I put MAF's 6 into 1 header on my '68 FJ40 back in 1977. Fit was poor. Different flange thicknesses required making half moon washers to tighten it up. But, it lasted 25 years before it rusted out. (It did end up warping a bit, and took 2 gaskets to seal.)
I replaced it with SOR's 2 piece header in 2002. Much better fit, flanges the same thickness as the intake, and it may be less likely to warp because the flange is two pieces instead of one. Still needed 2 gaskets to get a good seal.
As for performance gains, the header DID make a difference. On a long uphill grade in western Maryland I drove frequently, my 3 speed couldn't pull 40 mph in 3rd gear, so I had to drop down to 2nd and do it at 35. Long haul...With the headers, I could pull the hill in 3rd at 45 mph.
I put in the fluid heatriser last winter. Hard to say how much it might have helped. It was 15 below zero a lot this winter, and long warmups were necessary to make the defroster work. I don't know if the heatriser actually helped, but it made me feel better knowing I tried.
I replaced it with SOR's 2 piece header in 2002. Much better fit, flanges the same thickness as the intake, and it may be less likely to warp because the flange is two pieces instead of one. Still needed 2 gaskets to get a good seal.
As for performance gains, the header DID make a difference. On a long uphill grade in western Maryland I drove frequently, my 3 speed couldn't pull 40 mph in 3rd gear, so I had to drop down to 2nd and do it at 35. Long haul...With the headers, I could pull the hill in 3rd at 45 mph.
I put in the fluid heatriser last winter. Hard to say how much it might have helped. It was 15 below zero a lot this winter, and long warmups were necessary to make the defroster work. I don't know if the heatriser actually helped, but it made me feel better knowing I tried.
