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Airwreckc
Eric Cumming
RTP, North Carolina
(247 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

LS manifold for Buick 300?
Posted by: Airwreckc
Date: January 26, 2024 11:46AM

Hi guys,

Has anyone looked into what it might take to modify one of the fabricated low profile LS manifolds to work with a Buick 300? I am looking into using one of the EFI (such as Sniper) and the idea of a low profile, high flow manifold is very appealing--and these manifolds are fairly inexpensive. I know the bore spacing is off, but I'm thinking that cutting and rewelding the runners might be possible and not too difficult. Thoughts?
5516.jpg


mgb260
Jim Nichols
Sequim,WA
(2462 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: LS manifold for Buick 300?
Posted by: mgb260
Date: January 26, 2024 02:59PM

It would have to be custom, as the port arrangement is different with both center ports side by side. A guy on V8Buick made one. I'll link it to here. [www.v8buick.com]

Pic of homemade tunnel ram
215 tunnel ram 8-21-03 004.jpg



Edited 1 time(s). Last edit at 01/26/2024 03:22PM by mgb260.


Airwreckc
Eric Cumming
RTP, North Carolina
(247 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: LS manifold for Buick 300?
Posted by: Airwreckc
Date: January 26, 2024 09:37PM

Thanks Jim. I guess this confirms that if you imagine it, someone has already done it. I'll check it out.


Airwreckc
Eric Cumming
RTP, North Carolina
(247 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: LS manifold for Buick 300?
Posted by: Airwreckc
Date: January 29, 2024 01:06PM

Hi Jim,

I'm not sure how I missed it before, but I see that lots of people have used the Rover EFI with the upper and lower plenums. Since I'm planning a Buick 300, are you aware of anyone that has made one of these physically fit the 300? I was thinking one for the 4.6 might be the closet from a displacement (assuming I used the 4.6's ECU) and block size perspective, but it's only a wild guess on my part. I have read Curtis' excellent writeup on the Rover EFI, especially about the need to modify the height of the plenum and intake horns, but he doesn't mention anything about the 300. These sure seem attractive from a price perspective: [www.ebay.com]

Thanks as always.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6469 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: LS manifold for Buick 300?
Posted by: BlownMGB-V8
Date: January 29, 2024 03:24PM

To fit the Rover intake you need a lifter valley cover and adapter side plates to close the gap. A better choice is probably to get in on the first order of the new 300 single plane with injector bungs coming from Australia. Do a search on the MGExperience forum.

Jim


Roverbeam
Chad McNeely
N.E. MO
(73 posts)

Registered:
06/09/2021 06:03PM

Main British Car:
Alpine S4 Rover 4.0

Re: LS manifold for Buick 300?
Posted by: Roverbeam
Date: January 29, 2024 04:29PM

Funny, since I (now) have a 300 in my shed again, without an intake, the other day I took a Rover intake and plopped it on to see how it would look. I've never liked that side-intake plenum, and I'm a better composites guy than an aluminum welder, so I'd be making something different for that - but the lower manifold could be made to work without too much trouble.

The spacers you would need correspond to the difference in deck heights - Buick 300 @ 9.543 deck height, versus Rover's 8.960, so .583" of spacer. I'd buy some 1/2" G10 and trace the intake gasket pattern on it and go to town jig-sawing and filing it to suit. Adding a 2nd gasket would come "close enough" to the .583 you're after. Tell yourself the longer intake runner length is adding torque. Or cut the trumpets shorter. The valley cover could be some 1/8" aluminum plate like the Wildcat design.


Airwreckc
Eric Cumming
RTP, North Carolina
(247 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: LS manifold for Buick 300?
Posted by: Airwreckc
Date: January 29, 2024 05:36PM

Jim B, thanks. I have looked at that new manifold and the only reason I'm thinking about the Rover EFI plenum is the new manifold appears *much* taller, but I don't really have any specific numbers (not having access to either one). Do you have any insight into that? I would really like to fit something under the stock hood without a hood scoop or similar.



Airwreckc
Eric Cumming
RTP, North Carolina
(247 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: LS manifold for Buick 300?
Posted by: Airwreckc
Date: January 29, 2024 05:39PM

Chad thanks--yes one of the things I like about the Rover EFI system is that you can supposedly easily modify the height of it. As I mentioned to Jim B., I'm really trying to stay under the stock hood.



Edited 1 time(s). Last edit at 01/29/2024 05:41PM by Airwreckc.


7sand8s
Dennis Miller

(36 posts)

Registered:
09/21/2008 10:47PM

Main British Car:


Re: LS manifold for Buick 300?
Posted by: 7sand8s
Date: January 30, 2024 08:46PM

Manifold height info:
[www.mgexp.com]
Entry #63


MGBV8
Carl Floyd
Kingsport, TN
(4512 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: LS manifold for Buick 300?
Posted by: MGBV8
Date: January 30, 2024 09:03PM

From Dennis' link above:

Today I went and did an exact measurement using a digital slide caliper and a straight edge setup to measure from the top of the carb flange to the block valley edge. Take in to consideration that the Buick 300 carb is actually beveled with the rear of the carb flange being higher than the front. I took the measurement from the rear of the Buick 300 manifold using a level to make sure I had the exact edge point.

Willpower intake height (with valley plate installed) is 4.00"
Buick 300 original intake is 4.03" tall in the rear.



Airwreckc
Eric Cumming
RTP, North Carolina
(247 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: LS manifold for Buick 300?
Posted by: Airwreckc
Date: January 30, 2024 09:51PM

Carl and Dennis, thanks. Extremely helpful. Appreciate it.


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