54 stamp pad and numbers

[Tim E.]

Re: 54 stamp pad and numbers

Randy - Now I feel bad...certainly didn't mean to contribute to ruining anyone's day! As I recall, the internal difference had to do with the internal pressure oiling passages. I'll see if I can re-locate the documentation. I'm interested in it now too (since I now have two 911 blocks...one F54Y and one F54YG). Tim

[Tim E.]

Re: 54 stamp pad and numbers

The 3 items I found are:

1. Corvette 3935911 blocks have larger cam journals than the passenger car version. Don't know what "larger" means....no measurements provided.

2. Corvette 3935911 blocks were not cross-drilled for hydraulic lifters. It was not mentioned where the cross-drilling was done in order to observe it.

3. Oil filter line connections larger than 1/8" NPT indicate a conversion to "full flow oiling". I have measured mine to see what I have and it isn't clear if this is really a difference between the two 911 blocks or a difference between a 235 and a 261.

I intend to look for these differences between my two blocks this weekend and will report back.

Tim

[Dan P.]

Re: 54 stamp pad and numbers

look at the the backside of the G's. The one in quastion is a round back like the ones in a letter set . The original ones have straight flat back not curved.

[Tim E.]

Re: 54 stamp pad and numbers

I compared two 3835911 blocks this weekend, one with a stamp pad suffix of F54Y (Passenger Car) and one with F54YG (Corvette).

The only difference I could find turned out to be very evident....the cross drilling of the lifter bores. On the F54Y block, a 5/8" hole is drilled from the back of the block, directly above the rear freeze plug, horizontally through each lifter bore. A plug (similar to a freeze plug) seals the oil passage at the rear. This facilitates the use of the hydraulic lifters used with the F54Y block.

The F54YG (Corvette) block does not have this cross drilled hole nor the 5/8" plug.

Reference the attached photos:

First photo - The plug is clearly visible on this view of the F54Y block from the rear directly above the large freeze plug.

Second photo - The cross drilled hole is clearly visible in each lifter bore.

Third photo - No hole is present at the rear of this F54YG block in the same location above the large rear freeze plug.

Hope this information is useful in differentiating the F54Y and F54YG versions of the 3835911 block.

Tim