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MG MGB GT V8 Factory Originals Technical - mgb v8 bonnet clearence

I am converting my mgb to v8 power all the engine and box are in along with many other items.
I have an offenhauser 360 manifold/carter 4 barrel carb and a 3 inch holley airfilter.
It all looks the biz but its sits to high for the standard bonnet to shut. I could cut down the bottom of the filter casing which gives me 3/4 inch but it is brand new, I could change the top nut and bring it down 1/2 inch I could cut down the element!!! Would a holley be thinner in width ? It does not hit the cross member either.The obvious choice would be a bulged bonnet but I hve no idea where to get one and money is tight.
Help please . Regards Paul
p stanford

Here is a pic of my V8 Gt. I made a fibreglass mould for the bulge. You can borrow it if you like and make your own. Made to fit a "C" bonnet.



Oops forgot to add the link to the pic.¤t=combe.jpg


I assume drop base filter and should fit under RV8 bonnet.

cheers for the reply.
I reconise the car you took me out in it when I bought the diff gears(still haven't got them fitted!!)
Maybe a fibreglass bonet with a bulge in it might be easier. Any idea where I may get one? heers Paul

I have the offenhauser manifold (I think it was a 5160)and a holley double-pumper on my 3.5L Rover. I used Glenn towery's ac mounts that made the engine sit back closer to the firewall. I also used a corvette style aircleaner that drops down around the bowls. Its a reproduction part for like the corvette LT1. eBay always has them. I bet if you get this aircleaner, it will give you the clearance.

Her is an eBay link to one. ANd they are all about this price.

You can see my car with the rover v8 as well as a bunch more at

There is absolutely no reason to cut the hood. (Don't do it).

Richard Morris
Richard Morris

You might try an off-set air filter base. The one I have is made by Mr Gasket. It's intended application is for small block Chevy with the large HEI dist. I just rotate it so the off-set portion is to the rear, where there is more hood clearance.
I believe the Carter carb is approx 1/4" shorter then the Holley 390.
bill jacobson

Hey Paul
Didnt realise it was you!
If you use the drop base filter with a 2inch element it should fit under a "c" or RV8 bonnet.
Try Smith and deakin
or Honeybourne mouldings

Good luck


I had a look on the Honeybourne site 86 for a RV8 fibreglass bonnet.
I will have one next month !!!
Thanks Mark.
Kindest regards Paul
p stanford

I'm using an Offy dual port manifold, 365 Holley, 14" lowrider filter with a 2" element, standard engine mounts & it all fits under a standard '71 hood/bonnet easily, as long as the reinforcement strip under the hood is moved forward a couple of inches. Barrie E
Barrie Egerton

Here's a link to my car to give you an idea of what I did to get the filter to fit:

I'm using a 1.5" drop-base with a 1 7/8" K&N filter (K&N finally came out with one shorter than 2") and the "Extreme" top. The 3.5 Rover rides on the stock '77 mounts and the hood cross-brace was notched but not moved.

Edelbrock carb and intake. No changes to either.
Simon Austin

some great pictures .
I am looking at a costello/rv8 fibreglass bonnet when I have some cash.The only thing can think of lads is that the 360 manifold makes it all sit a little high as the engine mounts are standard with the adaptor brackets.
Cheers to all I think a ulged bonnet is easier than changing the manifold (again).
Regards Paul
Happy new year
p stanford

Thanks Paul. I have to thank Curtis for posting them on his site. Makes it easier to show than me trying to send out a bunch of pics.

IIRC, the Offenhauser intake is a bit shorter than the Edelbrock so you may get away without any hood mods. When it comes to getting these engines to fit under the hood, every 1/8" helps. With that in mind, I personally like the "bulged" hood, whether it's the Costello or the RV8.

Happy 2007 to all and safe motoring!
Simon Austin

Hi Paul

I have a Webber carb kit which is the Edlebrock manifold, webber carb & 2" Low rider air filter fitted to my V8B. This clears the standard B bonnet by about 4-5mm - close but enough!

I have had to remove the centre cross brace from the bonnet to give this clearance. I was advised to re-locate this brace further forward, but found that this wasn't necessary.It may be necessary if you have an aluminium bonnet, but is fine with the steel one.

When I did my conversion I found Dave Vale of the V8 Conversion Company in Farnborough, Kent to be very knowledgeable & very helpful.
Ian Tapner

Edelbrock/Webber/Carter carb is shorter than the Holley.

Edelberock manifold is shorter than the Offy, Buick/Olds factory 215 intake is the shortest of all. Buy one from Glenn Towery, D & D, or E-bay. No lack of performance up to around 5000 rpm. If you run faster than that on a regular basis, use the aftermarket stuff.

Set the engine back with either Glenn's or D & D's mount adapters. Lower the engine with any mounts with a long stout rod and a BFH. After the drive train is in place, loosen the nut below the frame mount and hammer on the lower steel plate on the rubber biscuit. This will compress the biscuit and prolong its life and lower the engine from 1/8 to 1/2". Remove any unnecessary shims.

Jim Stuart

I have a JWR Dual Port Manifold with a Webber 500 carb and 2" Mr Gasket filter, + Cast MGB V8 cover.
I removed the bonnet crossmember and have about 15mm clearance. I fitted plates where the bonnet crossmember was for strength.
I could not lower the engine as I have power steering and fitted the twin gas bonnet supports so the bonnet would not twist.
D M Tetlow

I am rebuilding a 65 MGB that I have had since 76. I've waited 23 years to start the project. I am looking for as many ideas that I can find regarding body modifications, (i.e., Sebring fittings, etc.). While I want to keep the look as original as I can, I am searching for the right Sebring look. I will be increasing the size of the engine to 1950cc and adding a Super Charger from MOSS. MG Limited in Milwaukee will be doing the work for me. Any ideas out there for some cool add ons.



Lots of engine conversions with body mods and descriptions at the site below.

(mine intentionally looks as stock as possible and hides the V8 well ;>)

Good luck,
Edd Weninger


as Dave allredy mentioned the JWR inlet is a good step forward as it is the one that leaves most under bonnet space for a carb and filter.

The flattest 4 bbl carb is the Carter 400, if you can pick one. Edelbrook and Holley are nearly equal in hight, although the Holley is less comfortable to set up.

You should allways keep in mind that a 4 bbl carb should have at least 2'' free room above the airhorn as it looses power otherwise!


I have ordered aRV8 fibreglass bonnet for 85 this should give me the most room with the least mods I needed a new bonnet any way as my aluminum bonnet has seen better days,
thanks to all especially Mark from Wiltshire with the 300bhp GT,the quickest mg I have ever seen!!!
Still haven't fitted those diff gears but I will.
Cheers Paul
p stanford

Thanks Paul
Just remember that the drop base filters will restrict airflow. Not an issue unless you start tuning for more power.
How close are you to finishing the coversion?
Mine has grown flared rear arches and wider wheels/tyres along with a foam filled petrol tank.
You are most welcome to come and have a proper ride at the Sports and performance car action day at Castle Combe on 21st April. If your car is finished it might be a good run for it.



This thread was discussed between 30/12/2006 and 17/01/2007

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