[Pmseewald]

I have a 72 firebird with a 400 and I recently did a teardown. I was hoping if someone could tell me if the lifter bore walls look ok or if they have gotten to thinned out for a rebuild.

[tom s]

Can’t tell by looking,need to get them mic.Tom

[Pmseewald]

Other side

[Pmseewald]

Originally Posted by tom s

Can’t tell by looking,need to get them mic.Tom

Ok I will work on getting those. It's just some of the casting around the bores looks thinner than the others and I didn't know if it's from wear or if that was how it was casted.

[Pmseewald]

Originally Posted by tom s

Can’t tell by looking,need to get them mic.Tom

Ok I mic'd them and each bore is .80 inch to .81 and the wall thickness is between .17 to .18 inch.

[tom s]

I think they should be like .842ish?

[Pmseewald]

Originally Posted by tom s

I think they should be like .842ish?

Interesting. It's possible I may have messed up the measurement. I used a cheap caliper. Is that still within tolerance or should I be worrying lol?

[tom s]

Have someone with a bore gauge do them.Lifters are .842.Tom

[mgarblik]

If you want to check the lifter bores yourself, you can buy a precision pin gauge, or go-no go gauge. It's a quick and inexpensive way to see if they are too big or worn. Buy one .8435 size. If the gauge passes through the bore, it's worn pretty bad. If it falls right through, your in trouble. It should not go in.

https://www.mcmaster.com/plug-gauges...0-8330-0-9165/