kbuhagiar

Hello, Folks,

I am in the process of prepping my engine to go back into my 63 convertible. I am curious about the engine pad. Mine has always been blank, but I wonder if it is because it has been resurfaced or if it had never been stamped. Can anyone tell from this photo if those are broach marks or just a pattern created from resurfacing? The other numbers on the block are:

GM 3782870
F2 63




Thanks in advance!

tentuna

My guess, belt sander, broach marks should be faint

philip964

check out the texture and broach marks from this thread.

http://forums.corvetteforum.com/show....php?t=2041727

Too me this is what it should look like, less the numbers. Otherwise its been decked.

Frankie the Fink

For my education, can somebody post a picture of a stamp pad with an arrow to a broach mark(s) ? I keep hearing them talked about but have no idea what they are or should look like. Should a '61 block have them ?

JohnZ

All blocks originally had some degree of broach marks - some were VERY faint and have disappeared with exposure, and some were more prominent and remain visible. Absence of visible broach marks is quite common on 30-40-year-old pads, and should not be used as the only criteria for evaluation of the pad surface.

The broach marks in Ken's blank pad photo at the top of the page look legit to me, as they exhibit the typical "chatter" in the direction of the marks; belt-sander duplicates typically have uninterrupted straight lines with no "chatter" marks.

Photo below is an original '62 pad, and shows typical longitudinal factory broach marks.

Frankie the Fink

Thanks JohnZ - another tidbit of knowledge to go in the old memory banks ! My car is supposedly numbers matching/original motor:

VIN: 10867S108523 (Built May 18th, 1961)

ENGINE CASTING: 3756519 Casting Date: D271 = April 27th, 1961
ENGINE STAMP PAD: 108523F0502CU (Flint plant, May 2nd 1961, 270HP dual quad, solid lifters). My broach marks are not clear at all, although this is a pretty poor photo:

kbuhagiar

Thanks for the info, John.

This begs the question: If not from resurfacing, why would the stamp pad be blank? Can application be determined based on the casting numbers (GM 3782870 F2 63)?

Shurshot

The block you have was probably purchased over the counter from GM parts. If you look under the starting pad mounting block as when the block is spun upside down you might find another number there.

JohnZ

Nope - most likely a Service replacement short block; the casting date code (June 2, 1963) says it was made at Tonawanda.

63 340HP

Tonawanda foundry blocks were date coded with a two digit year "F2 63." All Flint foundry blocks were a single digit date code, with a similar date reading "F2 3." Corvettes only came with Flint blocks, so the "63" code reflects that this block did not come from a Corvette.

The block may be from the correct date year & month, but it was cast in the wrong foundry for a Corvette.