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Old 12-17-2017, 04:00 PM   #1
TJM & Co.
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250/six. Want good heads with lump work done

Rebuilding a 1975 -1 barrel Chevy 6 that had the integral head and intake.
Block has been hot dipped and magnafluxed. Good to go. We're going 0.030" to start off right.
Going with a 4 barrel throttle body injection. A "research" project for an automotive class.
Is there an a good aftermarket head with better porting than the OEM?
ie, no need to to do the lump addition??
Thanks.
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Old 12-17-2017, 07:28 PM   #2
GMDad
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Re: 250/six. Want good heads with lump work done

Contact Mike Kirby at Sissel Performance
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Old 12-18-2017, 08:05 AM   #3
D13
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Re: 250/six. Want good heads with lump work done

Do you have Leo's book? Did you join Inliners International?
There are no low-buck aftermarket heads currently available. There have been 'teasers' about a new head and / or re-release of one of the 12 port heads for a few years but I have not heard that this is reality yet.
Kirby / Sissel is considered the premier shop for head work for the factory heads.
12bolttom, Tom Lowe, also performs this type of work.
Lumps are available on ebay if you want to install them inhouse. Tlowe out some vids on youtube showing the procedure.
There is also a shop (kendra?) selling lump ported heads on evilflay but I do not know of the quality of their work.

Given the EFI I'm assuming this is to be a perfomance motor. I'm assuming Offy or Clifford intake, or even the PES version which takes a different lump package than a conventional intake (moves the floor of the runners and head higher).
Curious question - did you look at the CFM required to feed a 258? Most of the 4bbl EFI's are way overkill for this small a motor.

Enjoy the six, they are a bit pricey but lots of fun.
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Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping
Plus a mess o' tractors
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Old 12-18-2017, 11:59 AM   #4
Dead Parrot
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Re: 250/six. Want good heads with lump work done

What are the goals and limits for this class 'research' project?
Any budget limits?
Emission requirements?
Trying to show you don't have to have a large motor to make decent power?
HS kids or Vo-Tech for adults?
What are the plans for the rest of the drive train?
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Old 12-19-2017, 10:58 AM   #5
andyh1956
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Re: 250/six. Want good heads with lump work done

When I was in high school the dirt trackers were running a head on the 292s that was two SBC heads w/ a cyl sawed off each end & welded back together. Bolts right on the six block.
Made a "CrossFlow" head.
Looks like folks still doing it. Hope your school has "Deep Pockets"!
https://www.google.com/search?q=2+sb...=1513695763157

Last edited by andyh1956; 12-19-2017 at 11:05 AM.
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Old 02-01-2018, 12:33 AM   #6
TJM & Co.
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Re: 250/six. Want good heads with lump work done

Thanks for all the feedback, I'm new to this forum. I had found many of the resources listed. Leo's book seems to be the bible on the Chevy six, great info.
We will do a lump port kit and do the machining ourselves.
New cam, lifters, springs, with a bit more lift, Offy intake & 4 barrel EFI is a bit of "overkill" but we can tap into the signals and record data. A pressure transducer spark plug will record cyl. with respect to crank position so we can make p-v plots and see the effects of changing timing and load.
Just a good hands on project off the well beaten SBC trail.
I'll post as we go.
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Old 02-01-2018, 07:31 AM   #7
D13
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Re: 250/six. Want good heads with lump work done

Looking forward to it! Also on Inliners there is a person who fuel injected a Pontiac OHC six. Interesting reading.
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1982 250/TH350 beater in progress
Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping
Plus a mess o' tractors
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