It may be a 292 in a Merc, but the ECG heads are 55 -272  (switches like that were not uncommon during rebuilds) . However, there are varius suffix letters, which you did not include. "B & D"s which were std 7.6 compression as on  2 Bbl - 272s. Or  ECG-A or C which are 272 - 4 Bbl & 8.5 compression Power Pack heads. The last ones may be worth re building or up grading, but I'd suggest replacing the std heads with later ones.


Paul

I'm in Middle Tennessee.

It's a 292 in a '55 Merc.

You don't say,  what size is the engine?  If it's a 272, the 1.78s are likely fine for street use. On some heads, the bigger valves may be shrouded, somewhat, which somewhat offsets expected gains. You need to check for that.   As noted, unless you can improve the ports, you may not gain much. Also, porting Y-heads without a good handle of what works, may not get the results you expect. 


Paul

Dobie, where are you located?

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Yup, they do have the smaller ports. I was thinking of doing a mild port 'n polish along with the larger valves. The engine is stock or nearly so and runs OK. Been looking for better flowing heads but no joy so far, hence my question.

Don't the 55 heads have the smaller ports? I don't know if you would gain much by just using larger valves. You may be better off looking for some later heads.

Need to have my heads refreshed and while I'm in there I'd like to install bigger intake valves. The heads are 1955 ECG with 1.78" intakes. I'd like to go to the 1.92" intakes for later heads. Is there enough meat in these heads to do that? Any other issues I might encounter?