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MG MGB GT V8 Factory Originals Technical - 1965 MGB + Chevy 305

Our (my wife Stef and I) MGB has been slowly coming back to life for the last few years, the body is almost done, the one thing that has been bothering us is that itty-bitty 4 banger up front.

We have discussed various ways of dealing with this problem, including leaving it as is and putting up with it, dropping in a late model Japanese lump to give reliability and adequate power and various other options, including a V6.

Then our neighbour announced he was swapping out the 305 in his Camaro for a 350 and the 305 would be available for sale.

I have done a little research into this swap and those people who have done it are all very happy indeed. I was talking to another V8 owner last night who is all for the idea, we discussed various problems and solutions, such as how to deal with the rear mounted distributor. We also discussed rear axle and transmission options, we agreed a C rear end would be fine if I could find one, however, I suggested a T5 gearbox but he recommends an auto box.

We also discussed front end/crossmember issues, spring issues etc. and came up with a few ideas.

The engine has been warmed up slightly and puts out about 265BHP.

I would appreciate any thoughts, ideas, problem solving, suggestions, etc. anybody here may have on this conversion.

I have built a couple of Rover V8 Bs in the past so I'm not a newby to the V8 conversion scene.
Mike K Barnes

why not a warmed over 302? I think they're smaller physically then an sbc aren't they? If you do an auto box, prepare to chop the living crap out of your transmission tunnel. Even if you do a 302 you'll still be chopping. Hope your car hasn't gotten its paint job yet.

Do a ford 302, get yourself around 400hp, and call it a day. =)


Having actually done a 302 with a C4 auto I can say without question that no tunnel mods are necessary.But this is from actual experience.Bottom line on any V8 conversion is it is expensive,buying the lump is a fraction of the cost as anyone who has done it will tell you.Everything must be fabricated for Chevy of Ford,nothing can be purchased to bolt in as is the case with Rovers or Buick/Olds.

Dale, would you have been able to fit in an AOD if you had wanted to? I don't know the differences in size between a C4 and AOD...just curious!


P.S. Everything I have read makes it look like a SBC is really a tough job and usually requires a scoop on the hood.
G.P. Copes

Dale: You can do a c4 on the early B's with no tunnel mods? Do you still have to cut the firewall so the 302 sits back far enough in the engine bay?


Mike, anyone here can tell you that I favour V6 over the V8's anyday, but I'll go off on the V8's anyways.

V8 SBC, to my way of thinking, not a good choice...

The V8 Ford needs help with aluminium heads for weight reasons, but the SBC is worse yet. The fitment is tighter and I have seen one done locally. Alot of time was taken, but the end results were not as nice as what a smaller more well thought out unit could have been.

The WORST thing I hear from people is that they plan to do it or purchase it "because its there and cheap." Well, there and cheap usually mean headaches and heafty expense in the end to venture off the trail. I know of a wonderful straight 6 that i can pick up cheap, however, the problems with installation is horrendous. This is another reason we see cars of all kinds going on eBay with "You finish the project" somewhere in the 1st paragraph- abandoned due to knowledge that something was done wrong- usually within the 1st week of conversion.

Yes, people have installed Chevrolet V8 engines, but from everything I see and read, I do not recommend it.
A 700R4, 4L60-E or Turbo350 are all very large automatics. I am sure you can make them fit, but it will be quite a bit of work to fit a slush box and make the car even heavier. Can you imagine an MG that has poor handling due to the nose weight and still does not accelerate any better due to this AS WELL as limited tyre size in the back due to bodywork?
So now you have a car that, due to saving a buck on the motor, needs serious weight rebalancing (read- remove gearbox tunnel and reweld a few inches back, cut firewall, have a steering system with 4 knuckles in it, and so on), Huge brakes, springs for a fat MG, frame supports, large fender flares and so on just to get some of the other features back to what they should be?
So your not satisfied with the BOP/R V8 MGB? Get something better, but be careful on what you decide. The best cars are built with lots of forethought and paper scratches before the first part is purchased.
Good luck,
BMC Brian McCullough

I owned my MGB about 15+ years ago. Even back then, I always wanted to slam in a 350 Chevy. I constantly talked with my buddies and my older brother about it. Why Chevy? because that is what I grew up with. I knew pretty much every inch of the "heavy, dime a dozen" SBC. I'm not a die-hard Chevy guy, I've owned a Dodge, a Ford, along with plenty of GM's and other inports. I sold the MG to my younger brother, he had it for a few years. Then sold it again. I aquired it back last summer. I was so happy when I hauled my baby home. After 15+ years of thinking about that MG. (The MGB had many years to rust) What was the first thing I done? I Secured a "heavy, dime a dozen" SBC. Then started cutting. A lot of cutting. What have I wound up with? A project I'm building with my two hands. I learned real fast that this BBS is anti-small-block-chevy. All of my post wound up like this thread, USE A SBF. That is great advice for you Ford guys, doesn't sit well with us Chevy dudes. To sum up what I'm trying to say is: Man, build it the way it will make you happy. We might cut more with the chevy drive train, but who cares. I'm building mine, MY WAY. You should see my co-workers faces when they see the pics of my MG, huge tunnel ram, nearly as high as the windshield! Good Luck even if you use a SBF.
JWK Kerr

Yeah man, go your own route. There is one guy Alan that posts here every now and then, I think he has a 305, you may want to look him up, I think his last name is Raddatz or something like that. When I do another V8 MGB, I really am thinking of using an LS1 motor. I like the idea of an all aluminum block, plus the class of a V8. I guess I will just have to keep plugging away for now on my 215 installation and see how it turns out.

The C4 Ford auto dimensionally is no larger than a T5 so any amount of firewall work required on an earlier car for a T5 install would also be required for the auto.I looked at AOD trannies and they are much larger and require some electronics,yuck.RB cars need no work in that area or the tunnel with a SBF with either a C4 or a T5,even the shifter hole is in the right spot.I chose a Ford over a Chevy because of the weight and the physical size,Ford is narrower and shorter,albeit longer but there is room.For comparison my car weighed 2450lbs with the auto (T5 now) complete with rubber bumpers,8" rear and full fuel tank.Probably closer to 2400 now,starter change and other weight savings. Weight was split 52/48.

"I learned real fast that this BBS is anti-small-block-chevy."

I don't think we're anti-Chevy. It's just that when you do an objective analysis, the Chevy falls back in the pack of desirable choices compared to some of the other engines, such as the ubiquitous BOP/Rover, or the increasingly popular Ford 302.

Luckily, most of us don't do an objective analysis when we make our choices for a V8 swap. For example, what's the difference between a Chevy 327 and a Chevy 350? The first "muscle car" I ever owned had a 327. If I were to do a Chevy/MGB swap, it would have to be a 327, for no other reason than that's what I'm partial to. Rational analysis has nothing to do with it.

In spite of its obvious disadvantages, the Chevy engine can be, and has been, very successfully transplanted into an MGB, with great success. Nevertheless, the Ford 302 is a better choice, from a purely objective standpoint.

It's your car, it's your choice; do whatever floats your boat! The BOP/Rover works, the Ford 302 works, the Chevy 350 works, and so do a lot of other engines not often considered. I'd be willing to bet a small chunk of change that there's another V8 out there that will someday become the engine of choice, replacing the "big three" mentioned above. What will it be? Or maybe a V6?
Dan Masters

This BBS is not anti-anything, ok, maybe anti-thoughtlessness. Most of us have gone through quite a bit to come to our conclusions, and then stick with them. :-)
Study the power to weight ratio of a car. Add the balancing factor to it and you will find it even slower- like a truck with all its weight up front. Not good when you want to accelerate. Add the fact that if the rear end is going to remain MG C without any wheel well alterations and you have 195 or 205 sized tyres at the tail and you have a car that does not sound like it is fun to drive from 0-30 mph. From 30-90, it should beat me after the initial hookup, but where will the car with the better balance be? Out in front. Now, your heavy nosed car starts to catch up and then pull away.. OK, what about speeds beyond 100 mph? Is it safe on a no-wind, sunny/dry kind of day? After all, if your building a car with that much power, it should be able to beat my 150 to 300 BHP V6 and all the other V8s in EVERY way? What about brakes? Given the exact same brake upgrade to your car and mine, I am going ot make it around the track alot more then you before my brakes leave when yours are long gone from being overloaded.

OK, to get the Chevrolet down in weight to the point where it is going ot work, start to look at aluminium heads- add more compression to get the power back up to the same as cast iron heads. In other words, parts, plus machine work= $$, and lots of it. While your at it, change that intake manifold that is not going to be exactly what you want.
One great thing about the sbc is parts tend to cost a little less due to volume, but the overall project in an MG B will end up costing alot more when taking the same overall path. It will also take more time.

I guess the question is- What do you want the car to be in the long run? Reliable? A good driver? Something that handles corners at more then 15 mph? A drag racer? A custom machine that everyone will know is yours? Something for show OR go? Once you know what you want the car to be for the long haul and have a budget set for what can be done, go for Your choice!

BTW: Being I install GM V6 motors, I would prefer to see GM V8s over Ford, but these do not make the best choice for everything I have seen with my own two eyes, and read about.
Good Luck,
BMC Brian McCullough

I wouldn't say Anti-, exactly. But there are individuals here with their own opinions and we don't mind sharing them. Brian likes V6's, Dan likes Fords, I'm sort of partial to the early 215's, etc so that needs to be taken into account. I think the main reason there aren't more diehard bowtie fans here is that the SBC/MGB swap is a B***h for the most part, and the bias you see is more a case of a desire to see the conversions completed. If a 500 cubic inch Hemi can be put into a Spitfire then clearly you can swap in just about any engine if you want it bad enough, and even make it handle and brake well. But a swap goes off track very easily. If the needed parts can be bought off the shelf and it's mostly a matter of bolting things together then most folks with a little mechanical aptitude can handle that, as you know from your past Rover projects. But the real question is, are you and Stef willing to wait while the problems of engine mounts, headers, steering, cooling, ancillaries, and interferences are worked out? Because that will take time, more than any other scarce resource such as money, which it will also take of course and which is no surprise to anyone.

As far as handling is concerned, nobody has truely determined how much weight on the front end is too much. Mike Moor has shown that a Buick cast iron 300 block with aluminum heads can do quite well, thank-you, and the 302 bunch are quite pleased with their weight penalty. How much heavier is the SBC than Mike's motor? I don't know. Maybe not that much. Certainly the 300 should be heavier than the 302 with aluminum heads. But if I was starting over, and I've said this before, I'd take a close look at an aluminum 350 crate motor. Expensive at about 6 grand, yes, and a difficult swap, but what a car that could be when finished. Assuming of course it did get finished. Quite a waste of time and money otherwise.

Now, just so you know I understand where you are coming from in spite of having a 215/MGB, 24 years ago information on MGB/V8 swaps was nearly nonexistant and parts were even scarcer, yet I took on the challenge anyway, and within a few years had a running car. Note well, I said a few YEARS! And not a finished car, just one that could be driven. When was it finally finished? How about last year. Well, no that's not true either, the seats still need to be done, and now the carpet really should be replaced again. So that's just one example of what you could be in for. An extreme one I'll admit, but like I said, they tend to go a bit off track. Anyway I'll quit now. Here's what it looks like:

But also check out these links:
This links to email addresses for 5 finished and 1 unfinished 350 conversion owners. (among the many other conversions)

Best of luck,

Jim Blackwood

"Dan likes Fords"

Actually, Dan really likes Chevies best! It's just that after weighing (no pun intended) all the options, I determined that a Ford was the best choice for what I wanted. I set aside all biases, pre-set notions, and prejudices and did an engineering analysis before making my decision. I determined that the Ford gave me the best compromise of power, handling, cost, and ease of installation. Not the best of any one parameter, but the best overall combination.

Well, I must confess - I did have one preset notion; It had to be a V8. Regardless of the pros and cons of a V6 choice, my mind was set in stone on a V8. Personal bias, pure and simple.

Depending on priorites, someone else may do an an un-biased engineering analysis and come up with a different choice.

You have two choices - go with what works best or go with what makes you happiest. Or, the best of both worlds, a little bit of each.
Dan Masters

Okay guys, I appologize for my Anti-chevy remark. Someday I might tackle another V8 conversion, maye I'll do a SBF or a 215 conversion. Then I will be able to testify they really are easier.
JWK Kerr

JWK, just a little fuel to the old fire, if you had gone the "easier" route of the 302, 215 or v6 just think you would be driving that car now with your own 2 hands instead of cutting and cutting with those hands still, just a thought. but as usual even heads prevail here, i agree with others, you need to build what you want within the budget and comfort level you have, get it done so you can get out and drive it with the rest of us, jim
jim m

Right Jim, Thinking about it, I never seem to take the easy way. (not that any conversion is "easy") If I really built (ing) it the I wanted, I would have a Pontiac engine in it....

My conversion is a budget deal. My wife isn't pleased with any "great deals" I find for it. So far I have the motor/tranny bolted in. Ram horn exhaust manifolds cut and rewelded to work with my set up.

I a buddy selling me a nice S10 rearend. My tally is boardering on the $600-700 dollar range right now. I imagine I'll have less than 2000.00 in it when I start driving it. We'll see.
JWK Kerr

Thanks for all the input, appreciated. Nothing I have read so far has put me off this idea yet. A friend and I have been doing some serious research and calculations and both figure the conversion isn't quite as difficult as some people believe. Engine weight has been mentioned several times, we calculate that the engine, in MG suitable form, will weigh about 160lbs more than the standard lump, it may be possible to get that down to about 120lbs with careful parts selection. We have also calculated that if (HUGE "if") I can get the front pulley level with the wheel axles the weight balance of the car will be 50/50.

Thanks again for the replies.

Mike K Barnes

I do not think you are going to like the 305 sbc. They are not like the 350 which are cheaper to mod and could cost more money to get small amounts of power.
Billy Brothers

I disagree with Billy. I did a 305 conversion to a small pickup and it worked quite well, despite it's stock 205hp. If yours is already has 265hp, then it's going to have almost 200hp more at the rear wheels than a stock B. What's not to like?

For those who think "more work" in an engine conversion is bad, just remember that some of us do these conversions for the garage therapy as much as the end product!
Jeff Schlemmer

"For those who think "more work" in an engine conversion is bad, just remember that some of us do these conversions for the garage therapy as much as the end product!"

Dan Masters

dan, its AMEN & pass the cutting torch, isn't it? now i thought i did my conversions so i can have fun driving them? Safety Faster
jim m

So Jeff it is not more expensive to build a 305 chevy? I question your experence in this area. By the way 200 hp is not an excesive amount and 265 where did you het those numbers from?
The G

Try a 2.8
S. M. Morris

I'm a sbc guy through and through, but got a Chevy 60 degree V6 for my conversion (slated for this coming fall).
Three good reasons:
1) There's a kit for the V6
2) the sbc (from what I've read) will destroy the MG's handling characteristics.
3) The stock rear won't explode.

And if you are going to use a sbc, why a 305? A 302, 307, or 327 would rev a lot quicker.

This thread was discussed between 14/03/2004 and 29/03/2004

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