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Old 10-10-2007, 01:43 PM
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6-71 Detroit Diesel Blower Conversion

I am currently putting together a SBC 350 and have the option to pick uo a 6-71 detroit diesel blower REAL cheap. I was wondering if someone could explain the conversion process to me to flow it for gas? Is it even worth it?should I save my money and and buy a completed out of the box one?

The guy selling it says I can get a manifold for the block and a manifold for the carbs. Does anyone know where or what I should be looking for?



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Old 10-10-2007, 01:54 PM
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I do know that it is an expensive process to convert one over to gas. They basically are blueprinted. All clearances are tightened up, bearings are upgraded, end plates replaced and such. Then there is the polishing that could go along with it. You would probably come out cheaper by just using the one you can get as a core for a re-manufactured one that is all ready to go. I would call "The Blower Shop" and ask them.

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Old 10-10-2007, 02:11 PM
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Get this book. It explains how to set up a -71 blower from scratch.

As installed on Detroit Diesels, these blowers are just that... blowers. They don't make any boost on the diesels, they just blow fresh air into the cylinders to help scavenge them. The in-line Detroit Diesels are two-stroke, as you may know.

To adapt them for hot rod motors to make boost, you'll need to change out the bearings, tighten clearances, add a belt drive, and get a manifold and a carb adapter plate. i think there is some machining involved to the base of the case, also, but I'm not remembering for sure. I'll check my copy of the supercharger book I mentioned above tonight.

As Vince says, you may be better off sending the core to one of the blower shops in a trade for a complete kit.
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Old 10-11-2007, 07:21 AM
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Vince and Lee,

Sorry guys, but I'm going to have to disagree on this one. I've run an original GMC 6-71 for 8,000 miles with no problems. And it will pump up to 15 PSI at 5,000 on my little 4.6 liter. It's setup under driven, but it can be setup with what ever pulley sizes CaseyK1977 needs to get the boost he wants.

I started with an original case, rotors and gears. Yes, I did need a blower drive setup, aftermarket end plate, bearing kit and gaskets. Unless, your running high boost or using it in a drag racing application, I don't see the need for a lot of expensive machine work and teflon strips on a street car (I'm assuming thats what he is doing).

One side of the blower has "feet" where it hangs off the motor in the original installation. Yea, they can be machined off, or cut them off with a cut off wheel and dress with a belt sander. That works too.

There is a process to timing the rotors, but it's not rocket science either. Some feeler gauges and a little patience will do.


I'm assuming when you say good price, it under $100? That would be worth it because you can always sell it for more than that (you do need to check it for scoring and gouges first) Most of what you need can be found on Ebay, BDS or any of the blower suppliers. Check BDS website, they have charts to figure your boost vs rpm so you can pick out pulleys.

You are probably looking at over $1,000-$1,500 by the time your done (not including carbs) where as your looking close to $3,500 for new.

This site also has some good tips on building a blower

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Old 10-11-2007, 08:30 AM
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here is a list of places I have saved to help with a blower build. They are not in any order. There is all the info you need on the net to build a blower for the street. It is a lot of work and if you have never done one you might be better off to buy a complete kit the first time around.




Also be aware that the blower set up takes a different cam than a naturally asperated motor.
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Old 10-16-2007, 09:34 PM
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stock blower

stock blowers straight off a deisel needs lots of work to make it streetable.

Last edited by 68NovaSS; 01-08-2013 at 01:16 AM. Reason: Ad offering services - see Board guidelines
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Old 01-07-2013, 10:13 PM
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WOW , I am speachless, where did you guys learn all about blowers?how -to CD ** Rebuild kit ** rear plate optional **, your time to do the work about 1 day if you dont F%#@ up , polishing $*** depending on show class you want. never tighten up clearances, loosen them, tighter will melt your rotors down , sure if you want max boost and can aford a new blower every season at the drags by all meens choke the clearances, a street blower is not a drag race blower, you can run forever at 7lbs boost, 15lbs boost on a 4.6 ? not for very long, it seems we allways brag about the engines we blow up and have fun doing it. sorry for stepping on any toes especially for my neighbor in union, wa, Rick lilliwaup wa

Last edited by 68NovaSS; 01-08-2013 at 01:15 AM. Reason: Offer for services, see board guidelines
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Old 01-08-2013, 07:06 AM
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I would hope in the 5+ years since the thread was current that he's figured it out.
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Old 01-08-2013, 08:57 AM
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5 yr old.....Burned again. Who dredged this one up??

There is pleny of more up to date blower stuff now.
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Old 01-08-2013, 09:00 AM
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i've ran old deisel blowers on my race car for over ten years . for what the average joe wants there plenty good . By the way good, CD dean very imformative! this stuff isn't rocket science
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