i have a 427 talldeck. bored .030. flat top pistons. 123cc truck heads. guessing its around 8-1 compression. what do you guys think? i was wondering how a blower or a turbo would do on this thing. and which one would you recommend. also wondering what cam would work. thanks.

When you say "blower" what kind of supercharger are you interested in (Centrifugal, Roots...). If it's a roots blower you are after, I would opt for the 8-71.

I would probably consider turbo charging though. Unlike a roots type blower it's possible for the turbos to spool up later in the RPM band which really helps with traction off the line. Unlike the Centrifugal and roots blowers a turbo isn't belt driven so it won't cost you the horsepower of a belt driven system. However fabrication to tie your turbos into your exhaust can be pretty expensive.

Are your pistons forged? If so great, if not I think you are playing with fire and will have to limit your boost (which totally negates the idea of a blower motor). If you don't plan on going too radical with your RPMs (past 6500RPMs), then a cast crank and factory rods with good rod bolts will do just fine. RPM kills parts faster than anything...not horsepower. However it's still nice to have a forged bottom end.

Your head choice is also going to be a limiting factor. I don't know what kind of work you have done to them or how well they flow, but a general rule of thumb with a roots blower is the bigger the head the better. Unlike with a naturally aspirated motor the port velocity of the heads is not a concern because the blower makes it's own port velocity. If you plan on running a pretty large amount of boost you should consider having your block o-ringed.

As for a cam. With a roots motor you want something with a LSA of 112-114...preferably 114. Forget 110 or 108...you'll just spit it all out the exhaust. You don't need to go too radical with the lift (that's not to say it won't put out more power with more lift if your heads can use it). The cam can be fairly mild because the blower will do most of the work.

If you plan on running more than 4 lbs boost, you probably need to have forged pistons, and very good rod bolts. Sorry I just noticed Stingray just listed that! graemlins/clonk.gif At any rate, your compression is just right. graemlins/thumbsup.gif

i have a 427 talldeck. bored .030. flat top pistons. 123cc truck heads. guessing its around 8-1 compression. what do you guys think? i was wondering how a blower or a turbo would do on this thing. and which one would you recommend. also wondering what cam would work. thanks.


Old post....

Are you running stock type tall deck pistons (4 ring lands)?

If so, I wouldn't recommend using those pistons on anything that will see above 4000 RPM. Those pistons are extremely heavy and will come apart if rev'd too much. Been there, done that.

A cheap way to get around buying custom 427 pistons is to run 0.400" longer rods (6.535") with a standard deck 427 pistons. This also works if you are using a 427 tall deck block for a 454/496 buildup with pistons intended for use with stock length 6.135" long rods.