start with the carb by replacing it with a weber 2e3 (cheapest and easiest) then go for a fast road cam and change your ingnition to electronic if it isnt already. then gasflow and port your head maybe with bigger valves. and then go get your self a 4-1 manifold straight through to a free flow back box. you might even be able to fit a 1.6 head on your lump and then get larger valves
I was in this position many years ago. Problem I found was that the more powerful cars were so cheap (GTE's for £1k) that for the cost of any serious mods I could of just bought a GTE. The problem is insurance.
A 1.6 engine is about as cheap to insure as the 1.3 so chuck one of those at it. Its alot cheaper than cams and manifold and things. Thats gives you 90bhp and with a bigger carb you can hit 100bhp. Then leave it until you can insure something faster otherwise you will spend thousands on something that is worth £500 and in the end will still get trounced by a 2 litre.
I would suggest tuning your chassis instead, the insurers cant have you for that. I'm talking lowering kit, strut brace, poly bushes, v6 brakes, rear disc conversion. I also spent hundreds tuning my 1.6 to 112bhp, in the end i sold it for 250 quid cause my mate beat me in his 5 year old corsa gsi. Then i went out and bought my gte16v and the rest, along with most people i race, is history.
insurers can have you for anything non-standard, bear in mind you're not covered for big payouts (but are are covered legally probably) unless you tell em and they could charge you ££££ depending on how evil they are
Quote: gas flow" the inlet manifold where it meets the carb.
Is this a good idea? My mate reckons the inlet manifold should stay as it is, otherwise the mixture doesn't mix properly. The turbulence caused by the roughness helps the mixing of fuel and air? He is obviously all for polishing the head though.
Correct, you need to promote turbulence in the inlet manifold for good mixing. That's why polishing is out. But there can be too much turbulence, I was thinking mainly if you fit a Weber carb with the adaptor plate, in that case some work with a grinder would improve matters. As would matching the manifold to the inlet ports on the head.