So I decided to go wandering around at the scrapyard a few days ago, and ended up finding two cranes with 4-71's. One is already ripped apart and hot tanked, so I need to figure out what to do with it. The first request, is for a blower rebuild- what needs replacing, tolerances, etc... are there any good books or websites out there that I need to look at? Also, I remember there was a thread on fabricating an intake, with a nice article on a hemi, but I can't figure out how to manipulate the search engine to spit out what I need. What would be needed to build an intake for a blower? All hemi setups I have seen come with either a 6-71 or an 8-71, however these have mostly been 392's. I have a lowly 331, will a 4-71 suffice, or will I need to step it up a notch to a 6-71? School me please, as blowers seem to be a very taboo subject among most racers and companies, while I would just like to build a reliable, streetable, 5psi motor. Thanks.
Sounds to me like you've got a good plan...here's one kind of recent thread on the subject. http://www.jalopyjournal.com/forum/showthread.php?t=51075 also here's some info from a 1961 cragar catalog, might show you what you're looking for, and how expensive it is....in those good old 1961 dollars. http://www.selectric.org/cragar/catalog08.jpg
pick up a copy of A Do-I-Yourself Guide to Street Supercharging, by Pat Ganahl he has assembled a very easy to read and informative pile of information there is even a section on rebuilding the 4-71
Cool, got that book on order. I've heard lots of good things about Corky Bell's turbo book, is the supercharging one an good? C'mon guys, I know more of you have faced the GMC blower dilemma- speak up.
If your after the real deal race look bead blast it, just knock the parting lines off of it and off the the blaster. If you're building it for a streeter you should think about adding a pop-off valve. It will allow you to bleed the pressuer off and make starting a little easier. Something else you might consider is o-ringing the block, or heads. I prefer to o-ring the block but if you aren't tearing you engine down the heads is a better bet. I'm sure that all of that is covered in ganahl's book. I'd gladly do a tech on a blower rebuild but I would need to use someone elses blower and dime. I just don't have the funds to do a huffed mill at this stage of the game.
Guess I missed the 5 psi. Huffing is like nitros, its an addiction, anything less than your first pop won't get you off. I always build with the intention of bigger n better. Guess that's backwards thinkin'.
I guess that depends on who it is, I've been running the same boring 7 psi on my blower motor since 1990.
I am setting up my first blower right now too. First of all - fucking Snatch is my favortie movie. I'm a fan of Bullet tooth tony myself. 5 psi should be no problem. I called BDS and had them send me their catalog. It is full of tables and set up techniques. Read that and then come with the questions. Also do a search on here - REJ and some others have discussed this at length. Good Luck
Borris, I haven't started yet, but here is what I think - take a blower top gasket, lay out the top holes and bolt holes. Drill and cut out with a jig saw. I would think 1/16" plate would be plenty sturdy. Then weld up the 4 sides. Use 2" carb spacers to lay out your carb postions, mount holes, etc. Use another 1/16" plate to make the top. Maybe go 1/32" on the sides. When you weld it it will be strong enough. Make the box 1" tall. Weld her up and bolt it on. I suppose you coud use a 3/8" thick plate, cut the holes for the carbs and tap the plate for the mount holes, then bolt that plate diretly to the top of the blower. The center bar in the blower opening is not flush with the top so oyu could still center that carb. Plenum Box or simle plate? What do you think???
I was just searching the H.A.M.B for a tech post about making your blower intake. But I want to see how it's done for a flathead. I have scored a S.C.o.T blower it's not the regular blower used on flatheads but a smaller one. Anyway it looks cool and now I need to make a intake for it so I can actually use it. There is the thread Kevin Lee started http://www.jalopyjournal.com/forum/showthread.php?t=92154&page=2&highlight=blower but did you finish it? Would be gret to see. I have been thinking about using a manifold for a 4 port carb and cut the top down and weld a mounting plate on it. This way I can keep the runners, since even a blown engine works better in the midrange with longer runners. Someone was asking about Corky Bells books. I have both the turbo and the supercharger books. The are pretty much the same book. I think they are a great source of information for both the beginner and the more experianced reader. //Magnus
Here's a couple of pics of the little sucker... errhh... Blower Pretty small but I think it looks cool.
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