Why can't we use Pontiac rod bearings?

Both use almost identical rod housing and crank journal sizes. The stock BBB rod measures .925" in width (front to rear when installed) and the bearing measures .826" in that same dimension. This means there is .090" total rod width that is unused - that part of the rod has no bearing inside it. The BBP bearing measures .886", so it's .040" wider than the BBB bearing. It would be .020" wider on each side, or stated another way .020" closer to the rod edge on either side. Maybe the tang doesn't center the bearing accurately enough and some part of the bearing would hang out the side? Maybe the crank journal has too much chamfer?

 

The tangs are the same I use Pont. rods with Buick bearings.
Bob H.

 

What are the modifications to use the pontiac rods?

 

I had a machine shop narrow mine so they would fit on the journals. I have since been told there is no advantage to running the Pont. rods. You have to be careful with your deck height. If your block has been decked there could be a problem.
I have by accident ( no rev limiter ) spun my 455 to 7300 rpms with no disaster but I may have just got lucky.
Bob H.

 

Yeah because I want to use the pontiac Hbeam rods for some added protection.

 

I know the Pontiac rod is a little longer(.025 i believe) and is a stronger rod so what was done on the wrist pin side and did you use Buick pistons?I have a set of Pontiac rods i thought of using but now i am thinking alum. Pontiac rods to save weight.

 

Yes I use Buick pistons. To be honest I can't remember the pin sizes. I do know that we machined the small end to accept Mopar pins and was goingto run Mopar pistons but chickened out and went with Jahns pistons. We had to bush the small end to get back to the Buick pin size. I think the Pont. pin is the same size but wouldn't swear to it.
Bob H.

 

"Cat" makes a nice Pontiac H-beam rod 6.625" long. These are way better than a 100k mile reconditioned stock rod.

They go in fairly straight forward…

The 0.0250” longer rod will place the piston higher in the bore and does have to be accounted for.
In most cases a much smaller cut off of the deck will be required to get the “quench” right.

They must be narrowed slightly to fit the Buick crank pin.

The 7/16” cap screw bolts may have to be “clearanced” with some very slight dolly work on the stock pan.


Also, when putting together a rotating assembly plan ahead.

There are many good "tapered" pin options available for the Chevy and this is a good place to save some rotating weight.

 

I think AM&P narrows the CAT Pontiac rods for use in a Buick and has them for $550. IMHO they're money well spent. You either get about a 1/2 point more compression or have to cut your deck .025 less than you normally would to get the compression you want.

 

Thanks for the info as all i can get is better.Now i am getting some where and hope to start the build in a month or two now it's time to make a decision as to put it in my Chevy LUV or in my 66 Sport Wagon.

 

Pontiac H-beam rod with Buick bearings. The tang has been moved over .030 so the bearing doesn't hang out of the rod.

 

Ditto...Automotive Machine and Performance (AM&P) can take car of your needs. :TU:

 

Interesting... you point out the "tang" has been moved, and there is a mysterious orange slice in the background...

Sorry, too much coffee today!ou:

 

No the tang is not removed, the slot in the rod for the tang gets moved over.

 

So here's a question for you..

If you going to replace the rods, why would you not go with a BBC rod, and offset grind the crank? And then use the Eagle H-beam BBC rods which retail for around $480?

You end up with a touch more stroke, and more favorable size rod journal, Easier to find(and a much greater selection of) rod bearings, in addition to a rod that is rated for 800 HP?

Benefits, in my opinon, certainly outweight the extra cost of offset grinding the crank.

JW

 

Jim I agree with prefering the 470. But you can use pontaic rods to save more money the cost of custom pistons for the chevy rod plus the cost of wideing the rod journal is a couple three hundered more than the 464 combo with a pontiac narrowed rod. My grinder hits us pretty good for the widening not the offset he says it takes him more time to widen than does the offset. When I first got out of college I ground cranks for 9 hours a day 6 days a week for like 6 months, I know I hated that job.

 

So to use Pontiac Super Duty rods I would have to narrow the rods a little? anyone know how much?
I have this build in mind as I have most of the parts already
SD rods
SP4 cam
T&D rollers
Stage 2 alum heads
Ross 10-1 pistons (Floating)
TA Sp1 intake 1050 Dominator carb
MSD ignition
Question would I have to have the piston pins changed for the SD rods? I now the SD rods were done a lot in the past. Anyone know the small end size of the SD rods?

 

I believe the wrist pin end of the Pontiac rods is .990 and would need to be opened up to allow a pressed Buick pin which is 1.00. If a stock size Buick crankshaft is used, you would need to narrow the Pontiac rods to the stock Buick thickness, this would be about .925.

 

It's .980.

 

as stated in an e-bay ad.

YOU ARE LOOKING AT BRAND NEW EAGLE CONNECTING RODS. THEY ARE H BEAM RACING STYLE THEY FIT MOST PONTIAC V8'S 350 389 400 428 455. THEY WILL FIT BUICK 400,430,455 WITH MINOR MACHINE WORK. THE PART# IS CRS6625P3D CENTER TO CENTER LENGTH IS 6.625" THE BIG END DIAMETER IS 2.375" THE PIN BORE DIAMETER IS .9810" THE BOLTS ARE ARP. 8740 WITH 190,000 PSI. THE WEIGHT IS 760 GRAMS. THESE RODS ARE BRAND NEW AS YOU CAN SEE IN THE PICTURE SEVEN OF RODS STILL IN THE BAGS I ONLY REMOVE ONE FOR PITCURE. THEY WILL FIT MOST PONTIAC V8'S MOST YEARS CHECK APPLICATION. THEY WILL FIT BUICK BIG BLOCKS 67 THUR 76 400,430,455 V8 IF YOU BORE THE SMALL END .003 BIGGER AND THE SIDE CLEARANCE NEEDS TO BE MILLED .005 BUT YOU NEED TO RECHECK YOUR MEASUREMENTS. THANKS FOR LOOKING AND GOOD LUCK.

link.

http://cgi.ebay.com/ebaymotors/PONT...094QQitemZ180339757094QQptZRaceQ5fCarQ5fParts