AFBCamaro

Hey guys i just got my hands on a used(in good condition) 6-71 roots blower. It is a GMC diesel.

Before anyone says anything. I am building a 385(not finished) in the garage and was bored so now i feel like putting a blower on the 305 until it goes.

My 305 Camaro Currently does mid to low 14s in the quarter mile.

My question is does anyone know what you have to do to convert a GMC diesel blower to work on a Street engine?

I imagine that you must surface the bottom of blower flat to allow for fitment to the intake but asside from that can i just buy a drive, cover plates and stick it on like that???

I have found no information on this thing at all.

Thanks for your time!

Aron213

there are two types of DDC 6-71 blowers. Sounds like you have a V series which is not the one you would want.The other one is already flat on the bottom. It would cost quite a bit to get this project up and going, plus the fact that since DDC hasnt made new 2 stroke motors for awhile, most of these blowers are in need of rebuild, unless its a rebuilt unit already.

Im not going to touch the fact that your trying to do this to a pretty much stock motor 305.

Jim85IROC

iTrader: (2)

ka......

Jim85IROC

iTrader: (2)

....Boom.

AFBCamaro

The blower I have now is not the V unit it is a real 6-71 and its already flat on the bottom.

I only have the blower itself. Im fabricating a single carburator plate out of aluminum. It will be feed by a 930cfm variable venturi predator carb. Maintains the fuel at a constant 12.5 mixture throughout the range.

I will put 76cc heads ported by me. So compression will be at 7.6s. Then I am shooting for around 8psi with water injection to ward off detonation. Should be pretty safe.

I need the end covers and the drive mechanisim which i heard is patetically expensive. But you cant beat that 3 inch thick belt sicking out of your hood. :-)

What I need to know is the general things needed to convert. I just heard that all you need to do is put on new bearings(if needed) check play add teflon strips and put in drive mechanism. Im I correct or do i need to do anything else!

Thanks for your time guys.

Jim85IROC

iTrader: (2)

with that ultra low compression and water injection, I would think you could do a ton more than 8 psi.

f-crazy

iTrader: (-1)

i agree, if your putting it on to blow it up then make it good lol...dont spin a bearing like i did, throw some rods on the road lol

how would u get like 30 psi out of that blower?

dans82bird

you don't need that low of compression... 8 to 1 or 8.5 to 1 would be sufficient.. if not optimal. you might try posting this message on the power adder board for some more opinions though

Air_Adam

To get the most outta that blower, you should get a cam for your motor... there are special grinds out there specifically for blower use.

Jza

It's a little more in depth than just checking play. Adjusting end play and rotor clearances takes machining, which is a royal pain in the ***, therefore you'd want to get it right the first time. Which means measuring and measuring and measuring.

I'm willing to bet you can make one hell of a 305 with that blower on it though. If I had it all to do over again, a blower would have been the first mod I made to the 305. A roots blower is great for street motors.

bigbze

A 6-71 converted to gas is not that hard contact dean blowers he has everything you need and pretty cheap to about $150 bearing seals triple pin kit etc. as far as a single car plate a 6-71 intake will work much better and there only $370 from summit.

OrangeBird

iTrader: (1)

if he hasn't figured it out in 11 or so years , He's not very likely to be still tryin

Thread date 2003

mlbinseattle

Oh well. It was his first post. He's new.

bigbze

Lol I didn't realize how old it was.

tunatrky

Still, maybe somebody else will see this and post pictures of their 305 with a diesel blower on it. I was reading this thread in suspense. OP needs to deliver!

bigbze

I actually just got home from picking up a 1979 Monza that I think came with a 305, not sure hanvt ran the numbers yet. But either way I'll be doing a build thread on the 6-71 setup

cuisinartvette

Wow one that never rusted to dust, def post up about it.
Thought those were cool cars or the mirage with the funky stripes.
Who didnt have a model of that one way back when

ddeennis

I did a budget 6-71 blower build, bought a used blower of ebay for 350 bucks, tore it down, got parts from deans blower service, did everything in my shop, no machine work, updated the bearings, set the timing with shims. did a pretty good post over on another board that like to talk about chevelles.

2 years later and my budget blower doing well on a 468 10.2 to 1 compression bbc.

Not as bad as everyone makes it out to be, do one for yourself and
then you know whats really involved, I think all the talk on the net scares
many away from doing more homebuilt blower builds.

the toughest thing for me was the timing of the rotors, I had to look at an old military mechanic book online on how to understand the checking points of the rotor clearence. everythng else was cake walk.

I bought some books on supercharging and bought deans dvd lots of good info on how to build your own blower. it just lack the timing points for clearence.

my blower is 12% underdriven and builds 5 psi of boost on my 468 with 325cc runner heads and two way too small 600 holley vacuum secondary's

t-top havoc

iTrader: (3)

Always the fan of In Your Face roots blowers, this caught my attention.
ddeennis, can you post or PM me the link for your rehab?
Thanks!