Looking at a 170a missing FWF. What fwf is compatible?

[imncntrl]

I am looking at a 170a missing the firewall forward. I haven't gone to look at it yet and was wondering what my options are before I do. I see several 170b FWF's for sale. Would it be mechanically compatible and type cert. compatible?
thank you

[Bruce Fenstermacher]

There are several changes firewall forward from the A model to the B model depending on what B model. Not with the engine or accessories bolted to the engine however with the exception of the mufflers. As for the mufflers the early pancake style could be used but most wouldn't cause the later Hanlon Wilson style is approved for the A. You should know however with the Hanlon Wilson style the setup you want is from a '52, the '53 and later is different but usable depending. Oh and the mufflers are not 172 mufflers which are bigger.

The differences really are in the installation. All of them can be replaced with the early A setup or the later B setup used in the A. Your approval would depend on what upgrades you incorporate and the view of your IA of what is a major and minor alteration. For example if you got the later B model 3" scat muffler shroud heat setup and wanted to incorporate that rather than the 2", that might be considered minor. If you wanted to use the later '53 and later pressure cowl baffling rather than the internal pressure box, that might be thought a major.

BTW if you find a o-300 C or D installation, the Association has the STC to make that legal on the A.