Inline 6 upgrades and recomendations??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72freak · 04-11-2007, 03:35 PM

I brought home a 1967 Short, step, 2x4 last week and started to play with it. Once I cleaned it out, pressure washed it, aired the tires and got some gas running through it I realized I have a failry nice, fairly rust free, good running truck. I have never done much with the inlines so after reading a few links I figured I would ask what recomendations you inline guys have for it.

It obviuosly has been someones project/baby because it has had some things done to it. Header and HEI.

Also..I have seen a few tranny links but I will ask anyway........it has a three speed converted to the floor. What 4 or 5 speed can I hook to it EASILY?

shifty · 04-11-2007, 04:05 PM

HEI is the biggest, nicest upgrade IMHO.

You can swap out the intake for a dual-carb intake, or just buy a single 1bbl carb Offenhauser or Clifford intake. Headers are another upgrade, but tough to find ones that fit on a 250 without having to modify the shape of one or two tubes.

PanelDeland · 04-11-2007, 05:57 PM

If you want more info on the inline check out
www.inlinersinternational.com
Those guys invented inline performance.

jbon64 · 04-12-2007, 07:41 PM

Quote:

Originally Posted by PanelDeland

If you want more info on the inline check out
www.inlinersinternational.com
Those guys invented inline performance.

or check out www.inliners.org as well

Spanky_Pete · 04-11-2007, 06:14 PM

I'm running headers, HEI and a CliffordPerformance intake with a Holley 390CFM carb on mine. It's not quite dialed in yet, but made a huge difference. With the 3.73 gears it's almost impossible to get going in first without breaking the tires loose.

davidh · 04-11-2007, 06:21 PM

there's a 4speed they put in 250-6 trucks in the 80's. Its a 3speed with an overdrive. I'm thinking about it for mine. but the 3 on the tree is a neat conversation piece.

Americanrider · 04-12-2007, 12:22 AM

Saginaw 4 speeds are cheap and mostly durable, same size/bolt pattern as your 3 speed so there is no changes to the drive shaft. Plug & Play if you have a floor shifter.

mnunn454 · 04-12-2007, 06:19 PM

Supercharge it with a centrifugal charger of some type.

There's plenty of room under the hood.

The plumbing wouldn't look as bad as it does on top of a V8.

The bottom end's already strong enough to handle modest amount of boost (say 4 PSI give or take)

When you lift the hood at a cruise night this season, you'd very likely be the only "SuperC' 6" in the lot.

724x4a/cchevy · 04-12-2007, 06:39 PM

Quote:

Originally Posted by mnunn454

Supercharge it with a centrifugal charger of some type.

you'd have ALOT of room! That would look killer!!

PanelDeland · 04-12-2007, 09:14 PM

72 freak check out a "Georgia Strret Rod Association" meet.There is one in Feb and they go to a lot of other shows.One of their officers(sorry I don't remember the name) has a 47-54 Suburban with the 6 and SC.It is a neat package and runs strong enough to tow a trailer for the GSRA.

JAKES 68GMC · 04-12-2007, 09:30 PM

I'd love to have a short step 67-72 with a souped 292/ 3 or 4spd.

Soup the six up if the truck is going to be a cruiser. It will be different, cool, and definately have a cool sound to it.

ThatOneBlue67 · 04-12-2007, 09:54 PM

They have REALLY cool sounds. Long tube headers and TRUE dual pipes.

JAKES 68GMC · 04-12-2007, 09:59 PM

Don't forget the Smithy steelpacks. Those are MANDATORY on a inline 6cyl.

**special-K** · 04-13-2007, 06:26 AM

You can bolt up any of the car 4spds that came in Chevys.There are guys doing turbos on I-6s,lot`s of room.

ronh72c10 · 04-13-2007, 08:42 AM

Any performance heads available for the straight sixes? I saw a thread on the HAMB about 12 port heads and have read about "hybrid" heads made from two SBC heads and wondered what's available.

Ron

Blue71LWB · 04-13-2007, 03:44 PM

With mild upgrades , maybe dual carbs or 4bbl with intake , headers and a mild cam ,

What do you guys think would be an obtainable HP rating? or maybe more important --- torque rating ? with a 250

69_hafton · 04-13-2007, 08:48 PM

If it runs good, I'd just drive it. The upgrades would depend on what you want to do with it. For day to day driveability, the first upgrades I would do: power steering, HEI (already done on yours), NP A833 3 speed w/ overdrive or a t5 5 speed with overdrive. I believe any Saginaw or Muncie will bolt up. The high rear gearing in a six equipped truck make it a prime candidate for an overdrive in a truck being built for highway use, unless you want a tough 4 speed (a muncie for higher HP) and are willing to change out your rear gears also.

On the wish list: a bigger carb, dual cast iron exhaust manifolds with dual exhaust (unless high quality, headers are short lived), rework the head to flow better.

retodd7711 · 04-14-2007, 08:27 AM

aslong as we're on the subject anybody got pix of a modified 6 in a row?
I'd like to see the dual carb or a super charger

**passthebuck** · 04-14-2007, 12:00 PM

You can do a few upgrades to an L6 head. The normal polish/3 angle, etc. The big problem is the headbolt passage that runs right through the centre of the intake port. I've heard of guys machining it out, adding an access plug in the roof of the port & using a lowprofile allenhead bolt that sits on the bottom of the port. Since the head is comparitively long, they tend to almost always need to be machined flat too. 250's use 307 pistons so you can easily get performance pistons.

04-11-2007, 03:35 PM	#1
72freak Rottenwood Garage Member Join Date: May 2005 Location: Marietta, Georgia Posts: 4,321	Inline 6 upgrades and recomendations??? I brought home a 1967 Short, step, 2x4 last week and started to play with it. Once I cleaned it out, pressure washed it, aired the tires and got some gas running through it I realized I have a failry nice, fairly rust free, good running truck. I have never done much with the inlines so after reading a few links I figured I would ask what recomendations you inline guys have for it. It obviuosly has been someones project/baby because it has had some things done to it. Header and HEI. Also..I have seen a few tranny links but I will ask anyway........it has a three speed converted to the floor. What 4 or 5 speed can I hook to it EASILY?

04-11-2007, 04:05 PM	#2
shifty Questionable Join Date: Mar 2005 Location: Atlanta Posts: 13,376	Re: Inline 6 upgrades and recomendations??? HEI is the biggest, nicest upgrade IMHO. You can swap out the intake for a dual-carb intake, or just buy a single 1bbl carb Offenhauser or Clifford intake. Headers are another upgrade, but tough to find ones that fit on a 250 without having to modify the shape of one or two tubes. __________________ If I've got anything up for grabs, it'll be here: 7-hole gauge cluster for a 67-72 p/u FREE (link) I can't check the forum daily. If I don't reply to you within 24 hours, drop me a PM! I'm (hopefully) still alive and will reply faster to a PM.

04-11-2007, 05:57 PM	#3
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Inline 6 upgrades and recomendations??? If you want more info on the inline check out www.inlinersinternational.com Those guys invented inline performance. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

04-11-2007, 06:14 PM	#5
Spanky_Pete Too many trucks? Nah... Join Date: Mar 2002 Location: SW Washington State Posts: 154	Re: Inline 6 upgrades and recomendations??? I'm running headers, HEI and a CliffordPerformance intake with a Holley 390CFM carb on mine. It's not quite dialed in yet, but made a huge difference. With the 3.73 gears it's almost impossible to get going in first without breaking the tires loose.

04-11-2007, 06:21 PM	#6
davidh Senior Member Join Date: Feb 2004 Location: Ponca city now kingfisher Oklahoma Posts: 1,221	Re: Inline 6 upgrades and recomendations??? there's a 4speed they put in 250-6 trucks in the 80's. Its a 3speed with an overdrive. I'm thinking about it for mine. but the 3 on the tree is a neat conversation piece. __________________ Even the nicest dodge-chrysler is only 2years away from being parked outside of Section 8 housing.

04-12-2007, 12:22 AM	#7
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	Re: Inline 6 upgrades and recomendations??? Saginaw 4 speeds are cheap and mostly durable, same size/bolt pattern as your 3 speed so there is no changes to the drive shaft. Plug & Play if you have a floor shifter.

04-12-2007, 06:19 PM	#8
mnunn454 Registered User Join Date: Dec 2006 Location: Rhode Island Posts: 602	Re: Inline 6 upgrades and recomendations??? Supercharge it with a centrifugal charger of some type. There's plenty of room under the hood. The plumbing wouldn't look as bad as it does on top of a V8. The bottom end's already strong enough to handle modest amount of boost (say 4 PSI give or take) When you lift the hood at a cruise night this season, you'd very likely be the only "SuperC' 6" in the lot. __________________ 69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe

04-12-2007, 09:14 PM	#10
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Inline 6 upgrades and recomendations??? 72 freak check out a "Georgia Strret Rod Association" meet.There is one in Feb and they go to a lot of other shows.One of their officers(sorry I don't remember the name) has a 47-54 Suburban with the 6 and SC.It is a neat package and runs strong enough to tow a trailer for the GSRA. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

04-12-2007, 09:30 PM	#11
JAKES 68GMC Aluminum slot wheels rule... Join Date: Jan 2006 Location: Maine Posts: 6,212	Re: Inline 6 upgrades and recomendations??? I'd love to have a short step 67-72 with a souped 292/ 3 or 4spd. Soup the six up if the truck is going to be a cruiser. It will be different, cool, and definately have a cool sound to it.

04-12-2007, 09:54 PM	#12
ThatOneBlue67 I survived Dead Man's Curve. Join Date: Apr 2006 Location: The Nine-Five-687 Posts: 389	Re: Inline 6 upgrades and recomendations??? They have REALLY cool sounds. Long tube headers and TRUE dual pipes. __________________ "The people should not be afraid of their government. The government should be afraid of it's people." "The Hurricane" 1967 Chevrolet C10 350 Eight Cylinder, 700R4 BowtieOverdrive *Cherry Bomb...* Disturbing the Peace Since 1968.

04-12-2007, 09:59 PM	#13
JAKES 68GMC Aluminum slot wheels rule... Join Date: Jan 2006 Location: Maine Posts: 6,212	Re: Inline 6 upgrades and recomendations??? Don't forget the Smithy steelpacks. Those are MANDATORY on a inline 6cyl. Last edited by JAKES 68GMC; 04-12-2007 at 09:59 PM.

04-13-2007, 06:26 AM	#14
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,859	Re: Inline 6 upgrades and recomendations??? You can bolt up any of the car 4spds that came in Chevys.There are guys doing turbos on I-6s,lot`s of room. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

04-13-2007, 08:42 AM	#15
ronh72c10 Senior Member Join Date: Jul 2003 Location: Mount Forest, Ontario, Canada Posts: 978	Re: Inline 6 upgrades and recomendations??? Any performance heads available for the straight sixes? I saw a thread on the HAMB about 12 port heads and have read about "hybrid" heads made from two SBC heads and wondered what's available. Ron __________________ 72 Chevy C10 (rust repaired, starting body work) 72 GMC 3/4ton 4x4 72 Chevy C20 Suburban 38 Ford Tudor Humpback Sedan (from the darkside) 67 Pontiac Parisienne 55 Studebaker Commander 2dr Hardtop (Starliner) My Youtube channel with Video Updates!

04-13-2007, 03:44 PM	#16
Blue71LWB Registered User Join Date: Nov 2006 Location: Alabama Posts: 120	Re: Inline 6 upgrades and recomendations??? With mild upgrades , maybe dual carbs or 4bbl with intake , headers and a mild cam , What do you guys think would be an obtainable HP rating? or maybe more important --- torque rating ? with a 250 Last edited by Blue71LWB; 04-13-2007 at 03:45 PM.

04-13-2007, 08:48 PM	#17
69_hafton Sleep-Deprived Join Date: Sep 2002 Location: Tulsa, Oklahoma Posts: 445	Re: Inline 6 upgrades and recomendations??? If it runs good, I'd just drive it. The upgrades would depend on what you want to do with it. For day to day driveability, the first upgrades I would do: power steering, HEI (already done on yours), NP A833 3 speed w/ overdrive or a t5 5 speed with overdrive. I believe any Saginaw or Muncie will bolt up. The high rear gearing in a six equipped truck make it a prime candidate for an overdrive in a truck being built for highway use, unless you want a tough 4 speed (a muncie for higher HP) and are willing to change out your rear gears also. On the wish list: a bigger carb, dual cast iron exhaust manifolds with dual exhaust (unless high quality, headers are short lived), rework the head to flow better. __________________ 1971 K/10 Long Fleetside 350/350 - 6" Lift 1969 C/10 SWB 292 - Sold It



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04-14-2007, 08:27 AM	#18
retodd7711 chrome makes it go FASTER! Join Date: Feb 2007 Location: Cleveland Tennessee Posts: 2,884	Re: Inline 6 upgrades and recomendations??? aslong as we're on the subject anybody got pix of a modified 6 in a row? I'd like to see the dual carb or a super charger __________________ She can't cook and she won't clean. But she looks good in a skirt and she brings me beer. She can stay for now. EDIT:: But she left me anyway, So forget her. 1962 GMC Stepside V6 4 speed My rolling resto thread http://67-72chevytrucks.com/vboard/s...d.php?t=324226 My old farm truck http://67-72chevytrucks.com/vboard/s...=1#post3465005

04-14-2007, 12:00 PM	#19
passthebuck Sisyphus was my mentor! Join Date: Sep 2002 Location: Carleton Place, Ontario CANADA Posts: 984	Re: Inline 6 upgrades and recomendations??? You can do a few upgrades to an L6 head. The normal polish/3 angle, etc. The big problem is the headbolt passage that runs right through the centre of the intake port. I've heard of guys machining it out, adding an access plug in the roof of the port & using a lowprofile allenhead bolt that sits on the bottom of the port. Since the head is comparitively long, they tend to almost always need to be machined flat too. 250's use 307 pistons so you can easily get performance pistons. __________________ passthebuck #5642 -TWO 1967 GMC 910's. One with L6/3-on-the tree and the other with 355 w/435hp & a 700r4. -a 2013 Honda Civic as my "sensible" car

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