old blowers and intakes

[olkyhippy]

back when drag racers started running old style hemis i think they used detroit desel blowers like the 6 cylinder blowers and the v8 318 8v71 blowers my question is whate kind of intakes they used and are any of these still around. there are still lots of the semi 8v71 blower trucks sittin in the junk yards . these blowers are dirt cheap if we just had a way to bolt them on.

[DblAdigger]

Well, it's not really a bolt on deal. Blower manifolds (new) are available from a few sources, Hot Heads, Weiand, PAW ). Then there is the blower. If you acquire a used, stock, GMC 6-71...it must be converted and overhauled. The case must have the "hook" milled off the base, rotors inspected and reversed, bearing plates replaced with stronger ones or, at least machined for reinforcing steel rings, drain holes plugged....the list goes on...AND, that's IF the case AND rotors are in good shape. Then it must be setup by someone who knows what they are doing, like how to shim the gears to "time" the rotors. The easiest way is to buy a kit, complete, from one of the above vendors.

[olkyhippy]

yea i realize you can buy a kit from vendors but i wounder whate the old racers used for intakes to bolt the old truck 8v71 blowers?

[DblAdigger]

I listed 3 sources above. The manifolds I ran were CRAGAR, unfortunately...they quit making manifolds years ago, just wheels now. Good luck finding one today. There were others. M/T (Mickey Thompson) was one. Most anything you find used will be a piece of junk requiring massive repairs ( welding, re threading, and re machining. Unless you're up for that...and the expense...new is probably cheaper. Good luck.

[olkyhippy]

thanx for your replys . i bet in the early days some body welded one up before the aftermarkets

[mart]

".....but i wounder whate the old
racers used for intakes to bolt the
old truck 8v71 blowers?"

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"What did the old racers use for intakes for the 8v71 blowers"?? The simple answer is 'nothing', because the "old racers" *didn't* use 8V71 blowers. The so-called "8-71" blowers (*note*-no "V" in the designation) you see on race cars nowadays are actually aftermarket 'stretched-case' replicas of the 6-71. Back in the day, GMC (later, Detroit Diesel) made inline 2, 3, 4 and 6 cylinder "71" series diesels and 'Vee-type' 6, 8, 12 and 16 cylinder "V71" series diesels. The blower cases that racers modified to use as superchargers always came off of the *inline* 3, 4, and 6-71 engines because the inline engine blower cases had a mounting flange on the base that could be bolted in a conventional manner to a manifold. The "V71" blowers don't use bolts or even have a mounting flange on the base. Instead, in the original 2-stroke diesel application, the case is wedged between the cylinders inside the 'vee' and held in place with studs and clamps that attach to the blower via ears cast into the sides of the case. With no conventional mounting flange on the base, there's no easy way of bolting a 'V-series' case to a normal manifold. Not to say that it absolutely can't be done, because 'Blower Drive Service' - to name one company at least - has come up with a unique manifold and a special mounting set-up that allows modified GMC/Detroit Diesel 'V-series' cases to be used nowadays. But 'back in the day'm when racers were still using OEM 'GMC/DD' blower cases, they all came off of the inline engines. Since then, racers have just about all switched to aftermarket cases and the aftermarket has responded with even larger sized, 8, 10, 12 and even 14 series blowers - (some sizes which GMC/DD never made even - and none ever, in inline form by the way), based on stretching the basic inline 6-71-style case design to accept longer rotors.

mart
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