Inside Micrometer

[c9zx]

4. Again, schmucks like me are stuck trusting our engine shops because if we check all of those tolerances, as I think we should, we are going to spend more time checking and less time assembling...and more money on gauges and such then on HP.

You are correct. For that reason it is critical you find a machine shop that builds racing engines, has experience building 351Cs, and has a consistently good reputation. You will pay a little more but, as you said in 4. above. And then there is the case where you check it, it is out of the tolerance specified but usable. What do you think the run of the mill machine shop is going to do for you? Granted finding the right machine shop may be problematic. However, it is a must to get the kind of results you seem to be looking for. Chuck

 

[droptop73]

Hi James, what I attempted to illustrate is, there is a difference between accuracy and comparison. As a machinist by trade I see a significant difference. Maybe I am just over thinking that as well. If you want to make good measurements you need good tools. A caliper is good to maybe .001 to .002" for accuracy and the inside measurement to outside measurement is rarely accurate even for comparison (good for rough dimensions only IMHO). A quality outside mic with a tenth scale is accurate to .0005" without climate control but for comparison purposes it can be good for .0002" depending on the operator and their ability to get a good "feel" on the mic. BTW don't worry about the carbide tips on a mic, they protect the mic and should not damage the surface being measured unless one is using the mic as a precision C-clamp. I agree with darkhorse a dial bore gage is the best tool to measure any bore.

 

[Wolverine]

I am beginning to think:

#1- Plastigauge is a waste of time and effort due to reliability reported by our 385 brethren, our experts here, and in a couple of engine building magazines. I could not find anyone confirming the accuracy of the plastigouge(spelled correctly)

#2- These instruments are just way out of my price range, unless I want to buy used, and then resell them. I don't just need a bore gauge, I need a mic as well.

I love beautiful equipment as much as anyone. But 25 engraved photo's of (who is the guy on the $20?) Jackson(???) feel very nice in my back pocket.