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MG MGB GT V8 Factory Originals Technical - Any LS1 conversions yet?

The miata people seem to like this engine swap. Other than being an ugly looking thing, I figure if it will go into a miata it should go in a B. The engine block is aluminum as a bonus. Anyone actually put a tape to one of these?


Hi Pete
This comes close but the site hasn't been updates for a while: The builder is doing a pretty radical job on the shell; I expect a more standard-looking body could be used if preferred.
Nick Bentley

i sold a gt shell to a local fellow that is having ted at fast cars do this conversion to i believe, i saw the owner about a month ago and he said he expected to have the car for next summer, maybe someone in MI has pictures? jim
james madson


I have seen the site. Too bad the project is abandoned or just not updated. From what I can tell, the engine is failry compact and rear sumped. No idea of how wide or tall it is, only that it fits under the hood of a Miata. It can be bolted to a T% with a bit of work or used with a six speed. Cost would also enter into the pic, but power per dollar, it is still a good value.


How about a LT1 conversion? Predecessor to the LS1.

E-mail me if you have questions. Been a while since the shop has worked on the car despite them having money to work with. My father and I are considering moving the car to a different shop.


How close dimensionally is the LT1 to the LS1?What got me started on this thread was the belief that the LS1 might be smaller dimensionally than the "old" small block.

I want to say that they are both 60 degree blocks, but I am not positive. The LS1 may be a little shorter due to the manifold changes.
I would have prefered a LS1 for my MG, but the LT1 was much less expensive. It only weighs like 150lbs more than a MGB engine.
To me the bonus to the LT1 was that it used standard SBC parts excpet for the heads and manifolds. Beware, the LT1 uses special narrow piston rings(on the stock pistons) and is specialy balanced. So you can't just swap a standard 350 crank into a LT1 with stock LT1 rods and pistons.
But a standard 383 or 396 stoker kit will fit the LT1 as easily and as successfuly as a Gen 1 small block.

How about a LT5 conversion? Anybody seen such a conversion or planning to build it? That would be a stunning combination...


LT5 would be stunning- and obscenely expensive. The last LT5 I saw for sale was in the range of $12,000! This engine shares only the letters LT in common with the LT1 and LT4 engines.
Pretty engine, but I would rather get a hold of a LS2 or LS6 as far as price and replacement parts are concerned.

LS1 engine measures approximately 25.25" long (Rover V8 is 27.5"), LS1 overall height is 24-25" (Rover V8 is 25.5" plus the carb and air filter or efi plenum, 29-30" or more), LS1 width across the cylinder heads is 20.5" (Rover V8 is 20"). With the T56 6 speed gearbox fitted the LS1 is some 3" shorter than a Rover V8 with a standard 5 speed gearbox


I think you mean to say that they are both 90 degree engines.

The LS6 designation is as confusing as the new MG TF. In the good ol' days an LS6 was a hi-po 454 big block.
Carl Floyd


Ok, so fess up, if you have THAT much info, you must be into this swap by now!? It would seem from your measurements that the LS1 should be the engine of choice for the conversion. So other than cost, what are the downsides to this combo?


Right Carl- 90 degrees was in my head and 60 left my hand.
The LT-1 was also a high performance small block of the 70s.

Any one know the weight of the LS1/ LS6 engines?

total dressed engine weight (2001)
LS1 auto 457.6 lbs (208kg)
manual 497.2 lbs (226kg)
LS6 497.2 lbs

Anyone serious about this conversion should see a shrink immediately. My Vette has a 350 hp 330 tork LS1 and its docile to drive, but at full thottle it is a pure animal. You rip thru first and second gears so fast, it is difficult to stay out of the rev limiter. An MG chassis would never hold up, nor could you hook up that power to the pavement and keep the car looking like an MG. The vette has traction control to keep that vehicle going straight.
CW Strong


Now you have done it :-0 . I can't tell my shrink, he will want to do the swap before I do!

Seriously though, the LS1 is not any more potent than a lot of the 302 fords that people are already running. My interest was sparked because the engine is being used in a bunch of Miatas to the point where there is a kit available. It fits in the confined space and fits the weight criteria. I believe it can be hooked up to a T5 if the 6 speed is too big. Although it is MUCH more expensive than a 302, I imagine by the time you mod the 302 to similar power levels, it would be a wash. I would prefer the factory build of the LS1 for its reliability versus anything that is home built. The sump is in the rear; mayhaps it would clear the crossmember? The oil filter is tucked into a corner of the oilpan, so it would not be a clearance issue.

What is unkown is if it has any fitting quirks that make it hard to install.


Very likely the steering clearance is an issue. It's so close with the BOP/R that often special header bolts are necessary, there's not 1/4" to spare.

Jim Blackwood

Pete, since you are serious, screw the LS1 and go straight to a crate LS2, they are available for 6500.00 US. It is rated about 400 hp with I believe and could stand correction about 425 lbs of torque. Either way, the stock LS1 or 2 is a better engine than a 302. The weight is less and you have to remember it is stock from the factory. In another year the ZO1 version of the LS2 will be available with 500 hp from the factory. I dont know the specs on the T56 but anyone considering a conversion like that ought to go with a new 6 speed auto. It is built to handle the torque of the LS2 engine.

No matter how you cut it, you still have to hook it up to pavement.
CW Strong

Whatever your estimate build price is- triple it. There is over $15k tied up in my car right now and it isn't near running. Of course, the modifications to the car are somewhat more radical than most conversions. Most of the MG has been removed from the firewall forward.

The steering column was an issue with the LT1. The frame rails are also pretty close to the engine. We also found that radiator mounting would be difficult without moving the engine backwards.

If anybody is interested in more/better pictures of the car feel free to e-mail me.

Michael- Is that weight number for the 3800 V6 with 4L60E Autotrans 498 #? May I ask your source? Reason I ask is I am in the middle of the 3800/4L60E swap into a 79 LE roadster, and have had much difficulty finding weight numbers for the combo. FWIW, my current problem is steering clearance from the rack. It's gonna be a fiddle! Vic
vem myers


What front suspension are you using? Is it one of the aftermarket ones available or did you do a custome one?

I have seen your site before, and decided that the chev was NOT a good candidate for a swap based on the mods you had to do. Looking at the LS1, it looks to be a lot different in size than what you are using. The question of LS1 dimensions versus the earlier smallblocks was my main interest. Also, I think that the 6 speed is a bit too much; with the weight and horsepower, leave it in 5th and just stomp on the gas!


Pete- Right arm on that 6 speed....just too many shift options with torgue that will take you from stopped in 3rd gear. Vis a vis, I have a T-56 growing moss on the shelf if anyone wants it! V
vem myers

The front suspension is from Fatman Fabrications. It is a one-off part for my car based off of measurements we took on the new frame rails. It is Mustang II style with coilovers. Front shocks are an adjustable aluminum type by Carrera, springs are rated at 400lbs per inch.
The numbers I found on engine size indicate that the LT1 is slightly smaller than the LS1.
27.5 inches long(water pump to bell housing)
24.75 inches wide
24 inches tall
525 lbs with all accessories

28 Inches long (Water pump to bell housing)
26 inches wide
25 inches tall
425 lbs with accessories

Yea, the 6spd may be a bit much for the car. I based my transmission selection off of my experience in a 98 Camaro Z28 with the T-56. The 6th gear cruise RPM is appealing. It will basicaly idle at 70mph.


I think you finally answered the question. The LS1 is larger than and thus harder to install than a "old style" small block chev. I know that anything can be swapped into anything, but it looks like the GM option continues to be a "not natural" installation. The ford and the rover are safe for now.

How is the project comming along?


Project is coming along at less than a snails pace at this point. Bear Essentials who I have doing the modifications to frame and body has become excessivley slow. The owner and main mechanic Bear, (there are two guys that do all the work and one lady who does paperwork) has a few clients who race in various classes. So he works on a few full race 911's, 356's, Mustangs, Elvas etc. His other employee does body work. Without going into great detail, all of the shops attention has been turned to a '30 Ford Model A with a SBC(owner of ford bought car for his wife who developed alzheimers, wants to finish car before she dies) and the various race cars. My car has been pushed to the back of the shop and has been collecting dust since early August when I dropped by the shop and forced some work to be done to the car. I am not far from pulling the car out of that shop and moving it to a different shop. My father happened to race with Bear years ago so we know his history with street cars, drag cars, and road course cars. My MG ended up at the shop because we knew Bear could do the work properly.
Bear's personality earned him his name, he works his own pace and schedule. He keeps a single shot pistol in his toolbox and will throw wrenches when he gets mad. His desire to work is unaffected by how much money you wave in front of him. I have yet to hear of any person other than a lawyer to force the man to do something he didn't feel like doing. When he gets in the mood to work he works very quickly and produces a very good product. Thats why my car is there.


I did not realize that you were farming out all the work. I do not want to think about the expense that will entail!

As someone who works for a living, I am still looking for the secret to how some people can work in their shops when they feel like it and tell people to P--ss Off when they ask for work to be done in a timely manner. It seems to be a specialty of any shop that works on brit cars! I hope the Bear stops his hibbernation so we can see an update on your site someday.


HAHA, as do I.
My father and I could have built the car on our own. We just felt that the car would be better if the heavy fab work were done by somebody with more experience.(our fabrication experience is not up to this challenge)
We will do the final drivetrain installation, wiring, fuel and hydraulic lines, etc. It will be close to a bolt together operation when the car comes home from the shop. So yea, I am only halfway building the car.

If you are interested, I have a few pictures of the engine sitting in the unmodified engine bay. It almost fit where it was supposed to!

This thread was discussed between 22/10/2005 and 02/11/2005

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