blower trouble

I have a tired 6-71 blower on my 396 BBC. it looks very old and
used on sit on top a also tired dual quad induction system. the blower and dual quad came with the engine when i bought it.
should i just get a new 6-71 and dual quad induction, fix the old
one(if possible) or switch to a different blower and induction
system? what kind of blower and induction system do you guys
recommend?( if it helps, my engine has an 11:5:1 compression
it has 4 bolt main bearing caps.)

thanx in advance,
Quarter mile killer.


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You can have your blower rebuilt at any number of re-builders and you will need to drop the compression ,less you want to run alcohol.

the previous use to drag race the engine alot in his camaro. it
2,000 miles and has been rebuilt once. thank you for your info,
Roy.

Quarter mile killer.

with that compression ratio and a blower you would detonate you engine running any thing anything other that HIGH octane racing fuel. I'd lower your compression ratio before I even looked at doing anything with the blower.

howziit guy!

1)install 8:1 forged pistons;
2)send blower to any of the large, reputable supercharger companies for total rebuild;
3)decide on mild/moderate/bracket-race buildup;
4) " " " " /cast iron/aluminum heads;
5) " " " " cam;
6) " " undersize/overdrive blower operation, select pulleys;
7) " " rebuilding existing carbs, or calculate cfm needed, have blower company modify yer old/new carbs;
8)modify small-headed distributor for blower ignition curve;
9)upgrade to 2"-2 1/8" headers;
10)remove and discard mechanical fan;
11)upgrade radiator to accomodate extra heat;
12)install adequate electric fan(s) and shroud;

and don't forget to convert to short water pump.

First, is this just a race motor, or do you drive it on the street?

The others are right about the compression being too high, but only if you are trying to have this thing running on pump gas. If you're just racing this thing, then keep the pistons you have, get an injection set up and run alcohol. And with the tired blower, do like everyone else said, get it rebuilt. It's far more cheaper than getting a new one, and you could even get it polished to make it look like new on the outside.

the 396 i have is just the engine itself. it was an all out weekend
warrior that was not driven on the streets.

What do you know about the bottom end? You already stated that they are 11.5 comp pistons, but what about the rods and crank? Also, what kind of carbs are on top of it right now?

Is it possible to run 11.5:1 with a blower and not pop the lot?

Yeah, but with alchohol or good race gas...

Hang on, this engine was a weekend warrior,used to drag race a lot, has 2000 miles on it and only rebuilt once,hmmmm

I suggest before you put any more $ in it you send it to blower drive service (BDS).
They helped me out with a rebuild/parts upgrade for a old weiand 6-71 Im running on my track car.