I've got a question for you blower guys. I've got a *****in injected sbc with very good parts, crank, rods heads top of the line stuff. If I wanted to put a blower on it what changes would I need to make. I know I would need to change the pistons to a lower compression ratio but is there anything else I would need.
Required parts have a lot to do with what you plan to do with it once it's together. A blower *can* be put on a stock cast piston mill providing it isn't running much boost. What are your plans for it? And just some general stuff... Steel crank a plus, double key the snout for the lower hub. Good pistons as you mentioned. And cam with the right duration will help in cyl pressure. Quality head gaskets also a good idea. If you're going to run serious boost. Head studs.. Again, a lot of it will depend on what it will be used for. I ran a 6-71 on a mild 283 for years with NO issues at all, and it was not truly set up to run a blower. Tony
How much air do you intend to force into the combustion chambers? The major changes depend on how much boost you plan on throwing at it. Above 10 PSI your fuel demands go up exponentially, you should also plan on O-Ringing the block. Heavier valve springs on the intake so that the boost doesn't over ride them is also a good idea. A vacuum pump for the lower end is a pretty good idea, you can make one on the cheap from a Ford emissions pump. Even if I wasn't going to boost it to the max there are things that a blower motor likes: blower grind cam shaft is a must. A new valve grind, blower motors like broad flat faces on the valves. Or you can blow all that off and build it for looks. Tony you type too fast.
I run mine with a CR of 8.5:1 not to lazy with no boost and under WO throttle it is at 9psi on 91 octane gas 671 roots blower no detonation problems you would probably want to change out the cam for a blower grind wider lobe seperation and longer exhaust duration with the matching springs for the heads your timing will need to be changed all in by 2500 or so and 30 degrees total. You will produce more heat so a adequate cooling system will be required and your crank damper should be upgraded the stock ones tend to disinigrate over time with the added stress is running the blower and it is always costly when that happens. It is not as simple as bolting on a supercharger but it is not that difficult with a little bit of homework and patience. I am ***uming you will go with a carb and not the fuel injection if you are not you are out of my league. In the end it is worth it I drive mine all summer long and get 16mpg if I stay out of the throttle and have gobs of torque on command.
Lower compression, double key the crank, less gear in the rearend. The cam may or may not need to be changed, but we have no idea what's in it now so it's hard to say.
Thanks guys. It's for an altered, so no street use. My gut tells me to build a new engine with blower specific parts and leave this one alone.
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