So I have picked up a tidy but not perfect 74 Leyland with a stock 1098.
It’s not wanting to rev very freely and I want a bit more pep out of it. I don’t really want to fully rebuild it but I realise $$ need to be spent. This is what I am asking you guys n gals for a direction to start with. Twin SU set up? It has electronic ignition but the rest is bone stock. Is there a after market head I can throw on?
Cheers in advance. I’m in Melbourne by the way if you know someone I can go chat to to get it done?

If it's that stock it probably has a 1 1/4" carb on a one piece cast iron manifold which combines intake and exhaust. Very restrictive.

Twin carbs don't make any more power. You're better off with a big single 1 3/4" carb, a HS6 or HIF44, easier to set up and way cheaper. I even have a HIF44 on my Cooper S.

Coupled with a bigger carb is a nice set of extractors and a 1 3/4" exhaust.

You'll be surprised how much better it goes when you do that and have it tuned properly

Edit: there is a listing of businesses here viewtopic.php?f=41&t=83593

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did I tell you that I won a trophy?

A 1.5 inch SU will be a good upgrade and defo change out the combined inlet and exhaust manifold as you also get a lot of heat transfer from the exhaust side to the inlet side. The mini sport heated manifold can be found fairly easily and will be a lot less restrictive too

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Rob Forsyth
Miniot!!

My suggestion in cost and effort order:
Full service and tune, check the compression, timing and valve tolerances etc
Minimum of 1.5” single SU with separate manifolds and full exhaust system
Performance modified head with bigger valves and porting. These are normally done on exchange or on your own head - small bore stuff normally isn’t stocked on the shelf like 1275 heads
Performance cam (normally means taking the engine out)

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"It’s not wanting to rev very freely" = Step Number 1...find the cause...

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"Show me the Mini!"

A Stage1 kit is a good upgrade for not too many dollars.

I am absolutely with 9YaTaH. A good mini K is not that far behind a 1275 in many situations. Find out if it is slow or normal ! get someone to drive it who really knows. If it is slow, work out why before you buy some of the so called hot up bits.... What dissy ? whats timing set at ? what needle is fitted ? What diff ratio ? every step taller in ratio knocks around 10% off your available power ? what fuel have you put in it ? what plugs ? do a compression test first .... dont thow the baby out with the bath water!!! If you do not have proper compression and an accurate and competent ignition system it will never perform decently with ULP no matter how much bolt on stuff you throw at it. cheers Lindsay Siebler

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1967 EX works rally mini restoration virtually complete OBL45F
1965 Mk1 Cooper S
1970 Colt 1100F SS
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

Cheers guys. I have sent it down to Len Read to have a look at it and give me a idea on where it’s at as a base point.