Folks, I now have available spike needle valve assemblies and venturis like on the Rustler 40, for the 35/40/46 FP and LA series. Venturi dia. is a nominal 0.1875". Effective area can be varied a little by screwing the spike in and out a little. Price is £13 per matched pair, (= $22) at this week's exchange rate. Also the old (small) type Merco mufflers machined for 35/40/46 FP/LA, at £12.50, ($21.50).
Ian R.