The mopar 90 degree adapter clears the TTI headers on my 65 Dart/360. However, the 3/4 inch hollow bolt (with 1 3/16" hex head) must at least have the head thinned down to approximately 1/8" (per TTI). Header clearance is still very tight, and there is no wrench room to tighten the adapter in the event of a leak.
Examples of this adapter that I have seen have been generally poorly machined and some are poorly cast as well. Of particular concern is the mating surfaces of the bolt-to-housing area. However, you can't argue with success...they have done their job on many engines.
After my adapter leaked (forcing me to remove the passenger headers for repairs), I remachined the adapter. I removed approximately 1/16" from BOTH block side sealing surfaces, and approximately 5/16" from the bolt shoulder sealing surface. Total clearance gained about 3/8". I removed rough casting material from around the bolt head to provide clearance for a thinned box wrench. I cleaned up flash around internal oil passages. I unshrouded the two lower oil holes in the bolt (just above bolt threads) to allow for more oil flow. I sleeved the sloppy bolt head end of the adapter and finally installed upper and lower viton O-rings on the bolt itself. I used a teflon washer under the bolt head. (However, I recommend a dead soft copper washer).
Remachining this adapter is a little tricky, and requires proper setup and some patience to do. The rationale for doing this is that it eliminates cumbersome and potentially leaky plumbing, along with the hassle of finding repair parts when something fails. Mopar came up with a super simple way of relocating the oil filter, but you can improve upon it and make it work for you.
KenAbody
