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MG MGB GT V8 Factory Originals Technical - Source of 4-choke carb bits

Hi folks,

I have a 1978 MGBGT fitted with a Rover 3.5 V8 engine. Currently I am using SU HS6 carburettors and a Rover P5B air filter assembly all mounted on a Rover P5B inlet manifold. I am considering changing to an American 4-choke carburettor and associated inlet manifold and air filter assembly. The current pound/dollar ratio seems to indicate that it might be a good time to purchase these items from an American source rather than buy them in the UK.

Current perceived wisdom in the UK suggests an Offenhauser Dual Plane manifold upon which an Edelbrock 1404 carburettor is mounted and topped off with a Mr Gasket Low Rider air filter.

Firstly, is this a sensible combination for a road-use car?

Secondly, I am having difficulty identifying the part number of the Offenhauser manifold. I want to be quite certain that Im buying the right one returning it to the US is not an attractive option. Any advice would be welcome; I need the lowest manifold I can obtain.

Thirdly, from UK information, I understand that a specific thermostat housing is required to fit the Offenhauser inlet manifold. This would be to have the inlet pipe pointing forward to connect to the right hand side when viewed from the drivers seat of the radiator top tank. At first sight that would seem to be similar to the Rover manifold. Any advice would again be welcome; maybe the Offenhauser manifold comes with a suitable thermostat housing but I cannot find out.

Fourthly, would the manual choke version of the Edelbrock carb the 1404 model be the best for road use. Im not sure about electric chokes and, anyway, I already have a hole in the dash for a manual choke cable! Thoughts again, please.

Fifthly, can I buy a Low Rider air filter without a paper filter element? Id like to use a K&N filter from day 1.

Finally, I can buy these parts from Summit Racing. Can anybody tell me, are they good suppliers or just a well-known supply company? Are there any better suppliers?


P L Hills

My first recommendation would be to look at D&D's website, review their parts catalogue, and then give them a call - they are the best at suggesting rebuild information.
Dan and Mark know these engines inside and out and offer a multitude of components. You might find that the original BOP 4bbl manifold has the lowest height and good low end performance.
Graham Crteswick


Thank you. An interesting site. I didn't know that the original BOP inlet manifold was still available commercially.

P L Hills

The original Buick 4 barrel manifold is an excellent choice. They are no longer made, but come up for sale frequently on ebay. Here is one that might go cheaply..
The best carb for this set-up is the 400cfm Carter 9400, but these are rare. best of luck...cj
C. Jones

C. Jones, Utah

Please e-mail me off line.


Al Wulf

Al Wulf

Peter, The Buick intake is a good way to go but make sure you get one that's had all of the old bolts removed. You could end up with siezed/broken bolts that will give you headaches. Remember,they're 45 years old.
I run a Buick 4bl manifold and the Carter 400 on my 4.0 and it works well.

Kelly Combes


there is an other intersting inlet offered by John Wolfy Racing in the UK. It was designed for the Rover V8 engine as a dual plane version and is the lowes inlet ever made.

On my V8 i have tried the normal Rover inlet, the Buick version and ended with the JWR, tried the Edelbrock Performer and refitted the JWR again. Using a Holley 390 (Edelbrock did not offer these cabrs in the eraly 1980's when i did the conversion)the JWR manifold gives more torque and better distribution but has it's limits in top speed. As i never was willing to try more than 135 MpH with my car, this does not harm anyway and who wants to reeve a V8 in a B at 6.500 RpM?


These two cotton gauze type air filter elements fit the Mr. Gasket low profile air filter. I have the Summit element works great.

K&N Air Filter E-3740 14"x2"

Jim Miller

This thread was discussed between 21/04/2007 and 02/05/2007

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