouble in that regard I think you have a cooling system deficiency or tune problem. I spent hours on the dyno last saturday with no supplemental cooling fan and a ton of run time and the hottest it ever got was 167deg F.

As far as happy...I'm very happy with my choice. Durable. Makes tremendous power with ease on pump gas even with a very soft tune and low rpm. 600/600 to the tires at 5000rpm having not reached a torque peak yet. If I had to guess, I'll have a torque somewhere around 5500 and peak power somewhere up around 7000...power to burn. And, this is with 16deg total advance and an 11:1 AFR on a 7.8:1 compression supercharged tiny 435" big block pump gas build.

I can only imagine what it's going to make at 12:1 AFR and 24deg advance...which I'll know this Saturday if my fuel injectors arrive. Probably near 700ft-lbs and over 800hp to the tires on pump gas. That looks like a good guess at this point.

The great part is...this is being done with an OEM block and OEM crank, OEM fuel injection, and a 429 based build and a relatively small supercharger (Vortech V7-JT). Just imagine what you could do with a 545" build on a race block with a huge blower. The big valves and big ports of the 385 makes power so much more easily than on a small block platform unless you start looking at exotic parts. It's amazing how much you can do with this platform on a budget. I have less than 8K into my engine; including the EFI and Supercharger.

You'd spend a hell of a lot more to try to duplicate the output on a small block platform. You'd have to start with a race block and a billet crank, then top it with some exotic heads. By that point, you've already come near the price tag of my completed engine assembly. Power per dollar, the 385 is a pretty amazing platform.

That said, I've found that more than 500rwhp in a Cobra is pretty ridiculous; that's near the traction limit starting at freeway speeds. If you have no experience behind the wheel of low-tech cars with big power, I wouldn't recommend more than 400rwhp for the first time out; that's enough to scare most anyone. Mine is basically a half-throttle street car; WOT is reserved for straight line track duty.

B

That sounds WICKED! Good luck with the remainder of your tune and let us know how it turns out.