I am mocking up and measureing a 400 block 512 C.I. stroker motor, the machine shop accidently included a set of Clevite main bearings, MS867P in the parts returned to me. I normally use the Seal Power M4094 main bearings on my low deck builds but I attempted to use the Clevites, they are not chamfered on the front and back edges and ended up locking the crankshaft up once the mains where torqued down with the crank laid in the bearings They had less bearing clearances and more variences in the clearances as well as the bearing shell width varied a bunch more (.004 compared to .0010) on the Clevites bearings I checked than the Seal Powers do The Seal Powers have the front and back edges chamfer on the bearings needed to work properly with a conventional radius corner stroker crank also The Clevites may work fine on a stock crankshaft that have the standard inverted raduis(probally not the correct name for the Mopar finish on the rod and main bearing journals on the edges of the crank journals )The Seal Powers work well on both, both sets are full narrow groove Tri metal main bearings sets but they are not equal to each other IHTH some one else avoid the pain and grief I had with the Clevites, nothing like wasting 5 or 6 hours trouble shooting a problems like this one

i use to use Sealed Power but now i use nothing but Clevites. Even with the huge radius on an early Source crank, i found the Clevites were a good fit. Clevites are definately a tighter fit than Sealed Power & in my experiance, the Sealed Power bearings would wear out faster creating lower pressure when hot. every refreshen of my engine with Sealed Power bearings would see the top coating almost totally wiped off, but with Clevites i saw much less wear, plus the oil pressure would stay higher when hot, right up to the end of our season. the only way i'd use Sealed Power again is if the Clevite company shut down & all stocks were exhausted.

Hughes Engines sells the Clevite bearings that have been chamfered for aftermarket cranks.

The stroker kit I just bought came with King bearings and they appear to fit okay with a chamfered crank so that is another option.

As far as I know, all low deck main bearings are full groove. I looked around for a set of 3/4 groove mains for a 383/400 and didn't find anything. Seems like someone should have made them by now given how popular the low decks are but I guess nobody has stepped up to the plate.

I ended up using a set of King XP rod bearings to get the clearances I wanted, both Clevite and the Seal power BB Chevy race bearings where to little, less than .0021 clearances, the King XP bearings where all .0025 +. That is using a decent dial bore gauge set with a newly rebuilt and calibrated Starrett 2.00 to 3.00 outside mike. Those XP bearings sure look bad on the outside bearing surface appearence I hope they perform better than they look

I should have posted the part numbers originally, they are the Clevite MS877P and the Seal Powers are thier 4094M. Both look like each other, narrow full groove and both are suppose to be Tri Metal materials. Sorry for not doing that to start with

I just test fit some King main bearings on my 470 and the bearings are narrowed so they fit with a chamfered crank. Guess it must be easier to make a narrow bearing than a wide one that is chamfered.

I talked to King about 400 mains for my 528 build. As soon as I told them I planned on hitting it with nitrous, they said they didn't have a bearing to recommend and told me to use Clevite. I went with the chamfered ones from 440Source. I'm hoping to start mocking it up soon. Not a ton of choices for low deck mains so I hope the clearances are decent.

The Clevite MS877H or maybe with another suffix letter may work for you