I think the TTI headers are a rip off. I used a set of TPIS headers on my 92 Vette they were the most expensive headers I ever bought at $750 but they went in in about 20 minutes so I thought I would never buy a cheap set of headers again because the TPIS headers were perfect. Well TTI taught me otherwise. They just give you enough info to get you to buy them and yes you to death the whole way. I told them everything I had on my motor and they said they would fit fine. Then during install I find out they don't work with head studs so I had to take them out and replace a couple head studs with bolts. They said they would work with an OEM starter yea right I had 3 mini starters here none of them would fit so I had to buy another mini starter for I think $200 and still had to bend one of the tubes so it wasn't sitting on the starter. All in all it took 2 day and about 10 phone calls to Sam at TTI to put the headers in. the last call I had with sam ended with if I have one more problem with these headers I am going to throw the thru your window what a joke. Then to top it all off I ordered the nickel plated headers because I hate the look of rusty headers I wiped the headers down with alchohol before fire up like they said and the damn things turned brown at first glance they look rusted I hope I can find something to clean them up with