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Big Block Power

mkhammer said:
Wow a short shaft alpha not many of those around,
Head work and bigger cam would mean Higher RPM to utilize the upgrade. If you engine is fairly fresh you could use what you have for a pro charger upgrade.

You would be at about 9.2:1 with 72cc heads. With a Whipple you would have to get your compression down to about 8 to 8.5:1 or run low boost for it to live. Screw drive and roots style blowers make big torque down low with any kind of boost to them. You need to design your engine from the start to run one if you want to use all the potential of your blower.
True with a pro charger setup too but....

With a pro charger you can run a more aggressive CP ratio and get away with 9.2:1 cr. with a M1 7 psi kit. Pro chargers have a much cooler boost charge and they build boost with RPM. Aluminum heads help greatly .The cam selection is important. A grind on a 112 lobe center for the SB with high lift and not so aggressive duration would work best, ( a high lift torque profile). Ignition is important too with a pro charger you can run some curve and not much advance all in by 2400 rpm @ 24deg. the above setup lock it out and not exceed 28 deg. pro chargers are easier on drives because they build boost with RPM. Still would do a Alpha in. Synthetic gear lube helps a lot with frequent changes. with 500+ hp a bravo upgrade would be good. Since a SB doesn't have the torque a BB has you could probally make a standard bravo 1 last a long time.

MKHammer
Click to expand...

Thanks a ton for the pointers! (and sorry for hijacking the thread!).

Am running running redline shockproof in the drive. It has a 1.32 gear right now, but I'm seriously considering having it set up with a higher gear (would be faster). There's a guy locally that's well known for being "the man" on setting them up. The shorter drive and larger skeg made a huge difference in the handling - used to start to feel a little loose sometimes at much over 70, but is stable as can be into upper 70's now (current wot before some minor mods, thinking might break 80 next time out with different carb and intake and a nice 40 degree day with some light chop)...

Am currently running Tbolt iv distributer, and older style crane cd box (has rev limiter but uses merc module for advance curve) and have switched to a v6-14 module. sweet spot looks to be about 30 degrees total advance.

your point on designing the engine for blower use from the beginning is well taken, but I figured that the current build was way pushing it in this boat anyhow... I fooled myself into thinking that I would just run it the way it was and be happy with it... like that's ever happened with any of my toys before...
 
Your boat sounds good and running great. you have to be happy with it. Everybody wants to go faster. The accomplishment of something you did that works well is rewarding.
Not to mention the adrenaline rush.
We can change the thread to big block small block power. I like them both always have always will.



MKHammer
 
mkhammer said:
Your boat sounds good and running great. you have to be happy with it. Everybody wants to go faster. The accomplishment of something you did that works well is rewarding.
Not to mention the adrenaline rush.
We can change the thread to big block small block power. I like them both always have always will.



MKHammer
Click to expand...

anything that makes noise and runs fast - bikes, boats, cars, etc... is a blast, and worth a big grin. Setting them up yourself and having it work (once in a while) is even better.

The prices you gave above and on your web site are very competitive. Your insight / experience in this thread as well as many others i've read are appreciated.

I'll definately keep it in mind the next time I go to order a list of parts, etc...

On a full new build for any of my toys, I would probably have Joey build the bottom end and he would get the parts for it. I have the luxury of living in an area with a long history of performance boat manufacture, etc... and there is no shortage of truly talented people around when you need work done. I want a boat that's a good bit bigger and a lot faster, but this little one has been great to experiment with and get some seat and wrench time on - before diving into something that I can't financially afford to screw up. have a great one!
 
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