Big Block Main Bolt & Oil Pan Bolt Hole Location Blueprint

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PROSTOCKTOM

PROSTOCKTOM

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Before I spend hours on the mill plotting all the holes I thought I would inquire if anyone has this information, or if anyone can direct me to the information?

I am planning on building myself a girdle this winter, so figured I better start inquiring now.

Thanks,
Tom
 
The main bolt locations are going to be more accurate block to block than the oil pan bolts. The through hole oversize you make the holes will usually compensate for the variances in the plus/minus machining tolerances.
 
The hard part is getting the eight longer main studs needed, 440 source has them at 16.95 ea
 
OLDSTYLE said:
The hard part is getting the eight longer main studs needed, 440 source has them at 16.95 ea
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Personally I wouldn't use any hardware that 440 Source sells in my engines. ARP has any size stud available that one could ask for. Their catalog doesn't even cover 25% of the items they actually have available if you call them.

Tom
 
CNC-Dude said:
The main bolt locations are going to be more accurate block to block than the oil pan bolts. The through hole oversize you make the holes will usually compensate for the variances in the plus/minus machining tolerances.
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I am used to making mold and die parts, so you can assume that my tolerances will be much closer than anything that is available for purchase from vendors.

Tom
 
That's the problem with trying to make products for older, non-CNC manufactured engines. They are made with such sloppy tolerances, that you end up with parts that don't fit a lot of blocks or heads because your parts are made with more precision. I've been down that road for over 20 with Chevy, Ford and Dodge. The newer engines like the LS, Hemi's and Coyotes are much closer tolerances and easier to make parts for.
 
CNC-Dude said:
That's the problem with trying to make products for older, non-CNC manufactured engines. They are made with such sloppy tolerances, that you end up with parts that don't fit a lot of blocks or heads because your parts are made with more precision. I've been down that road for over 20 with Chevy, Ford and Dodge. The newer engines like the LS, Hemi's and Coyotes are much closer tolerances and easier to make parts for.
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Been down that road everytime I make something for an engine. I play with AMC engines and the actual block blueprint has a +/- .010" on the dowel pin holes. Now that is some messed up tolerances.

Tom
 
Sounds like we both like a challenge! I'm sure your girdle will be well planned and thought out nicely.
 
Hmm, well if I was doing it for my own block then I'd plot the block I was going to use. Can't get any more accurate than that.. I wouldn't even consider using someone else's measurements.
 
Obviously I am not finished with the design, but at least I've got a good start on it.

20220901_114913.jpg


Tom
 
PROSTOCKTOM said:
Been down that road everytime I make something for an engine. I play with AMC engines and the actual block blueprint has a +/- .010" on the dowel pin holes. Now that is some messed up tolerances.

Tom
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Yeah, and a .020 window would be nice. I’ve seen them off more than that.
 
Once I'm happy with the scraper fit and location, I dowel them to the block. They go back in the exact same place every time.
 
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