New to forum and 7GCBC question

[AKpilot]

Hello, I'm new to the forum, and not very proficient with navigating these things.

I own a 1974 7GCBC, it has wood spars and I replaced the engine years ago with the LYC O-320 B2B, I didn't realize at the time that only the metal spar 7GCBC's were approved to have the 160 HP O-320 B2B engine. Does anyone have any experience with this situation? I assume I will need to get a field approval, but I've heard it's not as easy as it used to be? Any advice or info would be greatly appreciated!

 

[aftCG]

Looks like you might be right. ACA did the approval for 160hp with a serial number range that would include planes originally built with aluminum spars.
Not sure you could even install aluminum spar wings and get your plane to conform to the TCDS.

Did a quick Google search and found a 7GCBC thread with your exact subject and it seems field approval was how they made it legal.
And you're right, the good old days of 337 field approval are mostly gone. They sure are here in the upper left corner.

 

[Sully]

There is a Service Letter (SL-430 rev A) allowing earlier years to be upgraded to 160 HP but it does require metal spars.