Posted by George (in Houston) on Tuesday, July 08, 2003 at 8:03AM :
Before heading off to Colorado for a few days, thought I'd update those interested in my WDX conversion to a 251 with NP420 trans. So far, this has been surprisingly easy. Engine went in without a hitch. Rear mounts are the same as the 230. Used the stock 251 front motor mount right to the front cross member. From what I can tell by the parts books, that's the way they were done in later years. Anyone knowing better, please let me know! I can't see using a 230 motor mount despite being told otherwise by someone (just doesn't fit). I went with the 230 style timing chain cover and crank pulley (timing marks line up if both cover and pulley are from a 230), and 230 water pump. That reduces the overall engine length by about 1-1/2" which I'll need later for the radiator. More to say on that later.
Transmission linkage needs the bracket item 21-101-4 pn#1269515 from the later years or fabricate your own from 1/4" plate. If you have a parking brake cable instead of the rod actuated type, you'll need to re-use your old transmission rear bearing retainer which has the dog leg to hold the cable sheath. On mine, I had to have a machine shop remove the aligning lip and create a mirror image of that lip (recess) as the 420 has the lip on the trans casting instead of the retainer. Alternatively (wish I knew this before hand) you could keep the 420 bearing retainer and just convert to the rod type actuator 4-20-2 pn#1271295. You'll also need the longer parking break sector gear 4-12-1 pn#1269515. If you fab your own bracket, you can just drill one more hole and use the original sector. All of this is easier then it sounds. Intermediate drive shaft just barely fit with no modification.
Carb linkage was no problem with the original carb.
Reused my alternator brackets from my 230.
Haven't figured out what I'm going to do about my temp sender. The old sender is 3/8NPT and the 251 head has a smaller hole. May have to drill it out and re-tap it to 3/8NPT to keep my original sender/gauge.
Oil sender was the same.
Hopefully in a couple of weeks I can get to the radiator changes.
If anyone has any questions, feel free to e-mail me!
George
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