I built mine for rallying to go in the under 1300cc class. I dismissed the standard 1256 Vauxhall lump from consideration and a friend persuaded me go the Alfa route as he was breaking Alfas in those days.doctle wrote: ↑15 Jun 2020, 19:21These young chaps don't know what a Chevette was, they maybe think we are Americans! How did your swap work out? I had Weber twin 40 side draughts and the driveshaft was wobbly. Straight line fast cornered like a 2cv with a wardrobe on the roof
The cylinder head didn't require much attention as it was already well shaped and the valves didn't have any space around them to go larger so that just left the cams to be changed. I don't remember what grind was on them. I decided to put twin 45 DCOE Webers on but had some special choke tubes turned reduce the size of the venturis. I made up a 4-into-1 exhaust manifold using welded together pieces of tubing and fed this into an exhaust system that I made up along the lines of the DTV Chevettes. I was fortunate that I had contacts in Peco who were based nearby! For the massive rear box I used something that came from a Rolls Royce model. I must have had an intermediate box to satisfy the regs but I don't remember what it was.
I only got to run it on a rolling road once. A chap (I forget his name) who used to be at Minisport of Padiham and then subsequently based in Rochdale, gave it a preliminary tune-up and got about 95 - 98bhp at the rear wheels. But he was puzzled as he expected it be more than that. It was also suspiciously quiet the faster it went. We eventually realised that the big box wasn't a straight-through, as I had been told, but a baffle type. And as the revs went up and the pressure increased the baffles became compressed limiting throughput. Something to be looked at later!