dual carbs

[pflaming]

Carbs is on my to-do list for my 51/52 inline six. Question: What is / are the reason(s) for adding dual carbs? Conversely, why keed a singe carburator and which is recommended?

PF

[greg g]

Two of the easiest changes for flatheads is more compression and better breathing. For the investment, these two changes yeild the most bang for the buck. So a dual intake addresses part of the breathing equation, by allowing more air and fuel into the engine, and balances the intake charge better by placing the carbs closer to the cylinders they are feeding. Dual exhaust also adds to the breating equation. Milling the head and decking the block are also easy and fairly inexpensive, and it follows that if you have a better fuel mix in the cylinder and squeeze it tighter before lighting it off you are gonna get a bigger bang. The question of how much always comes up when discussing milling and decking. George Ashe says a combination of up to .070 will still support regular gas with nor worrys, and .090 is possible but needs premium gas. I have dual carbs, .050 off, .040 off the head, .010 of the block, and single exhaust. My machinest did some calculations and estimated my compression ratio is an the 8 to 1 area (perhaps marginally higher) my exhaust is a custom bent deal that is 2 inch id all the way back with a thrush turbo flow low restriction muffler. This set up runs very well, gets decent fuel milage and responds well to gas pedal input. I feel it is on par with my regular cars in the 40 to 70 mph range. Keeps up with traffic with no problem. Seat of the pants says it is much more responsive than the former engine. So if you want to spend some money over and above a regular rebuild, these changes will give you an apprecialble increase in performance on your flathead.

[Reg Evans]

Well said Greg !!!