I have a 383ci stroker, and I want to put a 8-71 blower on it running alcohol.All out race motor.How much more power can I expect?Will a stock chevrolet 4 bolt main block hold up?I have a 4340 forged rotating assembly.Will I have to do anything to the block?Is there a big difference from racing gas to alcohol?Whats the best transmission for it powerglide?Fuel injection or carburetor?Any advice would be greatly appreciated.Motor is putting out about 600+ raw horsepower.  

What bracket are you wanting to race in?  Are you planning on racing at all?  Research that bracket and what those rules are and what is being done by the other people that are racing in it and we can go from there.  If you just whant to build some screaming fire breathing non street leagal moonshine motor - we can do that too.  Blowers and Alcohol are cool!  Post Back           chris  

A GM block could be heavily taxed. There is no real definitive way to know exactly what kind of bore thickness you have, and I doubt you had the block sonic-checked so are completely clueless rather than just a little questionable.

The block should undoubtedly be fitted with splayed main caps - more than likely steel splayed caps.

A 4340 forged assembly doesn't really do the durability of the setup justice either. Even some of the imported cranks and rods are made with 4340 nearly 1,000 horsepower. What I mean here is Eagle, Scat, or even cheaper brands.

The big difference is supplying all that fuel to a VERY high horsepower engine. You will need A LOT of fuel pump capacity and specifically calibrated needle and seat to keep the float bowls full under WOT conditions when the engine will guzzle fuel. Actually, all alcohol engines are going to need a specific carb - another big reason is that alcohol is so much more corrosive than gasoline and requires difference components.

Fuel injection is always going to be more expensive.  It will probably also drive up the cost of a blower.

Since you will be spending a lot of money on this rig (big horsepower is always going to require a lot of money) you should be talking to a custom carb manufacturer to take a lot of the guess work out of tuning a carb for this setup. One of the reasons I say is that the standard Holley jet may be outpaced by this setup and a different jet setup may be required, also when you're dealing with multiple carbs tuning is always going to be more difficult.

It's difficult to say what the best tranny would be without knowing anything else about the vehicle. The large and widespread power a blown engine will make would do fine with only a 2-speed, as long as the stall is incredibly high of course.