Any of you Y-block gurus know which of the bolts shown are original? I have two engines torn down and they both have the necked down bolts without markings and some of the grade eight bolts. Who knows what's been done over the years but I'm just curious what's original.
Thanks.


'55 T-Bird
Battle Ground, WA

The ones with the unmarked heads are correct.  They are a grade 2 bold which is plenty strong enough for the job.  Ford and other manufacturers used grade 2 bolts in lots of places where they don't need the extra strength.  The grade 8 bolts are overkill in this application.

Thanks for that. Since I like symmetry and am building one engine from two I'll use all of the originals in this engine.

'55 T-Bird
Battle Ground, WA

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Wow, there is so much knowledge amongst this sites members!
Thanks all for sharing!

'55 T-Bird
Battle Ground, WA

The third bolt from the left with no markings on the head - that is your bolt!

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Interesting to note the "grip" area on the shank just under the bolt head. Looks like only the original Ford bolts have that self centering/alighment feature design into the bolts. 

64F100 57FAIRLANE500