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MG MGA - Which carbs for an MGB head on 1500 A

I have just acquired a recently restored 1500 engine with an MGB head. ( about 5000 k's)

Can I reuse my 1500 manifold and carbies ?

If not, what mods are needed to get the best out of the set up?

Apparently the engine is set up with "hepolite " pistons and an "iske" fast road camshaft- and to make it even better, I'm not sure what any of that really means.

The 1800 head was added to "improve breathing"- does this really achieve this?

Also, can I reuse the old "correct" 1500 head without any problems?

As Bubbles in " AB FAB " always said...
"questions, questions, always questions!"

correct email

namatjira "AT" mac.com

M THOMPSON

The 1500 carbs (and manifold, including exhaust) will work just fine, they are 1-1/2" just like the later MGB carbs. Some 1800 heads had larger intake and exhaust valves. You'll have to look at the serial number under the valve cover and use that to determine what year it came off of. Barney Gaylord's MGA Guru site has all the head information you'll need. As far as putting a 1500 head back on, I say don't bother as the larger valves actually do improve the engine's breathing espeically with a higher lift camshaft. If you really want that 1500 head back on there, it will work.
Mark J Michalak

A lot depends on what has been done to the engine and cylinder head. In its standard form the 1800 head has a much larger chamber volume than the "standard" 1500 head. If the 1800 head is put on a 1500 engine with no other changes you will have a very low compression ratio.

The assumption has to be that either the Hepolite pistons you have fitted are domed to give high compression or a lot has been machined from the 1800 head to reduce the chamber volumes. If, as is most likely, you have domed pistons then the 1500 head cannot go back without changing the pistons or you will have a very high compression ratio.

The standard SU carbs will be OK but might need the needles changing but what to I have no idea.

Malcolm
Malcolm Asquith

Your best bet is to find a tuning specialist and get the carbs set up on a rolling road. This identifies whether you are running lean or rich throughout the rev range and an appropriate needle can be identified.

Malcolm
Malcolm Eades

This thread was discussed between 14/04/2010 and 17/04/2010

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