Harold's F'ing me over - big time.

Oaklacar & 440WIP.... this guy builds custom headers to YOUR car ON your car. That is his business, he does custom exhaust. I asked him to copy the set he makes for me and put them up for sale...his reply was kind of interesting!? he asked me WHY? he said why should he make headers for customers he has never seen...I had no answer. He further explained that he has no intention of trying to compete with TTI ( and others) who already do it...why bother? Makes sense to me. He builds custom exhaust to each of his customers cars. TTI's and Hooker & Hedman are already doing that.... his point being the only way to ensure a positive correct fit that does not require modifaction of any kind , no dimples etc etc...is to custom make the headers for the specific car in question. He has a point.

AbodyJoe
engineers and computers can be wrong NO dispute there. a quick check of your credit score and IRS records along with several attempts to keep airliners airborn via computer prove that beyond a doubt. HOWEVER....the manifolds used were the 340 TA types and they have been repeatedly tested by several competent technical sources to be around 5% less efficient than TTI or Hooker headers.....which are presumably a marked percentage more efficient than spitfires....leaving a range less than 5% for the spitfires. benefit of doubt 2.5% ....the tri Y design causes somesort of undesired turbulence which reduces the pull & flow synergy produced by full sized headers and is said to reduce the overall efficiency to equal or below the stock TA manifolds ( not regular stock 340 manifolds :) My only question to you ( not sarcastic ) is you claim to be able to "feel" a potential 2.5% improvement? OR you were not using the TA manifolds? if you were not using them then you likely felt an improvement in excess of 2.5% which maybe makes sense, but if you are telling me that you felt a possible 2.5% improvement, then you are one sensitive guy!! ( friendly sarcastic) And I would bet you would also notice a pea under your mattress.
IF I was forced to pick between the top technical exhaust designer at GM using his multi million dollar computers and software and what You feel .... no offense but my money rides with Him. THAT coupled with Harolds poor business practices , poor communication COD requirement and a wait time that exceeds the "second coming" leads me away from even considering Spitfires for any reason.
just my 2 cents