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MG MGB GT V8 Factory Originals Technical - 72b to V8 conversion questions..

Have a 72b that has recently suffered front end damage. At this point I want to do the V8 swap I had planned several years ago. Could someone please comment on a few questions I have starting out this project?

1) Engine??? I have a complete Oldmobile 215 4bbl and also a Buick 215, along with a dual pattern 215 bellhousing, flywheel, and 400cfm carb from the Olds. I also have a few other misc parts, including 30 over pistons for the Buick. Which motor is recommended to rebuild if either of them? I have read about the Ford 302 conversions, and the advantages of rebuilding and parts costs. Even though I have rebuildable 215's on hand....is it worth it or is it easier to convert to the 302 in the earlier B's? I do want to give this B plenty of power/excitement going to all this trouble.

2) Transmission??? I have alreaady aquired an unknown condition BW T-50 5 speed with GM bolt pattern. Looks like it would fit better then a Taller/Bigger T5. However, I have access to a T5 out of an 84 Camaro with a 2.8L in it for a bit of cash, And/Or a T5 from a Chevy S10 with the short tailpiece including the shifter. Would it be better to opt for one of the T5's or use the T50 to begin with? There again.....perhaps finding a mustang with ford 302 and 5 speed all together would be the easiest convert, using all readily availabe replacment and rebuildable parts, instead of a mixture of custom made/hard-to-find componentry? Help???

3) Steering??? I have yet to find an easily availble newer MG for parts nearby. Can someone tell me the sterring changes and componentry I will need to switch on my 72? Would I be better off finding a comlete car because of the amount of componentry switching involved?

I am not a body man by no means, but have some friends that can help. I would like to know if anybody has some complete conversion kits to make this task a bit more streamlined, and lead me in the proper directions. Thanks in advance to everybody who has helped with these projects!!
Jereme Patterson

The Buick has better ports in the heads, the Olds has more head bolts but has conical valve springs. Olds 4bbl heads have a smaller combustion chamber, but piston selection ls limited, although Rover pistons might do well. In any case, try not to use the stock 8:1 Buick pistons in either engine if you can find something better, although shaving the heads about .040 is an option.

The T-50 comes in two varieties (actually 3) wide ratio and close ratio and a non-overdrive which is more scarce. The close ratio is the one to use. I seem to remember it having a groove around the input shaft splines, at any rate the wide ratio one does not. The wide ratio transmission was used behind 4 cylinder engines, and the close ratio was used behind V-6's and maybe some small V-8's There are some good articles on these transmissions in the MG V-8 Newsletter back issues, (specifically, Vol. VI Issue 2) giving gear ratios and other specifics and comparing them to the T-5, and other issues right about then give info on other transmissions, hydraulic throwout bearings, etc. It is plenty strong enough for a 215 in the lightweight MG. Depending on where you set the engine, you may be able to get the shifter through the stock hole with a minimum of bending.

The 215 provides more than adequate power in the MGB, and is a good place to start. Then if you want more power later on there are numerous performance options, including the 4.6 liter Rover engine, fuel injection, etc. I have run an Olds with a turbo and am finishing up one with a roots type blower. You can also run the '63 Buick 300 which has a cast iron block and aluminum heads, with a weight penalty of only about 80 lbs. The engine is a fairly easy fit. In my '71 I had to trim a couple of small corners in the firewall. I recommend the hydraulic throwout bearing to ease the clutch linkage clearance problems. It is possible to set the engine as low and as far forwards as it will go without the pan hitting the crossmember or steering rack, at which point the rearmost exhaust bolt may rub on the steering shaft. Creative solutions to this problem include the use of small headed bolts such as button head capscrews, grafting in a late model steering column, and the one I like best since I came up with it, using the later small universal joint and lengthening the pinion shaft to match. Stock Olds/Buick engine mounts can be used if mounting tubes are welded to the crossmember, and with the engine in this location the swaybar clears the crank damper and the oil filter fits neatly between the swaybar and the steering rack. The main disadvantage is that the radiator has to be moved forwards. (the '71 grille does not work) Also a hood scoop will most probably be needed. The more common conversion sets the engine farther back and lower, relocating the steering rack, and using a remote oil filter. I think all the fabricated parts for this swap are available, but there may be an issue with crossmember clearance in the CB cars.

There is very definitely an issue with crossmember clearance with the 302. While a great engine with unlimited options, it is more of a custom swap. Then again, I know of at least one with a SB Chevy. The great advantage of the 215 is that it doesn't affect vehicle weight or balance however.

The exhaust is the next great challenge, and the easiest solution is probably the RV-8 headers. Other options exist as well, such as custom made headers if you can weld. I use egual length fenderwell headers on mine.

As far as the economies of rebuilding the 215 are concerned, it's pretty much the same as any other domestic V-8. OTOH, complete Rover engines are becoming available at fairly reasonable prices.

HTH
Jim Blackwood

Jerome, check out my site at http://www.mgcars.org.uk/v8_conversions/ the site is a pretty good place to start if you are thinking about a V8 conversion. It will show you some of the options open to you plus the article on there by Roger Parker is a very good source of information.

I know of someone who does kits for a V6 conversion and I think he was also developing other kits. I don't have his info right now but if you want to e-mail me I'll dig it out.

Oh yeah, no connection with anyone that sells stuff for conversions - I just do that site for fun!

Cheers

MikeB
MikeB

Jeremy,
I can agree with Jim. The 302 is a more custom install. Power can theoretically be unlimited. It depends also on what you want from the car. If you want everything under a stock hood, the 302 is a big challenge, I have been building mine for over a year and am just now finally getting close. Also with power, you need traction, so there is a possibility the extra power over a 215 is not useable..

I have to re-do my mounts and finish modifying my carb. (another carb would not require modification) Then I have to custom build my headers and everything else. Things that are easy for a 215 conversion are tough for the 302, while finding parts for the 302 is easier and often cheaper. trade-offs.

Go to my site, you can see what I have done so far. IF you go 302, please do yourself a favor and buy a complete unit like tou mentioned, piecing mine together has ben half of my frustration.
Larry Embrey

This thread was discussed between 24/08/2001 and 29/08/2001

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