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GM six "lump port"

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CoupeBoy
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GM six "lump port"

Post #1 by CoupeBoy » Mon Feb 10, 2003 11:20 pm

A couple weeks ago (month I guess) I bought a book
Chevrolet Inline Six-Cylinder Power Manual
by Leo Santucci
ISBN 1-931128-15-4
Its by California Bill's Automotive Handbooks.

It covers buildup and modification of the sixes quite well including some of the mods that every 6cyl owner should make. One of the mods that I was/am unfamiliar with is called the "lump port" where apparently you take the head into a machine shop and have them remove the divider inbetween the intake ports on the head. Then there is a little "lump" that goes in on the bottom of the newly opened port to better direct the intake flow. I am wondering if any of you have tried this or know anybody who has. It is supposed to really increase flow and efficiency (even more then the f*rd 240/300 separate intake runners) by acting like a large tunnel port.

any thoughts? ideas? real world testing?

I've got a '66 Malibu 4dr back home with a good running 230/PG now, however I also have a 250 and possibly a 292 to play with and I figure I might as well toy with high performance ideas while im at it.

ron

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Post #2 by Guest » Tue Feb 11, 2003 12:13 pm

Sup hometown.

I just picked up the book also. Pretty kewl deal.

Some of the fellas at Inliners.org are running them.

I'm gonna go back and read again, but I could have sworn the book mentions to only do so if you're going to have a HIGHLY modifiled L6. Otherwise, for the streets, just work and massage the "boss" some. That's what I did.

However, would like to know if there is anyone out there who has a lump-port head on a daily driver...

Ctown :checks:

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lump port

Post #3 by CoupeBoy » Tue Feb 11, 2003 12:31 pm

Nah, I was looking through the book as I was writing the post and its says that you *should* do the "lump" unless your an old blue-hair and don't care about performance.

The little 230 that powers my '66 malibu does a real good job at it, I think with some minor mods (ignition/carb/exhaust) it could be a real move/shaker.

I read that whole book on my round trip out to Portland a couple weeks ago, then had a couple evenings to chat with my grandpa who used to run the old 215/235/265's back in the day. Its a good read I would recommend it to anybody who has a GM 6.

ron

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Post #4 by Guest » Wed Feb 12, 2003 1:41 pm

READ pages 90-91...

and this time don't type while yer reading... 8)

CHEVYTOWN :checks:

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lumpy port

Post #5 by CoupeBoy » Wed Feb 12, 2003 1:53 pm

I'll have to do that when I get home, I attempted to use memory to type the part yesterday but apparently I need to re-read..

Why isnt there any information on the internet about Sissell or the lump port, I could read so much more when on the man's dime then I would ever have time for at home...

ron

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FYI:Aussie 12-port conversions

Post #6 by xctasy » Wed Feb 19, 2003 5:22 am

The GM Holden sixes from 1963 to 1981 ran Chevy 194/232/250-style heads and blocks in a scaled down format. They were raced in sedan class "tin-top" events, and had a huge amount of development. They had 3 intake ports which were served two intak e valves, but the exhast was a full six porter. The heads were called 9 ports until Holden saw the light in 1982-1985 and had 12-port heads from the factory. Port EFI was used form 1984 until the belated unleaded fuel area of 1986...11 years behind the US!

In Aussie, the GM Holden boys with there 130/138/149/173/179/186/202 9 port sixes ran an intake port divider. It consisted of grinding out the centre simease section of the intake ports wher the cylinder head bolts/studs go through, and replacing it with a thick wall 9/16" stainless pipe push fitted into the head with a sealer compound. Befroe the tube got pushed in, often an alloy wing was placed in to form a full 6 port intake where there used to be three. The Yella Terra company used to CNC machine the stock Red"Motor" casting, and sold it as part number BAT1200, (for Bathurst, the famous racing track Holdens have dominated for the past 35 years).

Just fitting the tube is a huge boost to air flow and power. The alloy divider, if done right, makes the head flow like a greasy rat down a drain pipe!

Most Aussie Holden guys will tell you that these 12-port heads are screamers...there right!
Image
XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

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Re: FYI:Aussie 12-port conversions

Post #7 by addo » Wed Feb 19, 2003 6:44 am

XECUTE wrote:Most Aussie Holden guys will tell you that these 12-port heads are screamers...

And every second one will remind them that the 9-port heads can have wilder porting than a 12. :P

PLUS: The integrated port dividers were outlawed in certain classes of competition, leading to the sneaky solution of welding the divider to the extractors, where it was then a legitimate exhaust accessory. :roll:

Adam.

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Post #8 by xctasy » Thu Feb 20, 2003 6:24 am

Excellent. I didn't know that! I guess shape is more important than size...um..when your talking about inlet ports, that is :oops:
Image
XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

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