Hi John
To fit the GC inlet you need to use cap head bolts and I found it easier to remove starter as well, then I used a 1/4" drive 6mm Allen key socket with wobble drive and just manged on get it on..... Not easy you have my sympathy there!
Have you done anything else to the engine? Are you using an electric fuel pump?
Fitting twin 45 DCOE /DHLA carbs can be worth up to 10-18BHP with no other mods, provided they are jetted correctly. Throttle response will be better, cold running better, improved part throttle response/economy, and generally you don't need to use the choke, 3 prods on the accelerator is enough to squirt some fuel in to start, remember you have 4 accelerator pump jets now instead of 1!
Make sure you have a cold air intake, sucking hot air from the radiator is not good, it will rob power and also cause detonation in hot weather, I have made an airbox out of alloy, insulated it and have a remote pod type air filter that sits behind the passenger side headlight, it also reduces the induction roar, which will be very LOUD! (a great noise but can be a little wearing in a road car).
A fuel injection type in line filter does wonders for stopping crud getting into the carbs.
The key with twin carbs is to make sure they are jetted and setup correctly. It is a myth that they need "constant tuning", I find them less hassle than the standard carb, but I am biased......
Good luck!
