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V8 into a standard RB BGT, advice

Posted: Wed Jul 05, 2017 11:54 am
by Not_Anumber
A friend has kindly donated a good SD1 engine and an LT 5 speed gearbox so it would be rude not to fit this in my BGT. Can anyone please recommend a list of parts i should start looking for to make the conversion ?

Its a 1980 standard late rubber bumper MGBGT.

Re: V8 into a standard RB BGT, advice

Posted: Mon Aug 07, 2017 7:14 pm
by Not_Anumber
The Roger Williams book seems to be aimed at 200bhp plus cars and involves the use of upgrades which strike me as less likely to be necessary if the intention is to produce something closer to the original MGBGTV8. which was frankly a cracking car just the way it was.

Though I do have access to an LT77 gearbox Im conscious this would need a custom propshaft made plus bodywork mods to the top of the tunnel to provide clearance, speedo drive etc,etc. Its not clear to me why it would be worth doing this when I could use the standard 4 speed overdrive box which is currently in the car as it was regarded as strong enough for use in the factory MGBGTV8. What are the convincing reasons against ?

Equally, many converters extol the virtues of using the later MGRV8 style manifolds, presenting this as the only way to go. I can see it may be a little better than the BGT V8 was for cooling but block hugger manifolds can be bought for less than half the price and wouldnt need any holes cut in the inner wings.

Also - bonnet clearance seems to be an issue almost whatever way people go on the inlet manifold. Accepting that a bonnet bulge is probably going to be inescapable then is there any real reason why i shouldnt reuse the SD1 manifold and carbs ?

Id be grateful for any thoughts

Re: V8 into a standard RB BGT, advice

Posted: Thu Oct 19, 2017 10:25 am
by Cyprinus
Hello, the suspension is heavier on a V8 the brakes are different also. Have a look at them on the MGBhive web site they are pretty good with their parts lists and it should give a good idea of what will have to be uprated.
Are you sure that the gear box on factory built V8 is the same one as on your 1980 MGB with overdrive? I am not 100% sure but THINK that I have read somewhere that the gearbox was different due to the higher torque on the V8. I may be wrong but I will try to find the book or magazine with it in and let you know if and when I do and what it says.

Keep us up-to date with how you are getting on with the project. I am at present doing a preservation/restoration on a 1978 MGB GT, keeping it as near to how it was produced as I can.