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.)
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.
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. :sweat:
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.
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?
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.
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