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MG MGB GT V8 Factory Originals Technical - v6 -v8 weight difference

my son and i bought a "73 gt and are trying to decide which is easyer to do a v8 or v6 and what is the diff in weight from the 4cyl in it
where do i start for info on this subject and chev, mopar or ford
robert

Robert,

Most people on this list will tell you to forget Ford, Chev and Mopar and tell you to go with a 1960's Buick, Oldsmobile, Pontiac 215 c.i.d. aluminum V8 engine or the more modern equivalent; the Rover V8. These engines weigh about the same as your original 4 cylinder. An early s.b. Chev weights 550 lbs. the s.b. Ford is about 450, but it has a high concentration of weight toward the front. The aluminum 60 degree V6's weigh less than your original set-up but don't develope a great deal of torque and you may be disappointed with the result (could be some argument on this). Some have gone with the 3.8 litre Buick or the 3800 engine from the F bodied GM cars with good results. These engines actually fit the engine bay better than the Rover and have considerably more horsepower and torque, but they do weigh 40 to 80 lbs. more. Much of this weight is shifted toward the rear, so is of little consequence to handling.There is a lot of information in the arc
hives for the Rover installation, so if this is a first time conversion effort for you, that might be the best way to go.

HTH, George B.
George B. Wildomaw

Generally, weight isn't a problem. Most people go with either a
narrow V-6 (Chevy) or a Buick/Rover aluminum V-8. The Ford V-6 as
popular at one time but for some reason has fallen from favor; likely
because they are all getting a little old to find in a wrecking yard.

Anyway, either of these two engines, with its mated transmission
weighs reasonably close to the MGB engine/tranny combo. Any of the other
V-8's is a move into rarely travelled territory, although it has been done. (I put a 302 into an MGA).
These can turn into enormous projects.

The V6 is an order of magnitude easier, the V8 can be an order of magnitude more powerful, if the
engine is modified. (Stock Chevy 3.4 and stock Rover V-8 are both in the 200-250 hp range.)
Arthur Shaffer;Grayson Ky

the easiest is going to be the rover v8 swap as the conversion parts are readily available and everything is a simple bolt in process for teh most part. any other swap requires more time and skill to fabricate the nessacary parts to do the conversion. also when your all done and if you want to sell it in the future the rover v8 will bring a much highr price than a ford a chevy v6 powered one would. most people looking at an mgb would open the hood and see an american v6 and walk away.
cory blackmxz@hotmail.com

Corey,

Rover parts are not that available in the U.S. And if the vehicle is to be sold in the U.S., why would anyone care if it was modified to accept a British engine designed by Buick or an American engine or, for that matter, a Holden engine (designed by Buick)? Modified is modified.

The reason that the MG used the Rover V8 was that British hot-rodders did it first and that the engine was available. The V6 is really much easier to install and gives better weight distribution IMHO.

George B.
George B. Wildomar

There have been some postings here long ago suggesting that some late Chrome Bumper GT's have engine bays similar to the RB cars. If so, and if your 73 is one, the Buick/Rover V8 is probably the easiest project, as all parts are available, and the body modifications are minimal or maybe zero.

If you have a true CB engine compartment, getting the V8 in will require considerable bodywork, steering and radiator alterations, etc.. The Chev 60-degree V6 is an easier fit, is considerably smaller, and is sitting in wrecking yards by the thousands. Against it is total non-originality, and the need for custom fabrication of motor mounts, exhaust system, clutch hydraulics.... In standard production form the Chev (pushrod versions, not the rare DOHC) developed from 135 to 180 BHP. The Buick/Rover V8 from about 150-220. Both engines will present a lot of challenges in the areas of throttle linkage, fuel systems, electrical, etc. Not trying to discourage you - just go in with eyes open.

Might also be good to talk to some experienced MGB people about the kind of power and costs you can expect from a quality rebuild of the 4-cyl!
Bob Wilson

Robert:
Subscribe to the MG V-8 newsletter (check archives for the address). Also purchase the back issues - most conversions listed will use the Buick/Rover motor, but many successful conversions have been done using Ford and GM engines. IMHO the Ford 5.0 liter with aluminium heads, intake, etc. is the way to go. Engines are plentiful in the U.S., weight is manageable, aftermarket and performance goodies are available and competitively priced. Dimensionally, the 5.0 liter is shorter and narrower than the Buick/Rover engine. Your conversion will NOT be worth less if you don't use a Buick/Rover engine (contrary to a comment previously mentioned in this thread), however, be advised that this is an expensive and difficult conversion regardless of what year vehicle you have and most likely you will have more into the car than it is worth. The upside is you will have one helluva screamer when it's done!Good luck.
Mark

I owe a 1973 BGT with a Ford V6 180HP, 1992 Mustang 5 speed. flares, 15x8 wheels with 225.50x15 BFG tires. This car was raced in SCCA EM with a 4 speed. Great combo for all around performance and fun.It is now on the street.
My best suggestion for a convertion is the buick v6 with fuel injection and alloy heads, this engines are light. With minor work they can produce 200 or HP This engines can be found infront wheel drive Buick and Olds. The bolt pattern for the bell housing is the same as the Chev V8 what that means is that you could used GM 4, 5 or 6 speed trans with slave/bearing combo make this swapt simple
The weight is about the same to the V8 with the alloy heads. Used the computer and wiring. for a rear end used a MG 3.07 or for performance use a Ford 8" with 3.55 gears with 23/24 Dia tires. you want to apply the power to the ground 3.90 would spin the tires. have fun Bill G
Bill Guzman Camarillo Ca Bggtv6@aol.com

Bill,

The v6 you speak of, the 3.8? If so, is there a problem being that's a front wheel drive situation...would the same motor from a Firebird or Camero be a cleaner place to start?

Thanks,

Tim
TIm in PIttsburgh

I have a Ford V-6 approx. 200hp from 74 Mustang with a T-5 mustang I adapted. I use 3.55 8inch rear in an Alpine. Performance is great. This would be great for MGB.
TC tc123@worldnet.att.net

If your desire is to go with a V6 the GM 3800 Series II is a good choice. I did this conversion 2 years ago using a 96 Firebird as a donor vehicle. This was in a C/B roadster so the engine bay mods were similar to that of a rover. Unfortunately you have to deal with a different set of problems like a high pressure fuel system, exhaust routing, and computerized controls. With approx 210 HP this provides a very impressive ride.
Don Zeigler

I own a 1973 BGT with a true 180 HPT-5 Trans and 8" rear
The performance is awsome real useable power, would recommend long headers 1 3/8 primaries X 36" long with a
2 1/2 collector, headers are not available for this swap you must fabricate the tubes should go upwards (Mopar style) to clear the steering. I really enjoy my GT it has flares to house 15x8 wheels with 225.50x15 BFG tires
Oil pan makes a difference for the installation you will have to used the rear sump oil pan and a hood scoop to clear the carb.
Bill Guzman Bggtv6@aol.com

I have a Holden Calais a supercharged GM3800 V6. This could be a real hot item for a MGB conversion. Out of the box this has ~235bhp and easily tuned for more, the low down torque is incredible.
David

Tim,
the egines are the same, the difference is that one has tune-port injection and the Camero/Firebird does not
only the new ones, you have to be carful becouse the engine also comes in 3.0 and 3.1 the 3.8 can be identified by the air cover, the cover is stamped 3.8 over the engine and the price at Pick-Apart is around $175 plus the harness $50The only mods the engine needs, is a good cam from crane, adjustable fuel regulator, and a Chip from Htpertech and the stock manifolds without the converter. Lots of torque.
Bill
Bill Guzman Bggtv6@aol.com

Apples and Oranges, gents! Two completely different engine families being discussed here.

The "2.8/3.1/3.4" engines which have appeared in front and rear drive applications of various GM cars are made by GM's Chevrolet division, were designed as V6's right on the drawing board, and use a 60 degree bank angle. The engines are quite compact and lightweight, although only the front-drive versions were ever produced with aluminum heads. The highest BHP in rear-drive form was the 3.4-litre available in F-bodies (Camaro/Firebird) from about 1992 to 1995-1/2 at 160BHP. (Leftover units are available from GM as a "crate motor", complete sans carb/FI, ignition, and manifolds.)

Midway through the '95 model, GM changed the F-bodies to the "3800Series" V6 which started life as the old 3.8-litre Buick econo engine for many mid-size GM brands in the late 70's. This basic design originated as a V8, and they chopped the two middle cylinders out as a cost-effective way of producing a "new" smaller displacement economy engine in the gas crisis days. This unit has been extensively developed over the 20+ years and is now a nice motor. But it is a 90-degree bank angle, and thus considerably wider and a bit heavier than the Chev. Someone here indicated that it has aluminum heads; I don't believe so... but invite correction. In a CB car, I would expect that it would have the same steering column and bulkhead clearance hassles as a V8....but Don Zeigler is the one with hands on knowledge and perhaps could comment.

As a modern (no more than four years old) and very sophisticated engine, not to mention the relative rarity of the donor cars so equippped, I would doubt that it could be found in wrecking yards at bargain prices. However, if the big Holdens are being smashed up at an enthusiastic rate in Oz, their version of this engine may be more readily available.
Bob Wilson

Bob is correct that the 3800 Series II does not have
aluminum heads and being a 90 degree engine requires
an additional "U" joint in the steering column. Also
the exhaust is routed out the inner wings. Unfortunately
the headers had to be custom built because like Bob says this engine has only been available in this configuration for a short time. Therefore very few aftermarket parts are available.
Don Zeigler

Bob W. Here in the US we have the Buick 3.0-3.1-3.8
what you refering to is the 60 degree Chev. 2.8-3.1
The latter were install on the Cameros etc...
The 90 degree engines until 1987 or later were used on the Buicks and Olds. And yes you car purchase a 3.1 60 degree from the chev. dealer which is advertise as a upgrade for the 2.8 it has 155/70 hores. Also in the 1982 we had a car call Citation HO equiped with a 2.8 155 horeses the same engine went into the 1985 fiero with tune port injection rated at 175? < > Horses great engine for a swapt it looks great on a MGA. enough of this stuff.

Bill
Bill Guzman Camarillo Ca. Bggtv6@aol.com

Bill - fair enough...thanks for the info about the other 90-deg Buicks.

One thing folks need to keep in mind is that about 9 out of 10 of these engines in the yards are from FWD vehicles (ie:transverse orientation), and have application-specific castings with starter location, motor mounts, bell housings, intake and cooling plumbing which will add to the problems of fitting them in a RWD setup.
Anyone considering one of these as a swap candidate should make sure the engine is the RWD unit.
Bob Wilson

Bob, The castings on the front wheel cars equiped with V6 90 Degree and 60 degree share the same Bell housing as the 350 chev. At the present we are installing a 3.8 Buick tune port injection in a 240 Z Datzun (sorry) And install a 2.8 60 degree on a MGA (very easy swapt) that came from a Chev Citation the differeces are in the intake manifolds, distributor on the Chev, yes! the motor mounts are different but the casting on the block are the same, so would used RWD motor mounts, and Bob you are right the Starter location is diferent on some models but the block is drill for either side. GM use one Block for both models, (Economics)with the exception of second generation V6
60 degree Alloy heads, that engine was especific for the chev corsica etc...
Bob, you are very know your engines, I would relly like to chat with you and share ideas.
r/ Bill G.
Bill Guzman Bggtv6@aol.com

This thread was discussed between 10/09/1999 and 30/09/1999

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