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MG MGB GT V8 Factory Originals Technical - Headers/ fender bashing

Is it neccesary to 'dress' the inner fenders on a chrome bumper car to accept headers or is it required only when using block huggers? I read one post by someone who stated that he had to do a little bashing on his '77 to get headers purchased from Towery to work properly. Are all headers created equal? Where is the best place to purchase headers in the States that work well with the least amount of work to the inner fenders?

Yes, you have to dress the inner fenders, even if they are blockhuggers. I also have a 77 RB and used the blockhuggers from Towery. Too bad I didn't know it beforehand bacause the engine was already in place when the huggers arrived. I had to hammer back the fenders as much as I could. This winter I will take the engine out of the car to do a full body restoration. At that time I will dress up the fenders. Cut a longitudinal slit and hammer both ends together to take the bulge out.
hope this helps you not making the same mistake. Let me know if you need more info.
werner Van Clapdurp

Related question: I have block-huggers and I am told the RV8-style headers can make a _big_ difference in power, as well as cooling of course ... the engine bay was nicely dressed to accommodate the block-huggers, and then properly painted ... I'd hate to screw it up ... can I just cut the holes and hook up the RV8-style with a minimum of hassle? The car (CB) is set up conventionally; the motor is in the standard V8 position, etc.

I am in the process of replacing my existing 215 & block huggers with a Rover & RV8 headers. The block huggers required a little extra clearance at the sharp corner where the recessed part of the inner fender returns just above the frame rail. I drove the convex corner in with a hammer about 3/4" deep. It did not require any cutting. I originally used Glen Towery's block huggers which lasted 12 or 13 years although I had to repair several splits. These headers used individual flanges. About two years ago I replaced them with a set from TSI Automotive using continuous flanges. The fit in the engine bay was the same but they required a heavy clearance cut for the dipstick. I understand the continuous flange style may be less prone to cracking.

I just finished cutting the holes for the RV8 headers for my current conversion. I bought RV8 reinforcing panels from Brown & Gammons to help locate the holes. These also showed the amount of relief I had done for the block huggers. The left side cutout for RV8 headers is significantly longer than the right. With luck I should be fitting the engine in the next day or so and will know how things fit.

Joe Collins

Joe, is your car rubber bumper or chrome?

Maybe not.

My '79 MGB V8 has block huggers and the A/C stlye engine mounts that place the engine a bit lower & back. The headers are very, very close, but I didn't do any clearancing of the inner fenders.


My car is a '77 rubber bumper. The original motor mounts used a position a little forward of what seems to be common now. Besides operating clearance, the fender bashing allowed the headers to be removed without breaking the mounts loose.

Joe Collins

I've just fitted RV8 style headers, they seem to exit very close to the flexible brake pipes, have you re-routed them?

Mike Barnfather
Michael barnfather


I am using the RV8 front suspension which has plenty of clearance. I would have had to move the brake pipe to flex line fitting had I kept the stock front end. I had already replaced the tube shock conversion with original levers for clearance before deciding on the RV8 suspension. I just fitted the steering rack tonight and there is plenty of clearance unlike the block hugger setup.

Joe Collins

I used blockhugger headers from "London Stainless Exhaust" in england and required no dressing of the inner fenders in my '75 B. I have since changed to stainless RV8 headers. The right hole islocated further back than the right because the head is but appear almost equal in size. The header can not be installed with the engine in situ.
Keith Childs

do you get any sort of template or diagam with the RV8 headers so the inner wing holes can be cut accurately??Or do you have to measure it all out as best you can??


John, There is no template. Start small and keep trimming till it fits. I made the openings much larger to allow installation of headers with engine in but I didn't like that. I mig welded plates like the RV8 uses to the hole.


I used the RV8 reinforcers referred to above as templates for my RB shell modification. They are still manufactured by Heritage so any authorised dealer should be able to get them.

I imagine chrome bumper shells may be different.

This thread was discussed between 05/11/2001 and 30/11/2001

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