um...er... merged header and turbo muffler

[beetletom]

fitted it onto my 1300 today, to see what it sounded like, is extremely quiet, and had no power whatsoever 

whats the minimum sized engine it will work on? a 1600???
the muffler itself is 2 1/2" bore

not sure what size the header is

thanks

[bugnut68]

I would say no bigger than 1-3/8 inch diameter tubing for a 1300 engine.  Check the tube diameter at the flange going to the cylinder head to see what the internal diameter is.  If it's killing your engine's bottom end power, odds are it's too big.  Most merged headers are offered in 1-1/2, 1-5/8 and 1-3/4 inch sizes, if not bigger for all-out race engines, while the standard small-flange, swedged collector (non-merged) heater box headers typically measure 1-3/8" in dimeter on the primary tubes. 

[benssp]

if your running single carb, you'll get problems with tickover without heatrisers to the inlet manifold it'll probably ice up