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MG MGB GT V8 Factory Originals Technical - To hug or not to hug?

I have to start buying parts for my new V8 and
would like to know the advantages/disadvantages
of the Hugger style headers and the RV-8 style...
From what I understand the Hugger gives less HP
but don't require cutting the inner fenders...
What are your opinions/recommendations??

TNK Keith


I went the RV8 route and have no regrets. Cutting the holes isn't a big deal. I like to think because the headers sit away from the block and there are new holes for hot air to exit the engine bay, the 3.5 runs a lot cooler.

Only got 1000 miles on the car since completion and so far haven't had any cooling issues. Twin MGB electric fans and an extra tall rad seem to help as well.

Looking at how tight things are along the frame rails I can't imagine how the block-huggers actually fit down there. I've read that the original BH's weren't the finest quality nor do I know if they're available new now.

Contact me if you'd like to see some photos of the headers.

Simon Austin

Block Huggers are crazy. they restrict power, keep lots of hot air in the engine bay, and have a propensity to crack. Cut the fenders, you won't regret it.

TNK Keith
I have block hugger headers, bought from one of the popular V8 dealers. So far (5 years driving my Rover 3.5 conversion ) they havenít cracked. But I remember when I was researching this project, that someone from this BBS suggested it might be a problem later in their life. Probably nothing welding canít solve. And everything does have a certain time expectancy
Are they hotter? I am sure they are. There is certainly more pipe area in the engine compartment. But they are ceramic coated and cool to the touch in 10 minutes. (And yes they can be welded over the ceramic coating). I would also suggest they make pulling the engine a harder task.
For the first couple of driving seasons I did experience some cooling problems, even with a new Ford Falcon Rad. I solved the cooling issues by installing ductwork to force all available air through the ST Front valance and through the lower part of the rad. I also installed louvers high up on the engine bay side walls to get rid of the heat into the low pressure wheel wells. So far this set up has stood up to 100+ F temperatures. (Highway driving).
I donít know about restricting power, I drag race mine and I sure have surprized a few other racers.
For me, when I started this project I had a vision in my head of what I wanted my engine conversion to look like. It probably cost me more money and caused me some problems, but I am really happy with the result.

Bruce Mills
Bruce Mills

The RV8 style keep the engine compartment ALOT cooler. I read all the comments about over heating in the archives and went a little over the top by installing a very large aluminum radiator with a single huge fan behind it. With the "through the guards style" exhaust it is very apparent that this was not necessary. I've since seen that the electric fan on the RV8 is actually quite small and the radiator nothing special. All the problems with the MGV8's over heating devolve from the air coming through the radiator into the engine compartment then not being able to get out again. A kind of air dam forms.
The wheel arches are a low pressure area when the car is moving and actually suck air from the engine compartment. On hot summer days you can actually see the shimmer of heat pouring out through the wheel arches! I've never had any problem with splashing up through these appetures in the guards because of this air flow, even when driving relatively slowly on a muddy gravel roads up though the mountains.
The other big advantage is that the rovers (even the range rovers) often have trouble with the starter motor overheating due to exhaust proximity. In the MG the exhaust is jammed between the engine mount and right up behind the starter and even with a heat shield can be a problem.
As Justin says there is also the power output aspect. I've read variously that you gain between 10 to 13 BHP with the RV8 style. That alone is pretty compelling.
The only reason you would use block huggers is for personal asthetic reasons (and that is as a valid reason as any) however I personally happen to think that the RV8 headers in place look pretty damn impressive and dramatic.
The are two down sides, the RV8 style exhausts are more expensive and of course there is the personal trauma of cutting big holes in your favourite car. I doesn't appear to weaken the car at all. Infact I've seen alot cars where they didn't bother to reinforce the edges of the holes, although I've seem some put a piece of trim around the edges. I went around the edge and turned it down(belled it) which looks quite good and is very ridgid/strengening. I cut the holes with a angle grinder from the wheel side but when I do the next one I'll just use a drill and a hacksaw blade as the metal is quite soft and easy to cut.

good advice alround - a couple of extra thoughts; the starters tend to develop heat related problems with the blockhuggers (and are a bugger to change) - the cast (pig) iron huggers are difficult to come by now but they are quieter than the tubulars - ceramic coating certainly reduces some of the the heat and the MGB is indeed strong so that you can easily cut louvres in the inner wing to help disperse heat without fear of cracking or distortion.

Roger (seen the film - got the teeshirt)


Re starter.
Again with any problem there is probably a solution. And even more so with cars if you are willing to through money at it. I solved the starter problem by buying one of these mini hi-tork starters from D&D. Much smaller than the Rover so it doesn't need a heat shield
I had to remove the starter last winter to tighten up a solenoid bolt. It took about 20 minutes to do the job with the tubular headers/engine in the car.

Bruce Mills

Having used the original Cast huggers then stainless huggers and now RV8, my advice is


I built a set of equal length headers that fit in the space between the block and the frame rails. They are 38" 1-3/8" primaries into 2" dual exhausts. I haven't run these yet, they do prove that you can fit real headers in without cutting up your car.
Chris J.

Yes, if you have the highly developed skill, or big money to get someone to who does. Given the choice between huggers and RV8 style, the access through the inner fenders has it's advantages, and no real downside. I didn't hug, either. Joe
Joe Ullman

Anyone post pictures of the RV8 setup in an MGB? -G.
Glenn G

Send me your email address and I'll send some.

Kelly Combes

Saw a set of the headers offered by Coyote racing. They looked VERY good! The price is cheap for such a limited production item. As far as I am concerned, the headers (or lack thereof) were the last reason for doing a 215 rather than a 302 in North America.


This thread was discussed between 08/06/2005 and 14/06/2005

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