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MG MGB GT V8 Factory Originals Technical - HORSE POWER QUESTION

I am planning on converting my 66B and I think that I want about a mild road engine rated at about 200hp the question is which ROVER would most easily achieve this rating?
Bill Mendels

Put a real engine on your B, Ford or a Chevy.
Karl Hemmings

Bill, a 3.9 or 4.2 should fill the bill pretty easily. With even mild tweaking you'll be at or above your target horsepower. Personally I like the 4.2 -- has a bit more low-end torque -- but a lot of smart people like the 3.9 as it revs a tad more freely.
Fred

Go for a fully balanced 3.9 with a 390 double pumper Holley and some head work, plus tubular headers and electronic ignition.
Bob
robert pulleyblank

Why you would ever put a double pumper Holley on a Rover V8 sure is beyond me. The carbs of choice, if you decide to go the carburetion route, in order of preference, IMHO are (i) a Carter 400 (i.e. model #9410), (ii) a regular Holley 390 4-bbl, (iii) a Holley 450, if you can do without a choke (it's a race carb) or (iv) an Edelbrock 500. Having tried all sorts of different carbs, it's my opinion that the Carter is simply the ideal unit for the 3.9/4.2, whether or not it's been hopped up somewhat. That being said, a good one is mighty expensive these days, I am sorry to report.
Ted

The reason I have a double pumper on my 3.5 litre roadster conversion is because one was readily available when I built the car.This gives 200 hp at 5500 rpm at the wheels on Sigma Engineering rolling road. My 3.9 "factory" GT has a 600 double pumper, and barely run, in gives 215 at the wheels on the same rolling road. I have also done a back to back test with a 390 vacuum. 390 double pumper and the 600 double pumper on the 3.5 litre and believe it or not the 600 gave the best top end with no losses lower down. The vaccuum carb had a flat spot. The ONLY way to compare carbs is on a dyno, and equally important on the road.
I should probably have tried the 450 mechanical had I known of its existence back then as they are cheap. Again the Carter was out of production and the Weber/Edelbrock was not available back then.
Sigma Engineering who prepare all kinds of racing Jaguars do not like the Edelbrock because of its metering rods. I have a brand new 600 vaccuum secondary with the choke removed, quick change acccelerator pump unit, and a secondary metering block fitted if any one is interested. I guess it is a 4150 after the mod. You do not need a choke on any Holley equipped car in England in my experience. 150 pounds will buy the 600!
robert pulleyblank

This thread was discussed between 27/12/2000 and 29/12/2000

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