Cylinder Head Test Stage 1 Tune
standard Sport head modified the inlet ports Martin opened up, then also a shaving inside the exhaust port to remove the narrowing around the valve guide, next the valve throats were blended to match the rest of the modified ports.
The combustion chamber was also re shaped, the head was skimmed to bring up the compression back up. This mod is reputed to add 6 to 7 BHP depending on capacity.

Verdict
The head fitted to the engine in the Lotus Imp "painted in Lotus Cortina colours. I am pleased to say its a flyer, currently running on a Sport exhaust and 22mm Solex with K&N when tested one evening on the German Autobahn it even managed to pull 90 in top gear 6000Rpm "there must have been a tail wind".

As always this mod was a lift in performance but its never enough so 12 months later is now onto stage 2 of the development.

Cylinder Head Stage 2 Tune

The Lotus Imp gets its head, fresh from MHTools fitted with new valve seats, bigger valves and ports modified specially sized for the 875.

The head now fitted and bedded in and re-torqued down.

Verdict
What a screamer still on the 1.25 Inch Strombergs, K&N's and a sport cam and exhaust the difference is amazing more bottom end as well!

Cylinder Head Test Stage 3 Tune

Next the head gets some 360 lift valve springs as it is getting an R17 cam fitted this will boost the top end but knock out the power below 3000 rpm, hope to get the car on the rollers to see what the power is before with sport cam and after with R17-------report back when its done