[tom s]

Egge also has 8.6-1 389s but still close to $800.Tom

[b-man]

Cheap 389 pistons just don’t exist anymore unfortunately.

If you’re lucky enough to find some NOS 30-over dished factory pistons for a decent price it might be possible, but the search may be a long one that may never bear any fruit.

I would say bite the bullet and get some custom Autotec forged dished pistons and just resign yourself to buying the one expensive item needed to make this project the most viable. I paid dearly for the 27cc dished Ross forgings in my 421 build to get 8.8:1 compression. My goal is as to enable my heavily optioned factory air conditioned convertible to run in 91 octane 10+% ethanol premium unleaded in the hottest summer weather without issues.

I didn’t like spending $900 for custom pistons but that’s what it took to get where I wanted to be. The 389 and 421 engines running original heads really have no other choice.

[MarkS57]

FWIW, if you're going .030 over why not go .060 for a 400 piston? My first engine job I did was a 62 389 and I punched it .060 no issue. The later 389 blocks suffered from thin walls but not a 62. Do you suspect you'll ever need to rebuild this engine again? This should get you to mid 9's at less than $600. With these, the top ring gap is critical.

https://butlerperformance.com/i-3015...tegory:1394344

On the other hand, another $300 will get you a custom piston exactly as you want.

[Goatracer1]

I considered a 400 piston but I hate to take a virgin 389 block and bore it the limit. I have just found that Kanter has 389 standard and +.020 dished pistons in stock at a reasonable price. They also will have +.030 and +.060 in a couple of months. Thanks for all the suggestions.