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-   -   are these the right heads? (https://www.racingjunk.com/forums/showthread.php?t=17746)

hotrodharley 07-05-2007 07:53 AM

are these the right heads?
 
hi....i'm building a 540bbc with 11-1 comp/736 lift 114ccl/big bore 6/71 alky blower/enderle bird catcher hat/1;80 power glide trans[trans brake]/
i have a set of brodix 2-plus heads BUT i've had a few guys say heads to small..now what i need to know is should i sell and buy different heads?[what heads should i buy}have the heads i already have flowed for my engine combo.i'm on tight budget but want to do right also..by the way what would cost be to have heads flowed if this is way to go?never had a set flowed so don't any ideal cost on this type work.
thanks for any coments on this

edvancedengines 07-05-2007 12:26 PM

Harley you have a blower. Up the boost if it is not strong enough with what you have.

One of the fastest Outlaw 10.5W Cars in this country is using out of the box Brodix BB2X heads and tons of boost on it. Jimmy Blackman is his name.

What the deal is when you are blown is that better flowing and bigger heads to make the same power will not require as much boost to overcome port restrictions.

If I had those heads and it is what I could afford, I would put them on the sucker and expect it to fly once it got lined out.

I know this is different than you have been told and probably will be told but fact is fact. Jimmy Blackmon's car has Box Stock BB2X heads on it and he runs very strong. Of course the rest of his combination is a working combination planned and designed to work with those heads.

I have seen guys get rid of the older heads they had and were running a lot of boost with, go buy a trick set of heads and with no other changes bolt them on and run the same speeds as before but now it is showing much less boost with the newer heads.

I hope you are running Alcohol in that thing with that compression. If you remember I advised you appx 2 years ago on an MSN Web Site to blow it and use alcohol.; :) :)

Is this going in that awsum Camaro?

Ed

mcracecars 07-05-2007 01:31 PM

A 6-71 on a 540 is kind of small, need to spin the blower faster to get the boost you want...
I would suggest keep the heads and invest in a larger blower, a 10-71 or 12-71. or even a 14-71. THere is not a big price difference once you get over 8-71. Going to an 8-71 would not justify the cost.
There are always good used blowers out there, or something rebuildable at a decent cost...
I see you are on a budget, the suggestions are only if you have or want to spend the money. You can still use the 6, and change it later. Blowers are easier to change than heads.....

edvancedengines 07-05-2007 02:01 PM

I do agree with Ed,
You can overdrive the heck outa the 6/71 but it will heat and beat up the air a lot. It will work though.

The bigger blowers will need to spin less rpm so the air will be cleaner and cooler.

FRom what little I have learned about the High Helix Blowers is that the boost is instant and hard hitting. Maybe not what you would want.

I think they also make an interccoler style of blower intake manifold that would cool the mixture down. With alcohol that will be cooler too.

Don't forget to put a cranksaft girdle on the front to support the front of the crankshaft. That is very important.

Ed

zipper06 07-07-2007 11:09 PM

I agree with both ED's, you need more blower, you can then spin it slower and put twice the boost into the engine with less heat, and always run a crank support out front.
I personally run a 1471 on a s/blk overkill i know but i can put 30lbs of boost into the engine and not even spin it 1 to 1.

just my .02

Zip.

hotrodharley 07-08-2007 06:48 PM

THANKS EVERYONE SO FARE FOR YOUR HELP..YES I'M GOING ALKY INJECTED;;SO WHAT I'M GETTING HERE IS HEADS IS FINE BUT NEED BIGGER BLOWER THEN..I WAS TOLD THE BIG BORE 6-71 WAS SAME AS A 8-71..HAVE YOU-ALL HEARD THIS?


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