[Skip Fix]

400 I'm building is going to be a stick. Crank pilot hole measures roughly 1.00, 455 crank I just measured is 1.00. The pilot bushings and bearings I see are listed at 1.093 as well as the Dorman I have.
I know a .090 press fit is a little tight!

[John Milner]

This is the pilot bearing I have always used. It is a National 7109.

https://www.summitracing.com/parts/ntl-7109

This bearing fits in the second machined area and not the deepest one.

[mgarblik]

BOP Engineering sells the exact bearing you need in the Pontiac size. It's just slightly different than the 7109, which will work in a pinch.

[John Milner]

Pontiac used the 7109 (907321) bearing from the factory. I attached a NOS 7109 (907321) bearing picture and a copy of a Pontiac service manual for reference. Believe the one BOP sells is a 7109 as well. It does appear to have the same specifications as the National I listed. Wade’s appears to be cheaper in price so that is a good thing.

[mgarblik]

Originally Posted by John Milner

Pontiac used the 7109 (907321) bearing from the factory. I attached a NOS 7109 (907321) bearing picture and a copy of a Pontiac service manual for reference. Believe the one BOP sells is a 7109 as well. It does appear to have the same specifications as the National I listed. Wade’s appears to be cheaper in price so that is a good thing.

That's good information. There must be another bearing number that is very close that many parts stores sell that doesn't quite fit right. It is slightly smaller, just a few thousanths on the OD. It will be a slip fit and often spins in the crankshaft. This can make noise and ruin the crankshaft counterbore over time. Just a heads up.

[Skip Fix]

Thanks I was looking at the deepest recess -and tough to get that deep had to use a snap gauge. I didn't not measure the outer one I look at that 7109 specs above looks like a 1.3780 OD I'll see if that goes with my crank.

[mgarblik]

The new bearing should go in with a light press fit. .0005"-.001". Some people stake the edge of the crankshaft in 3-4 places so it can't walk out.

[OG68]

New Departure 7109.

[Skip Fix]

Chevelle 12 bolt I pulled part to use in the 65 GTO had Hyatt bearings.

[Skip Fix]

BOP one on the way.

[Skip Fix]

BOP is about 0.001 too loose. Trying one form Oreily and Summit

[Held for Ransom]

What one did you get from BOP?
I can't believe an SKF BR7109 isn't correct, or National 7109.
Shield on one side (goes outward, towards clutch), open on other (goes toward crank).
6202 has shields on both sides and is wider.

[John Milner]

I know it sounds a bit crude, but Pontiac staked the crank in a couple of places to help retain the bearing. My factory 4 speed 76 Trans Am engine was done this way. I have done this along with using some green loctite on the edge to retain the bearing.

[Skip Fix]

it just says 7109 on the one from BOP. Oreilly one should be in today. Is there a plain bushing? Ames has one listed.

[Held for Ransom]

Did the BOP unit come with a shield on one side? Looking at Butler, it looks like a no shield bearing. https://butlerperformance.com/i-2445...-bca-7109.html

[Cammer-6]

or use loctite made for bearing setting(green)

[Skip Fix]

Yes the BOP has a sealed side and an open side. Picking up one bearing and a bronze bushing tonight and going to mike them all.

[Skip Fix]

Got a bushing and another bearing (Precision) at Oreilly and got out the mike
BOP shielded one side 1.3773-easy to pull out
Precision open both sides 1.3777-easy to pull out but a little snugger
Dorman 690-023(has other numbers stamped on it) Bushing 1.3792 Feels a little snugger but there are some sharp edges at the chamfer for the input shaft I want to hit with a jeweler's file before I see if it is snug

I think the specs published are supposed 1.380

[John Milner]

Curiosity got the best of me so I measured one of my extra 7109 bearings and a 428 crankshaft. Used a snap gauge and calipers to measure the crank. In the past, I have always had to lightly tap mine in. I’ve staked the crank and have used some green loctite just to be safe before. But have also ran them without doing either. Have used this bearing probably 6-7 times in the past. This particular bearing isn’t loose in the machined area on this particular crankshaft. Definitely odd that yours drops in like that with no resistance. Maybe there will be a bushing that will get the job done for you.

[Skip Fix]

Summit's is a National Bearing 7109 with PEER and China stamped on it. Sealed one side OD 1.3775