Hey

I have a 1977 Pontiac Firebird with a 403 and I recently sent the crankshaft out to get machined and once I got it back the mains were .010 and rods were .020. When I ordered the undersize bearings for both I thought I was done, the Mains fit perfectly but the rods didn't even come close like almost a 1/4" on both sides of the cap. I verified that the rod bearings that I ordered were right and, was on the phone with summit and they told me it was right. does anyone have any suggestions for finding the right bearings???
What's been done to the engine thus far
- stripped down to the bare block
- w-31 cam from summit
- 4A heads ( I know they are massive)
- mild porting of the intake side of the heads
- stone honed the bores for better cross hatching
- On order is an aluminum intake Holley street dominator from Facebook market place
- Holley 650 cfm carb and the jet kit is also on order
- Comp Cams Timing set ( non double roller)
- New lifters and Push rods
- Looking to get the lower end engine girdle from Mondello

Mock up

Machined Crankshaft

Main bearings

w-31 Camshaft

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What's the part number of the Rod Bearings you have?

Small block rods have a 2.25" connecting rod bore
Big block rods have a 2.625" connecting rod bore

 

the part number for the rod bearings
is : 87050CH20 speed pro competition

 

Those are Pontiac bearings.

 

Yeah I did see that and under the applications it shows it will work with a 403 oldsmobile hind sight 20/20 should have asked before :/

What bearings are the go to for small blocks