I purchased a really beautiful 3.71 blower with Cragar drive and 3 belt pulleys. The very nice and honest HAMB seller told me that this blower would be best suited for a 283 engine. I have a 327 that i am planning to use in a 32 sedan. Would the 3.71 be enough for a 327? Or would it be better with a tri power set up? Trans wil be an auto....so wife can drive too... Thank you for the help
i have a 471 on a 327 (331) that still works well I think at 1 to 1 or slightly overdriven it should still make 5-7 psi which would be good .
You could always use a smaller diameter pulley for the blower to get more boost... Don't know if it will help or not....
Spinning it faster moves more air, creates more boost but, heats up the intake air and that robs power. The law of diminishing returns plays out here. There are some reference charts that size superchargers using cubic inches and rpms. Sounds like a cool vintage piece, post up some pics
Ok changed some plans. Removed the 283 that was on my 39 and that was needing rebuild, and plan to use with the blower on my 32 sedan. What is a good performance recipe for this little engine? Don't want an exotic or expensive to build engine, just some basic suggestions on getting the 3,71 and the 283 mix together. The car will be a 32 sedan with 350 trans. and rear will be a 8 inches with 3.00 gears. Want a good car for my wife....I called the family rod to get some approval from her... Thank you for the suggestions
Oh my god how about I trade you a 331 Hemi with a 6x2 Edelbrock EC6 intake for that setup!!! That's such a rad combo!!!!! I think that a 3-71 or 4-71 would be rated better for a 265 but I am sure you'll get some great number out of. PM Tudor here on the hamb and see what insight he has on the subject. He's a wealth of knowledge on blown sbc's and had a 6-71 on a 283 not too long ago. My advice might be that you would probably want a manual trans behind that if not for the performance then just to have the most fun out of it. Keep us posted!
I like the neat V belt drive, looks a bit more interesting than the usual toothed belt. Where did the pulleys come from? Are they custom made? I see Speedway do a triple V belt pulley in aluminum, not sure if that would be one way to go to coax the 6/71 to work on my 350. I'm after a bit of fun and looks, not 500 horses.
The smaller blower will not make much boost, but for looks it is excellent with the belt drive. As to how to build the 283, since you won't have much boost, it does not need crazy changes. Stock good condition bottom end, forged pistons about 8 to 1 compression. Run a fairly mild cam that has sufficient lobe separation like 114+ to help keep overlap down (you want to have the smaller boost stay in the combustion chamber). Overdriving the blower does reach a point of diminishing returns, and you are already on the past optimum point. Use the blower for looks more than performance and you will still have a nice driver.
Look at industrial applications, there are thousands of sheave's in any combination and size you can think of.
a 4-71 on a 289ci engine will make 5#'s boost @ 10% underdriven. so I'd imagine a 3-71 on a 289 would make 5#'s at 1:1 or even 10% overdrive, I'd call the guys at www.blowerdriveservice.com
Went to Bobby Walden shop today, and purchased the idler ***y and the top pulley. This stuff in new, and absolutely wonderful. QUality is excellent, and price adequate...not cheap for sure, but realistic and well proportioned to the quality of the product. Any idea about cam and compression I should use? Ok for a large lobe separation, like 114, but what about duration and lift? Trans will be a 4 speed and rear axle around 3.20 or similar. Compression? WIll be driven 1:1, so guess 8:1 with good forged pistons should be enough. ANy suggestions? Thank you
Think about this for a minute , all 71 series blowers were built for a 2 stroke diesel . I would think a 3-71 would work just fine on a 4 stroke engine even at 1:1.
The cam for a blower motor (or any motor) should match the intended rpm range of the engine, which depends on gearing, my guess is around 220 duration at .050" lift would put you pretty close. I don't know what pistons to run...kind of depends on the heads, but if you're running Power Pack or the pictured Camel Hump heads then flat tops will have too much compression. Might try flat tops with the old 2bbl 283 heads, as you probably don't want to ruin such a nice looking combo by putting some later model heads on it. Although you're not gonna be making much boost...so maybe you can get away with more compression.
The Jalopy Journal
