There is a little wiggle room in the oil pump drive... But you do know the early 302/289 oil pump drives are 5/16 and the later 5.0 and 351W drives are 7/16 hex right???

 

wow thats a new one to me,i would suggest getting another pump and see what happens,perhaps that pump is screwed up.

 

Yeah I know they're different sizes, I've got a thicker FRPP shaft for a 5.0L

 

then your pump is jacked, or its installed wrong... if the drive shaft wont lay center in the boss,,, there is a problem.

 

firstly,
..the pump cannot be "just bolted on' to the block.

proper alignment is needed to position the HEX drive shaft...the pump...and the distributor shaft... all in alignment..
in so by doing, this will also reveal if the base of distributor housing is actually sitting FLAT and HARD all the way down to the block...because of many factors, the distributor could be longer, the shaft longer or the pump shorter...
also must check that the distributor gear itself is SEATING on top of the ledge inside block....but still has proper freeplay upward when base of distributor is tightened / clamped down....
hex shaft has to be able to "float" with some endplay or else it will put pressure downward to pump and pump will then fail.



while engine is out of car and on a stand,...it is alll easier to see.

 

when engione is in car, ..

the HOL E that distributor and hex drive drop into,...in block...
IS NOT exactly square to the ground...EARTH... it is tilted... so, when putting in hex drive from the "top" when engine is in the car...( and you think that the end-play clearances are correct)...
...you have to put onre front tire up on top of a 2X4 board so that corner of car is tilted according to the orhger front wheel....
...this should make the hol E in block more swquare to the ground and thus the hex shaft MAY appear to be a little more centered in the acess hol E....distributor install / drop in...may be easier..

most hex drives have a pointed end of the hex to help getting the distriutor shaft to fall into place.

 

Kato, Relating to this same subject, after you remove the oil pump and install the new shaft, should you put some oil on the oil pump bolts and torque them or do you clean all the oil off of the threads on the bolt and in the block and put red loc-tite on them and torque them???

 

Opinions may vary but I used the gasket(some don't), I cleaned the bolts and ran a thread chaser through the holes, used red loctite and torqued them. I do not want them coming out easily. I also took the new melling oil pump to my machinist and he checked it out before I ever installed it. Got burned on a melling pump before, I check every single one regardless of brand now.

Matt

 

you should do the TRIAL MOCK-UP to test the overall alignment and hex shaft length / fitment along with the underside of drive gear fit to block with end play BEFORE YOU PUT loc-tite on the pump mounting bolts with a gasket...

we actually use a pair of 3/8-16 socket head cap screws and proper AN washer,....( allen wrench) to torque ....and drill the heads for safety-lock wire.....

 

might as well just get the giant sledgehammer and pound it in.