My machine shop called me yesterday and said my block would need an align bore due to it spinning the 2nd and third journal main bearings. They were way off, I went up there and had a look for myself. These are my measurements from the inside diameter of the mains: 2.69 .44, 2.7 .48, 2.7 .68, 2.75 .90, 2.7 .45. My question is, would it hurt anything to have this block line bored? The crank has to be turned .30 on the mains and .10 on the rods. He said it won't affect the motor at all but I've always been kinda iffy about turning a crank that much and having the main caps all jacked up like that. This will just be a heads and cam N/A 10:1 compression street motor. Thanks

 

I really dont under stand your measuring as a 350 ID bore of the mains is 2.6406 to 2.6415. Any block we line bore we finish with a line hone which the finish is a lot better and better heat tansfer or a line bored finish.

And a .030 under crank is fine as long as there are no heat checks from the bearings spinning.

 

I thought those measurements would confuse someone, sorry about that. Sounds like I'll be good to go then so I'll call the shop back and tell him to go ahead and do the work. I've never seen one spin the bearings out like this one did, it sure made a mess. Thanks!

 

Is it a 2 bolt main?? now would be a good time to convert it to a 4 bolt main if so, and if you plan on using ARP studs let the shop now and they need the studs to have the caps torqued with them. just a few heads up that came to mind when machineing block mains.

 

Mine is a 4 bolt main, I allready have the ARP main and rod bolts so I should be good to go. I went last night to the Hot Rod Barn and picked up New Brass Freeze plugs and Clevite 77 Cam bearings which I have to drop off today.

 

If your using stock cam and springs and you bought the 290 cam bearings thats fine but if you are using more lift and better springs you may want to go to a ACL 3349 or CHP-8 Durabond performance cam bearing made for hinh spring pressures and Clevite offers a 1349 but in the performance engine industy there have been some problems out there using that part number.