Technical GM 4-71 blower

I got a pair of 4-71 Detroit Diesel blowers. I’m considering keeping one and running it on the 383 in my’59 GMC and selling the other one. Is there still a market for these? Also, any tips or suggestions are most welcome. I’ve never had a blower motor, so I’m a rookie. With an extremely limited budget, I figured I would have to dig up the manifold, blower drive, etc. at swap meets.

 

Their are many threads about 4-71 & other GMC blower sizes , most are going to point you to search threads unless there's a pacific question that you have.

 

Sell'em both, buy a fresh 6-71...ready to go.
You'll be much happier, from beginning to the first trip down the street.

Mike

 

I would possibly be interested in one if you wanted to sell it. I have a 315 Hemi i want to put in my 41 Plymouth pickup.

 

like Mike VV said , even if you do most of work its adds up
Just average prices
$3000 -4,500
The most expense will be intake
A 4-71 $450-600
But you could use a 6-71 around same price with 1/4- 1/2 aluminum plate to adapt,
Or make a plate to bolt to a single four or dual four intake like before production intakes were made

 

4-71's are cool

 

That looks soooo dang cool!

 

Whoa! a 4-71 on a 4 barrel intake?!! I've got to see this setup.

 

I recall a recent post (may have been an old one bumped up?) of a member casting and machining 4-71 intakes. From Australia as I recall.

 

In mid 50s HRMagazine,
If you are new to Hot Rodding ,
What about direct drive the blower to front of crank , No chain or belt before belts , I think Moon was first company to do so ,
Lot of thing guys where doing , being creative,
About two months ago there was a thread started where someone found a article how to get over 400 some cubic inches out of a small block Chevy and I think it was before 1964

 

Back then most used Vbelt as power increased more V belts where add because of slippage, some used chain then 1/2 belts by Crager

 

Remember Flat Head Ford?

 

I thought he was making them for a SBC? Oh well, partial memory is still working

 

Get a 6-71 manifold, and make a pyramid adapter, to run BOTH 4-71s!

 

I like the way you think!

 

The adapter would be made from flat aluminum plate.

Three flats, and two triangles. Carb adapters would be similar.

If I had two, and a 383, I would already be welding.

 

Or............

 

Not Busting on the OP might be new to this Disease, now we will have to up load a pic, I think Gimpyhotrod is the
""Y"" manifold , 2 4-71 @ like a 45 degree angle??!!!

 

This is the stuff I like to see & share ,
Guys that thought outside a of the box & an imagination to go fast!!!

 

Wouldn't a 4-71 be to small for a 383?

 

Probably at its max ,6-8 pounds of boost on a 383 500-550hp under boost maybe 570ish just taking a guess without doing the math

 

Since they are not yet converted, I would keep the the lip on the edge, to help with mounting.

I am not sure what the angles would be.

Like this:

 

I'm putting a 471 on a flathead right now but 2?? I like 2 much more betterer haha. Thats rad. I wish I had never seen this and so does my wallet!

 

Holy sideways induction, Batman!

 

I would build the adapter so that the 4-71s are pushed forward so that the front surface of the cases are where a 6-71 would be, on that same manifold, so that all 6-71 drive equipment could be used.

Extra-long snouts are less common, and often cost more.

 

You’re pouring vodka on your cheerios again Douglas.

 

I honestly can't say what the biggest expenses , blowers cases with rotors or the extra parts needed to compleat,
$1,500-2k
Mix of new & used

 

Wouldn’t a 4-71 be perfect for a street driven SBC powered hot rod. To me 6-71’s look almost too big on a SBC unless you are a serious racer.

 

Onn a 283, maybe. A 4-71 would need to be overdriven by quite a bit to make decent boost on an 383.

 

I have a 3-71 which is one step smaller than the 4-71 u are tinkering with. I built my own manifold using a 2-2 flathead intake as a base. Looks good on paper, but not ever run or tested.