[ponchjoe]

I am buying a 67 LeMans with a rebuilt 326 and it has 092 389 heads installed. Was this a good idea to improve hp to a 326?
Thanks for any input
Joe

[Baron Von Zeppelin]

Sort of good.
The chambers might be a little bigger to drop the ratio a bit.
Valves are a little bigger too. iirc

092 had same valve size as 093 , but different springs.
326 heads usually had smaller valves than those.

[b-man]

The 1966 092 heads have a 68cc chamber to make 10.5:1 on a 389, 1.92/1.66 valves.

The 1967 140 2-barrel 326 heads are 62cc to make 9.2:1 compression also with 1.92/1.66 valves.

So it’s pretty clear that someone was using whatever they had on hand, the 326 lost some compression and some performance with the swap to 092 heads.

1963 & 1964 326 heads had the smaller 1.88/1.60 valves, 1965 - 1967 326 heads had the larger 1.92/1.66 valves.

When the intake manifold to head bolt pattern changed in 1965 to the final design all the heads were upgraded to the 1.92/1.66 valves. Previously the only pre-1965 non-SD heads with 1.92/1.66 valves were the 1963 - 1964 9770716 Tri-Power 389, 421 HO and GTO 389 heads.

[Baron Von Zeppelin]

I think Wallace racing.com has a calculator for CR ratio factors.
Don't know right off how much 6cc will lower CR but it should put it down into a real safe zone for cheaper pump gas grades.

I wouldn't worry too much about milking performance from a 326 engine.
Just a good smooth cruiser machine would be better in most cases.

Good info b-man

[Joe-Touring]

My 0.040” over 326 has 1967 400ci #143 heads on it. Should be a similar setup to you. Runs great, not a lot of juice, however. No idea what cam it’s got, moves the car pretty well from a stop, but not much top end. Still fun to drive.

From my research, there’s not a lot of great options for a peppy 326. I think you’re pretty much limited to pre 68 heads, most of the newer heads have chambers that are too big. You also want to keep the small valves to avoid shrouding. The pre 68 heads don’t flow as well, I believe Steve25 said the problem is mostly on the exhaust side.

Another option would be some custom KRE d-ports with small valves. But that’s $3k.

Really though if you have the heads off, a few minutes cleaning up the valve bowls apparently makes a difference. And if you’re gonna go that far, a Melling SPC-4 or -5 cam would probably be perfect. That’s my plan anyway.

[ponchjoe]

Thanks for all the replies guys. I’m a 400/455 guy so I was wondering why someone would do this. I do not have any more info on the rebuild yet. I do have a 400 or 455 that will eventually make it into the car so it’s just a temp engine