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MG MGB GT V8 Factory Originals Technical - RV 8 headers

Hi All,
Does anyone have the "template" for the holes I need to cut into the inner wings of my B for the RV 8 headers to go through?
Is mthere anyone who sells the "strengthener" that should be welded around the hole in the inner wing?
Tony Bates

It's my feeling that engine placement varies slightly, so that the openings have to be 'custom'. I started small, from the center of the downpipe, then opened it up little by little until the header could be unbolted and removed with the engine in place. The openings will probably be larger than you expect. I formed a removeable plate, secured with srainless screws, to cover the upper area of the opening, providing some protection from water and making for a more finished look. I can't claim that idea; I first saw that on Bill Jacobson's car at the Bellevue field meet last year. Regarding the 'strengthener', out of 11 V8s that I saw at that show, 10 had RV8 headers, and 8 had no reinforcement of any kind around the openings. One of the leading V8 convertors that I spoke to on the subject doesn't use any either. Sorry, I didn't keep the templates, as I found them useful as a general guide only; the openings still had to be enlarged somewhat to remove the headers from the engine bay.

Best, Joe
Joe Ullman

Brown & Gammons in the UK was selling those strengthening a while back. Maybe still.

When I got to that stage of my conversion, I had the engine in car bolted down without the headers.

Through trial and error (more trial than error, thankfully) I just lowered the headers down to the inner fender and as Joe states, started with a small hole through which the down-pipe passed and then gradually enlarged the hole until the header was lined up with the exhause ports.

I think I left no more than an inch around the pipes and will now clean up the opening and add a removable plate if required.

In order to keep the heat from the header to a minimum and keep the paint from been affected, I just had the headers ceramic- coated. Supposed to reduce heat immensely (at least according to the guy that did them. I'll find out in due course).

Simon Austin

As Joe says, engine placement varies. Also cutting out a pair of strengthening rings seemed to me a lot of work with lots of potential for a very messy finished job re: welding them in. I had a look at a set of RV8 "strengthening rings" (on an RV8) they didn't look to strong anyway, seemed to be less than 2mm. (Clive wheatly also sells them.)
Instead I went around the edge of the holes with a small shifter and turned done the edge about 1 cm. The metal is very soft and if you use a couple of pieces of carpet (or rubber) you can do this neatly.
This turned out to be surprisingly successful. It is very stiff (no discernable movement) and it looks very neat and tidy with its rounded edge. I also (probably unnecessary) put some filler into the back of the "turndown".
My holes ended up larger than usual (by 2cm!) as the turndown approach was a last minute decision however I have no fears about weakening the car as any tension force is taken by the rail and the compressive force is being easily handled by the complex upper guard/boxsection/outerguard structure. The bit in the middle doesn't do much. Also having read of the many cooling benefits of increased engine compartment air flow through I felt that this was a plus.
I have recently thought that attaching a slightly larger (than the extractor guard hole) stainless splashguard to the extractor about an inch below/outside the actual guard hole might not be a bad approach. That way I could keep the benefits of airflow with out the disadvantages.

Simon - I have had a previous exhaust system for a Lotus Seven Cosworth ceramic plated and the end result was great. It has kept it's "shine" and definately is cooler than before.
Peter - In the 4th line of your note your refer to a "small shifter", what is it? Is it an ozzy term like "tinny" is for a beer?
Tony Bates


I think you guys call shifters (adjustable spanner) monkey wrentches. The is probably a special "edge rounding tool" you can get
Alas the tinny is now becomeing passť, "stubbies" (short and stubby bottles) are becoming very popular as there is less chance of physical injury from getting your nose caught on the sharpe metal opener, (remember we like our beer strong).
Infact I think I'll go sink one right now.

Peter of Melbourne, you should check with your local registration auth. or a certified engineer about the lack of a reinforcing plate. You'd need one in NSW according to the NSW engineering guidelines for converted/altered cars.I think the size of the hole comes into the formula. Good luck, Barrie E
Barrie Egerton

Whitworths (the marine and boating places)sell a vent for cabin ventilation which may be suitable for what you need.
Chrome plated brass and measures about 4 x 7" from memory and has three or four louvres.
More importantly though it has flanges both sides and is surprisingly cheap as well.
Worth a look,
Cheers, Pete.
Peter Thomas

I don't believe I need reinforcing here in Victoria as I've seen some conversions at MG workshops with Huge square holes and no reinforcing at all but thanks for the heads up, afterall I may be moving to Sydney some time in the future. It would be nice to live somewhere where it doesn't rain constantly.
I like the idea about using marine gear. When I'm not limbo danceing about under MG's I'm usually sailing boats. Hadn't made the obvious connection though.
There should be a large variety of Portholes vents stainless or chrome and would look very nice. Good idea!

I have some templates that I got from the MG Owners Club when I bought the strengtheners. You could either contact then Direct or I could reduce my templates to half size, scan and email.

Andrew Hamilton

<<I think you guys call shifters (adjustable spanner) monkey wrenches>>

Adjustable wrench, Crescent wrench (brand name), also known 'round these parts as a "Hillbilly socket set".:)

Hi Andrew,
If it's not too much trouble, could you reduce your templates to half size, scan and email them to me?
Tony Bates

Hi Tony,

I fitted the headers to my 1973 built converted car two years ago.
Starting with drawing the dimensions to the inner
wings after some mesurement.
It took me one weekend to have it cut away with the
necessary clearence to the panels.
You can only customise it to your car as the mounting
position of the engines are not allways equal.
The result is very ok and looks stock. It also helps
to have a better ventilation in the engine cimpartment.
Much success!
Greetings from Germany
Ralph Siebenhaar

OK, thanks all, I now understand what's involved in fitting them, heres a couple more questions.
What size primary's 1 1/2", 1 5/8" etc for a 4.2 L rover
Stainless or mild steel, assumimg they will be ceramic coated?
Tony Bates

4.2 works well with 1 1/2" primaries. I have run a 4.2 for several years with this set up. On the recommendation of my engine builder, I am using 1 5/8" on a 5L for my next car.
Jim Stuart

This thread was discussed between 31/12/2002 and 03/01/2003

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