[RAIV55]

I was on the Mahle site this morning looking for pistons for a SBF. Came across this news release. Only one question, what's a big block Pontiac?...

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6/10/2008
H-Series Performance Rod And Main Bearings Now Available For Pontiac V8, 421-428-455, 1963-1976 Engines [PDF, 60KB]


Mahle Clevite Inc. is proud to announce new High Performance H-Series Rod and Main Bearings for Big Block Pontiac engines. These new rod bearings are narrowed on one side for increased crank fillet clearance and don't contain any dowel holes. The main bearings for positions 4 and 5 are full annular grooved, bearings for position 1, 2, and 3 have grooved upper halves and plain lower halves.

421 CID (6.9L), Pontiac V8 cyl, 4.094 in/104mm Bore, 1963-1966 428 CID (7.0L), Pontiac V8 cyl, 4.120 in/104.6mm Bore, 1967-1969 455 CID (7.5L), Pontiac V8 cyl, 4.151 in/ 105.4mm Bore, 1970-1976

Part Numbers
CB-758HN STD, X, -1, -10
MS-667H STD, X, -1, -10

Pricing and Specifications
See current price list and performance catalog.

Interchanges
Federal Mogul Rod Bearing Set 8-7050CH
Federal Mogul Main Bearing Set 151M

If you have any further questions, please contact your local MAHLE Clevite Inc. Representative, a customer service representative at 800-223-9152 or Jeff Schaerer, Product Manager, Bearing Product Team at 800-338-8786.

[ho428]

You know, the way you and they worded that you could just about say the 3 1/4" main is the mysterious Pontiac big block.
Not exactly what we all think small vs big blocks, but vs the 3" main block you could.

[Mr. P-Body]

The rod bearings are the same number as the Clevite, and probably the same bearing. Nothing "new" about them. Been around for many years. Mahle has been making some "noise" in the American market of late.

As for the "big block" thing, it's pure ignorance of the Pontiac and it's design parameters, and a lack of research into the market that causes this. There ARE "small journal" and "large journal", but the word "small" is relative... Except the 265/301, they're ALL the same "size".

Jim

[mikeb]

I've had better luck with the el-cheapo generic federal mogul rebuilder bearings... the last set of clevite 77 bearings I tried ate a crank.

[RAIV55]

Originally Posted by mikeb

I've had better luck with the el-cheapo generic federal mogul rebuilder bearings... the last set of clevite 77 bearings I tried ate a crank.

We build about 50 engines a year, mostly racers, plus do a lot of machine work for do it yourselfers. Bearing failures are usually the result of something else wrong. We've had good luck with both FM and Clevite bearings.

[Mr. P-Body]

Agreed with RAIV55.... But "luck" isn't the operative word. Clevite "H" series and FM "performance" bearings are among the best out there. UGLY, but very good.

In general, the "harder" bearing like the Clevite "77" will not tolerate debris nearly as well as the softer "stock" bearing. If everything is completely "clean", they do much better on the cast crank.

FWIW

Jim

[65nss4spdGTO]

From what I've found on large journal mains, the race FM bearings are about .020 narrower then the standard Clevite bearing, I haven't compared the race Clevite bearing.