I recently learned that Chevrolet had a "new" 250 HP 327 engine for their '68 Full Size models. It seems like they call it a "Regular Gas" engine and it looks like the compression ratio was 8.75 instead of 10.00 in the regular 275 HP 327.

But finding out details about the engine is a little hard to locate. I'm trying to find out what carburator it had, if the heads were unique to the engine and how many of these engines were made. (I'm going to guess that it had 307 heads).

Any info would be appreciated, as well as anything extra anyone could add.

Bill

The power reduction came from the lower compression ratio (for regular fuel) and small intake valve (same as a 307)....but they were not 307 heads as a 307 head on a 350 would no longer be a low comp. head). They used the stock Quadrajet Carb. Around here they were fairly common as they could use reg. gas.
I had that engine in more than one Demo. Overall performance was good but you could tell that there was less power when wound out through the gears. Like over 4000 RPM.

Gene,

Was the carb the same CFM as the 275 HP carb? Also wondering if you could tell one by the head markings or what other way was there to tell by just looking at one other than checking the Engine Suffix Code?

Thanks

Bill

Bill, Carb was the same CFM. Can't tell you on the head markings, its too new for me.

<<<<>>>>

Hi Bill,
That '68 327-250 reg gas was just a pinch above the dog 307-200,imo.Nobody wanted the 327 250 motors for anything other than to run in their winter salt rat cars<g>.The heads were terrible from a performance standpoint.As Gene stated,the intake/exhaust valve size was 1.72/1.50 these were low compression heads very similar to the 327-275 head except for the small cc mod to accept the 1.72 intake valve.The 327-275 had the 1.94 intake valve.
It is always best to ID a cylinder head by the casting number.The cast# for the low-po '68 pass 327-250 is #3917293.Externally,these heads had a slightly taller double rectangular "humps" than the better 327 1.94 heads.
Hope this helps,Jimpala

Jim,

Appreciate the Casting Number and additional info. I have seen those head markings before and didn't know what they meant. I'll be paying more attention to '68's now when ever I see an original.

I have noticed in my books that the Engine Suffix Codes on them are HN and HK (They listed 2 even tho there was no description difference between them. Both stated Regular Gas, Powerglide).

Bill