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Dwight Southerland · 08-02-2015, 09:22 AM

Greg pretty well covered the makeup of the '65 model 327-250. To put some more perspective on the small block choices in a '65 full size Chevrolet:
1. 283/195 @170 Not totally bad considering you can use a 3-speed automatic now. You would have to want to chase this one because it is not favorable enough to be built cheaply. Obviously, it would be better if it were rated at 162 like in the Chevy II.
283/220 @ 217 auto Not totally bad either. This combo has been beat on a lot which means that to build a fast one will be expensive. Ask Wade Owens.
327/250 @ 251 This would be better at 245 like all the other applications in 1965. The parts are identical to the 327/300 except the carb. This combination has lots of development history.
327/300 @ 265 Like stated above, this engine is identical to the 250 hp version except carburetor. The 4GC will flow ~485-500 cfm while the AFB on the 300 version flows ~585-600 cfm. Is that extra airflow worth 14hp? I don't know. It has been my feeling that the GM AFB combinations need to be looked at again. The MoPar guys have made great strides in the development of the AFB's potential and that should cross directly to the GM engines. Also, you could make a case for using the aftermarket versions - Carter and Edelbrock - that have the same throttle and venturi sizes and pick up an additional 25-40 cfm.

All the 327 high compression engines from 65 thru 68 are basically the same except for carburetors, so you can do some comparisons there and make your own decisions. The 68 327/250 is different because it uses smaller port heads and less compression, but it has a Qjet and that is what attracts attention. Over the years as the combos have been sorted out the small heads have shown to be enough of a disadvantage that the power rating is down in comparison to the others. It's all about airflow, isn't it?

None of these combinations are a decide advantage over the selection of the 396/325 and none offer a cheaper solution. "You pays your money and you takes your choice", as Huckleberry Finn said.

08-02-2015, 09:22 AM	#73
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,001 Likes: 64 Liked 780 Times in 194 Posts	Re: 1965 Impala BBC Stocker Update Greg pretty well covered the makeup of the '65 model 327-250. To put some more perspective on the small block choices in a '65 full size Chevrolet: 1. 283/195 @170 Not totally bad considering you can use a 3-speed automatic now. You would have to want to chase this one because it is not favorable enough to be built cheaply. Obviously, it would be better if it were rated at 162 like in the Chevy II. 283/220 @ 217 auto Not totally bad either. This combo has been beat on a lot which means that to build a fast one will be expensive. Ask Wade Owens. 327/250 @ 251 This would be better at 245 like all the other applications in 1965. The parts are identical to the 327/300 except the carb. This combination has lots of development history. 327/300 @ 265 Like stated above, this engine is identical to the 250 hp version except carburetor. The 4GC will flow ~485-500 cfm while the AFB on the 300 version flows ~585-600 cfm. Is that extra airflow worth 14hp? I don't know. It has been my feeling that the GM AFB combinations need to be looked at again. The MoPar guys have made great strides in the development of the AFB's potential and that should cross directly to the GM engines. Also, you could make a case for using the aftermarket versions - Carter and Edelbrock - that have the same throttle and venturi sizes and pick up an additional 25-40 cfm. All the 327 high compression engines from 65 thru 68 are basically the same except for carburetors, so you can do some comparisons there and make your own decisions. The 68 327/250 is different because it uses smaller port heads and less compression, but it has a Qjet and that is what attracts attention. Over the years as the combos have been sorted out the small heads have shown to be enough of a disadvantage that the power rating is down in comparison to the others. It's all about airflow, isn't it? None of these combinations are a decide advantage over the selection of the 396/325 and none offer a cheaper solution. "You pays your money and you takes your choice", as Huckleberry Finn said. __________________