Part # 21814, as above. Whats the torque setting on the bolts that fasten it to the block? I cant go above 20ft/lb or it wont turn, Iron ones are 30ft/lb IIRC.
TIA

Check the mounting bolt holes,you made need to ream them a little.Sometimes if the alignment isn't perfect and the bolts bind in the pump housing it will cause it to distort.You should be able to put all the bolts in and turn them in with your fingers.

I have the same problem - I'm using the Milodon spacer plate and a Muscle Motors cast aluminum cover and a stock iron pump body.

I'm going to pull it off and try just bolting the pump together and torquing to 30 ft/lbs. If it still binds then there's something internal.

Many times you need to loosen the two small 5/16 cover bolts then put the 4, 3/8 bolts in and fasten the pump to the block,then tighten up the cover bolts,or do as I mentioned before and ream out the 4 holes for the fastner bolts.

Still having the problems even after the holes have been enlarged. Tightened it up to 30ft lb and ran it on the drill, no oil but the rotors are covered with moly grease. After a couple of minutes the drill would almost stop so I stripped it and noticed witness marks (not scores) on the bottom of the driven rotor. Looks like the rotor has been distorted when the shaft was fitted / pressed in. Checked it with a rule up to the light to confirm. Flattened it a little with fine emery paper and it's fine at 20ft/lb but I'm still not happy at 30ft/lb, I'm starting to loose confidence with this piece
I'll assemble as Stanton suggested to see if the issue is the pump or the block. Never had any issues with iron ones and we use a Milodon dual line system.

PS this is an aluminium bodied pump btw.

Tig, i just snug my bolts with Indy cover and steel pump i use a litle locktite and keep my eye on them 20lb is ok

The installation instructions for my Indy pump say in underline: "Be sure not to over tighten the pump to the block." Tighten bolts evenly with the final torque rating of 16 ft./lbs.

Tig, I've had two sets of new bad Milidon gears for there pump One set wouldn't fit in the dang pump and the other set wouldn't hold the prime over four days of sitting The last three sets seem to work fine

I've assembled the pump off the block and it's still difficult to turn at 30ft/lb
At 20lb/ft it's fine so 20ft/lb and a bit of loctite it is. Ran it up on the drill with a sump full of oil and it seems fine, up to 60psi.
Think I might turn it down a bit since usually it's just over 50 on the drill.
Thanks everyone for your responses, appreciate it.
Tig