Pontiac 455 and Buick 455 main bearings in Cad500

Big Cadoo!

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Here are Pontiac 455 and Buick 455 main bearings modified for use in Cad500. The Cad500 thrust bearing must be used as the Pontiac and Buick thrust bearings arent the proper width. The Pontiac bearing is 3/4 groove. The Buick is 1/2 groove. The Buicks will be installed in Cad500 to test. My crankshaft is .030 under. The Pontiacs are .010. The Buicks are the top set.
 

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Big Cadoo!

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Those are main bearings. I obtained them from a parts store with decades of dust on the packages. Im experimenting with oil pressure in the Cad500. These are performance type bearings without a groove in the lower shell. Its an experiment that I will share the outcome of with other Cadders like my other postings on this site.
 

5one9

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I think you'll have a hard if not impossible time improving the current Cadillac main bearing design. They were half grooved in the old days. I don't even know if you can buy those now. When I was neck deep in 455 Buicks, I had TA Performance 'full groove' main bearings which Mike Tomaszewski marketed as an improvement over the stock stuff. I never had issues with mine running a HV oil pump kit and 6.85 seconds in the 1/8 mile in a 3680 pound car including me. Out on the road for thousands of miles it made tons of 3rd gear 6000rpm pulls. I believe 'full groove' mains are the only way to go.

Keep us updated.......................although it may take years.:)
 

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I hadnt heard of Cad500 with 1/2 groove main bearings. Ive disessembled a 68 472 ,71 500, 74 472, 76 500 and never seen any 1/2groove bearings. The main journals may be too large for 1/2groove bearings as the oil film gets hydrodynamicaly formed by rotation. There may not be enough oil to cover all that area. There may not be enough oil flowing for rod bearing oiling without the full groove. I will keep posting results.
 

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The engine that I'm testing main bearings in is -.010. So the Pontiac 455 bearings get tested first. Also the Pontiac 455 tangs align with Cad500 tang locators in engine block. Buick 455 bearing tangs are opposite and need precise fitting...
 

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I decided to remove the tangs on these main bearing sets. Their only there for production line assemblers coming to work with a hangover.
 

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I hadnt heard of Cad500 with 1/2 groove main bearings. Ive disessembled a 68 472 ,71 500, 74 472, 76 500 and never seen any 1/2groove bearings. The main journals may be too large for 1/2groove bearings as the oil film gets hydrodynamicaly formed by rotation. There may not be enough oil to cover all that area. There may not be enough oil flowing for rod bearing oiling without the full groove. I will keep posting results.
I’ve had one engine with these installed and a new set around here somewhere.
 

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Had to file a notch in front bearing shell parting line to allow oil to lube the timing chain and distributor gear. Checked clearances .002 all 5 locations. Stock Cad500 thrust bearing. 1,2,4,5 have 270 degree Pontiac 455 bearings.Started engine and had 75psi cold. Backed off adjustable oil pressure relief valve to 50 psi at 650 rpm idle. Pressure 75 at 2500 rpm. Still testing, need to put full heat soak into engine water temperature. This is a hydraulic roller cam setup from Howards Cams. CadCompany 2.250 intakes for 120 cc heads. Larry Kruzik non adjustable shaft rockers. Also has a .875 i.d. pickup tube.
 

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455 bearing test engine. 512 cu in .060 over forged flat tops. PEP I-beam rods. Edlebrock intake 800 cfm holley spread bore. 120cc heads. Grooved cam bearings. Howards hydraulic cam and lifters. Rear sump 8 quart oil pan..875 pickup tube.
 

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Big Cadoo!

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455 bearing test engine. 512 cu in .060 over forged flat tops. PEP I-beam rods. Edlebrock intake 800 cfm holley spread bore. 120cc heads. Grooved cam bearings. Howards hydraulic cam and lifters. Rear sump 8 quart oil pan..875 pickup tube.
2.190 intakes 1.800 exhaust valves. Not 2.250 intake valves.
 

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Ran Pontiac 455 main bearings 1 hour on test stand. Blocked half of radiator to get 200 degrees water temperature. 30 psi at 500 rpm, 70psi at 2500 rpm. This test was done to compare 3.250 full flow main bearings vs other 3.250 partial flow main bearings. Oil pressure is higher but now there isnt full flow to rod bearings. As Ive Never seen a full flow Cad500 main bearing with signs of distress vs rod bearings that were wiped to the copper I will continue to use the full flow Cad500 main bearings and .875 i.d. pickup tube with the other oil system modifucations. Case closed.
 

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Years ago I bought a rear sump oil pan fron Larry Kruzik. It is a 425 midsump oil pan converted to rear sump. Workmanship is flawless. It is on my 516 Cad500. With SS300 hydraulic flat tappet there was never a oil pressure problem. When that engine experienced severe low oil pressure pressure with the mechanical roller cam one of the modifications I made was to weld a length of 2 inch exhaust tubing cut down its length in the midddle of the pans width as this pan was so close to rotating assembly it was kissing the h-beam rod bolts. I welded that to bottom of front section of oil pan along the bottom while on an engine block to prevent warpage and capped the front of tube. Then with pan removed I cut the inside of pan out 1.5 inch leaving a 1/2 lip on left side of engine looking to rear. I then bent that up towards crank to act as oil flow diverter to the rear sump. This was part of the
875 i.d. pickup tube modification.
 

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Years ago I bought a rear sump oil pan fron Larry Kruzik. It is a 425 midsump oil pan converted to rear sump. Workmanship is flawless. It is on my 516 Cad500. With SS300 hydraulic flat tappet there was never a oil pressure problem. When that engine experienced severe low oil pressure pressure with the mechanical roller cam one of the modifications I made was to weld a length of 2 inch exhaust tubing cut down its length in the midddle of the pans width as this pan was so close to rotating assembly it was kissing the h-beam rod bolts. I welded that to bottom of front section of oil pan along the bottom while on an engine block to prevent warpage and capped the front of tube. Then with pan removed I cut the inside of pan out 1.5 inch leaving a 1/2 lip on left side of engine looking to rear. I then bent that up towards crank to act as oil flow diverter to the rear sump. This was part of the
875 i.d. pickup tube modification.
I’d like to see a picture of that
 

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These are the best pictures I can take at this time. Cadmaro under tarp and cover roped down. The picture shows front end of tubing cap. The tube was cut to pan contour.
 

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