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MG MGB GT V8 Factory Originals Technical - Price break down

Well my B-GT still has the 4 banger, and I'm not quite ready to take the V8 plunge yet (maybe in a year when I'm done with college), but I figured I may as well do my homework so I know what to look for and what kind of budget I'll be on. I was curious if anyone had a detailed parts/price break down of their conversion (using the Rover V-8 into a CB car). I'll be doing most of the labor myself when it comes time, so I'm just interested in parts/prices. I figured some one would have a website, or an online list with this info.

Here are my questions about the V8 itself. I love the 4cyl thats in my GT right, now. I like how it revs and sounds, so how does a fairly stock rover V8 rev, and how hard is it to drive in tight twisties?
Secondly does anyone have any info on other 4cyl swaps such as the Ford 2 liter 4cyl? That seems like a good swap, they are cheap, abundant, and lots of upgrades for them.
69 B-GT
Bill Mertz

The aluminum Rover V8 is actually about 40 lbs lighter than the cast iron L4, so you won't need to retune the suspension to get it to ride and handle like stock. I would recommend going to 15" wheels and 195/60 tires to help handle the extra power.

As for costs, it all depends upon how much power you're going after. Remember: the greater the power, the more modifications you'll need to make. A good example is using dual exhausts. You'll need to relocate the gas tank, change the fuel filler pipe on the tank or relocate the aperture in the bodywork. If you really hop up the engine then you'll need wider tires, which means more bodywork. Then there's the changes to stronger axle shafts, probably a limited-slip differential, etc, etc. How much you end up spending can be kept to a minimum by keeping your lust for power in check. A near-stock Rover 3.9L will provide enough power to satisfy anyone who isn't an adrenalin junkie, and the modifications needed to make the conversion safe and practical aren't going to have you living on hot dogs and rice for the next three years.
Steve S.


I recently was quoted a price for rebuilt Rover engines from $1800 for 3.5 to $2500 for 4.2, from Andy Achauer, from Zanesville, OH. I don't know yet what all is included, or the specs of the rebuilds, but am working on it. I can send you this info when I get it, if you want. let me know.

Also, the following sites may be helpful, although I havn't reviewed them lately; I just saved them as links.

Steve W.


Sounds like you should borrow a V8 for a weekend if you can ... as far as revving, etc., it's just a totally different experience. The V8 pulls hard from extremely low rpms -- certainly not much need to "get it up on the cam" before you can tap the power like on a 4-banger -- you'd have to have a really, really exotic cam in the V8 to lose the low end. The Rover V8 has an amount of torque that is simply jaw-dropping to most people who have driven only 4-bangers ... and if you go up to the bigger motors, while there's some revvability lost, the torque is truly amazing ... I've driven a 4.9, and it seems like it could pull over a medium-sized skyscraper! But to be fair, keep in mind that these are just pushrod V8s like the good ole boys drive ... they don't rev like DOHC setups or rotaries, etc. Anyway, the reason people are so crazy about these setups, I think, and willing to devote hundreds of hours to the project, is that these cars are as docile as lambs in town, but the gas pedal is very, very deep and with a flick of the ankle you are simply in another time zone. Passing another car on a two-lane road is almost comical compared to a regular B, a quick blip of the gas and it's over. As far as driving in tight twisties, the V8's wide power band is a huge advantage; you don't find yourself needing to shift nearly so often to keep the power dialed up. There's something primitive yet precise about it. The costly problem for most people, including me, is that once they have driven a decently prepared V8, they have no desire _whatsoever_ to revert to the 4-banger!


I advise you to take time for getting all the bits. Then you may be lucky to get the cheap parts. Rover V8 engines are not very difficult to get over here but 5 speed gearboxes are getting more expensive. A few month ago i was very lucky when a SD1 was brought to a scrap yard when i was there. I asked the scrap yard guys the price for the engine and box. They didn't value it high so they wanted US$ 200,- for it which is a bargain.
at home i opened the engine and found out unmarked oversized pistons were fitted. The heads could do with some work because the cars was driven on LPG. Gearbox was also in perfect shape.
I will use it as a spare engine and box for my V8.
Peter van de Velde

I agree with Peter, plan early, buy long.. Get a list of the main items you need and just keep an eye open for them. Do NOT try to rush, every time I try to set a dealine to be complete, everything falls apart with it. take your time, buy pieces as they appear and before you know it you will have 90% of what you need.
I bought an engine 2 mos after I bought my car, then few months later bought a intake/carb/distrib set-up, 4 mos later I bought a tranny and bellhousing, suddenly I had the main pieces and could start test fitting...

I am doing a 302 conversion and buy buying deals when they appear I am $2300 into it and have less than $1000 to go to be running. I am doing much work myself.
Larry Embrey

How hard is it to get Rover 5-speed gearboxes in the U.S.? I don't know much about their strength or reliability, but at least from a driving point of view, it would be very hard to find a more precise-shifting gearbox. It snicks into place much like the mid-90s Mercedes manual gearboxes. I mean the T-5 and T-56s are fine, but they really don't have that same feel.

Thanks for all the replies guys. I am definitly ready to take the plunge from the mental perspective, it is the finances that have to come together, but that is exactly why I wanted to see a list of the things I need, so I can keep my eyes open. My goal is 200-250 hp, somewhere in that range. I'm already running 205/60 tires with my 4 banger understock body work.
How well do the stock axles hold up to 200hp, are they total junk?
Also I found an XR4TI in the junkyard the other day (this is the American equivalent of the Escort Cos. of the late 80's). Do these 5 speeds bolt up to Rover V8s?

Well you guys have got me excited. If anyone in the Bay Area California has a V8 conversion that they would graciously give me a ride in, I would gladly accept.

Steve, definitly give me the info when you get it.

69 B-GT
Bill Mertz

Bill, the stock axle will hold up fine ... the MGB (tube) rear is way over-engineered ... in fact it has more bearings than a Ford 8". However, you may need to re-gear (except if you use a T-56 trans with .6xx overdrive: in that case you can probably stick with your 3.9 B rear). I had a C 3.07 rear gearset installed in my B pumpkin ... works great with a Rover 5-speed box. No clunking, no whining. Note that my setup runs toward the upper end of your desired power band.

Oh, BTW, one thing that will NOT hold up fine is your driveshaft ... the V8 will make mincemeat of a B shaft in no time at all. Not that this is a big deal; I just thought you'd wanna know.

Bill, I brought over a '78 from SoCA in January and am in the teardown process for a full rebuild/conversion. The following articles are a guideline/goal for my car. I cetainly do not have the $$$ for the Heritage shell or other bits. But, perhaps you'll find them helpful as I have. This car is also showcased in the April issue of Thoroughbred & Classic Cars magazine that may still be offered at the newsstands. I found mine at Barnes & Noble.

Steve, when you have the specs from your contact in Zanesville, will you include me in your list to forward the info? I would really appreciate it. Thanks in advance.
Michael Willis

Bill, if the budget is a big concern you might want to go looking for a Warner T-50. There are I think 3 variations but the best for a low buck swap is the close ratio overdrive which was used in the mid 70's in the Chevy Monza (the V-8 as I recall). It gives you a great stoplight gear with the stock axle and overdrive is very welcome with those gears. It'll hold up to those horses just fine in the lightweight B, and with just a little bending you should be able to get the shifter through the same hole (depending on engine placement). Dan LaGrue (D&D) has bellhousings, etc. Glen Towry also has a full stock of bits and pieces.

According to "Little" Joe Huffaker the stock later model B axle is good for 175 HP, and he should know, as They used to use a lot of MG components in their race machines which were quite competitive. As long as you aren't liquifying rubber too often the axle will do well for a good while but eventually the spiders will start to get loose and the clunking from the driveshaft flange bolts can about drive you bonkers. So plan ahead.
Jim Blackwood

Bill, I guess those links don't work properly. You can get to them though by doing a copy and paste to the Address window.
Michael Willis

Bill go for a V6. The swap can be done in a weekend if you have all the parts.
Bill Guzman

I'd like to try a B with a V6 sometime. I have had no problems whatsoever with my Rover V8, though; that conversion has been pretty well thought out over the years I guess. Is the V6 a pretty torquey motor? ... how does it compare with the BOP/R V8 from a driving point of view? Wouldn't the V6 conversion drastically hurt resale value?

Bill G,
What V6 are you using, and how does the conversion compare with a V8 in terms of price. I would be putting it in my 69 CB GT and still want somewhere between 200-250 hp, and a five speed. If it is cheaper and/or involves less mods and cutting, I would definitly give it a try.
69 B-GT
Bill Mertz

Bill, the swap that I will be doing this summer will cost around $1800 < > for everything.
But it all depends on the cost of the engine and transmission. If new you would be looking at $4500 to $6000. A new 3.4 V6 goes for around $1800 factory new and a rebuilt T5 transmission for about $650.
Plus misc stuff.

Bill Guzman

once you have penciled out everything you can think of regarding cost, take that money and timeline figure times 1.5 if you are an optomist, or 2 if your are a realist and you should be pretty darn close.
todd wyatt

re: V8 revving. I can't say I agree about the V8 not revving as freely as the 4's. My factory car with a Weber on it (no internal mods) absolutely storms up the rev range and flies over the 5200 red line. In fact it's so much of a free revver that I fitted a rev limiter yesterday. Paul H. has the same problem I believe with his Factory car. It's just too easy to get carried away! <VBG>

The only letdown (IMHO) with the factory cars is the gap between 2nd and third. 2nd is great and takes you over 60mph but third lacks ommph and so does 4th. I guess if there's a mod I'd make it'd be going to a 5 speed with better ratios.

Whilst my modified MGA with lightened flywheel and tonnes of other mods will smack 7000, it doesn't get to 5000 as quick as my V8. Over 3000 in 1st or 2nd they assault the redline.

Before I tried a Rover V8 I was expecting it to be like a lot of Aussie straight sixes or V8's I'd driven (ie low great, no top end), even maybe like my MGC but it was nothing like that at all. As others have said, it's hard to go back to a four but they have a different character all together. IMO the best thing about the V8 is driving it daily, it is so easy to. I can putter around in 4th at 20mph-ish and she pulls cleanly with as little as 700rpm on the tach.

Best of luck! If you go for a Rover V8 you won't be disappointed!

74 V8
Neil Cotty

Bill, no need to get tangle with HP #"s Those numbers are for magazines. The number that counts is the torque value that is what it takes to move the mass.
A Chevy 2.8 V6 60 degree engine will develop 170-180 lbs. of torque with a Edelbrock manifold, cam, 390 cfm Holley carb and 11/2 primary tubes, and 2 inch collector headers, add the 2" or 21/4 pipes.
This is only 173 CI This engine is plentiful and inexpensive.
Now 3.4 FI or Carb. Can produce 200 + lbs. of torque.
If you would like to see the actual cost of the project that I will be doing, e-mail, I have a record of the actual cost of all the parts. My time is a write-off as entertainment

Bill Guzman

I found an SD1 for $300 fuel injected and a 5 speed.Problems with FI.Engine will start.So as you see it can be very little.I have also bought 2 TR7 5 speeds for $150 each.Take your time and look around.Good luck.LES.
Les Biglands

This thread was discussed between 14/04/2001 and 25/04/2001

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