I am swapping a Ford NP435 behind my 4.0 using a T-150 bell housing. Just to be on the safe side I check the runout of the face of the bell housing and the bore. The face is very good 0.002" TIR, the bore is not so good 0.012" TIR, it needs to go straight up.
The more I look on line the more different versions of what is acceptable I find. Some say the bore needs to be with in 0.010" some say 0.005" and others 0.0025". Most of the time they do not specify if the numbers are TIR or the offset of the bore. The only thing I have noticed is that the closer the source is to someone who sells off set pins the tighter the tolerance they list. It does not help that most of the sites I find that even talk about this are high RPM car racing sites, so I do not know how much of this applies to low RPM jeeps let alone 40 year old 4 speed truck transmissions.
All the offset pins I have found are solid which will not work for me as bolts go through the pins in this setup. My gut instinct is to say the hell with it close enough, especially since I have never checked this in other bell housings and they have worked fine, but I hate to have to redo things down the road.
I know there are some on here that are into high performance engines in general and some into AMC engines in particular. Could anyone comment on how close they consider close enough and how they adjust runout on AMC engines given how the dowel pins are hollow? Also am I just being silly even worrying about this?
The more I look on line the more different versions of what is acceptable I find. Some say the bore needs to be with in 0.010" some say 0.005" and others 0.0025". Most of the time they do not specify if the numbers are TIR or the offset of the bore. The only thing I have noticed is that the closer the source is to someone who sells off set pins the tighter the tolerance they list. It does not help that most of the sites I find that even talk about this are high RPM car racing sites, so I do not know how much of this applies to low RPM jeeps let alone 40 year old 4 speed truck transmissions.
All the offset pins I have found are solid which will not work for me as bolts go through the pins in this setup. My gut instinct is to say the hell with it close enough, especially since I have never checked this in other bell housings and they have worked fine, but I hate to have to redo things down the road.
I know there are some on here that are into high performance engines in general and some into AMC engines in particular. Could anyone comment on how close they consider close enough and how they adjust runout on AMC engines given how the dowel pins are hollow? Also am I just being silly even worrying about this?