Sorry to sound thick, but cars are not my thing! Im trying to track down a carb for my ford p100, so my mechanic can fit it. Now hes told me its a weber ford pinto with 4 bolts to secure it to the manifold. As the engine is a sierra one, and a 1.9 ive seen one on ebay, but the gut informs me its come from a 1.6 sierra, otherwise its perfect in all respects. Does the difference in engine size matter?