ZD75blue

Hey guys...

I'm hoarding... err buying parts for the rebuild of the 75's 350. I'm going to do a mild hop up... a little more then the 165 stock hp. New cam, headers, etc.

Which brings me to my question on jegs web site, they have 3 types clevite part numbers H, HD, and P. http://www.jegs.com/cgi-bin/ncommerc...43&prmenbr=361

H- High performance bearing.
HD- High performance bearing with dowel hole.
P- Greater degree of change in wall thickness. Steel backed bearings with an intermediate layer of copper/lead alloy and electro-plated lead/tin/copper overlay. Precision undersizes are not resizeable.

My question is... what is a dowel hole? is it something used to align the bearing? Oil passage? :confused:

ZD75blue

On the same note... I've read that the Pistons that got installed at the factory are crap... And that if you ever plan to use nitrous or anything else for that matter they will melt.

Can anyone recommend a decent brand, Federal-Mogul has been around for a while, and they are cheap enough. :steering:

70BBvert

Not sure about the dowel hole. I usually let my machine shop spec out the bearings & rings. I assemble the engines myself also. Anyway I wouldn't buy parts ahead of time, wait until the block is disassemble & the crank is re-worked if necessary. If the crank needs to be ground undersize you'll need a different bearing size.

I used Clevite 77 & sealed power rings on the last two buildups, bearings were P part #. Pistons depend on how you anticipate running the car, and nitrous, super charging, turbo charging. For a street motor hypereutectic or forged are resonbly priced.

Hord the cash - don't buy anything specific until you have a plan in place & the engine has been disassembled & evaluated.

Just my $.02

Jim

Flareside

You buy P or H bearing depending on the crank that you're using. P for most stock GM cranks. Aftermarket cranks usually have more metal at the journal to counterweight junction (the "filet"), so you need a bearing that is clearanced at the edges to match. The H bearings encorporate that clearance.

I think the dowels are to keep the bearings from spinning, but I've never seen a Chevy block that used them.

gkull

Flareside types faster than me!:)

You don't have dowl pin crank saddles. The "P" are perfect for performance and long lasting. The "H" are hard for racing and frequent bearing changes. Not required on small blocks till 600 hp.

It really comes down to your crank shaft type. "H" bearings are made for large radiused crank throws. Which are your better forged 4340 high hp cranks

gerry72

Dowels are commonly found on aluminum rods. Never saw a steel rod with a dowel.

ZD75blue

Thanks guys... i left the motor sitting to long while stripping it down... 6 months and its got some rust around the rings. So i'm brain storming while its got penetrating oil in the bores :(

Thanks again guys

ZD