A post in Chevelle Tech got me wondering.

My old 327 had these heads with the tiniest looking valves I had ever seen. I mean small!!! Probably not the original heads since my 65 was an orig 283/PG car and the 327 was .030 over. But maybe they were the 283 heads. Who knows http://www.chevelles.com/forum/confused.gif

I sold them long ago so I don't have casting numbers. I was just curious what was the smallest valves put in small blocks?

Thing was still pretty quick for a P.O.S. 327 http://www.chevelles.com/forum/smile.gif

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Team Chevelle Gold
1965 406 6speed
1998 Tahoe LT 4x4
My Web Site (http://huhwhye.tripod.com/mypersonalsite/index.html)

The smallest valves I know of are 1.72 intake and 1.5 exhaust. I've pulled 186 castings from a 235hp 327 and a 69 350 C-20 truck which had those valves. I read that 186s were good performance heads, which goes to show that Chevy head casting numbers don't guarantee cc volume or valve size. The smaller valves are also on a lot, if not all, 307s.

Back in the late 1950's the quickest car around was the 1957 Vette with the 283HP FI 283 a close ratio T10 and 4.11 gears.In a reprint of an magazine article I have shows an especially quick one with a curb weight of 2985... totally stock running 14.3 @94 MPH !!
Those engines had 1.72 X 1.50 valves.They were enough to send those 097 Duntov cammed 283's right to 7000 RPM.

They were also used on all 265 and 283 engines from 1955 to 1960.The 327 used them on HP rateings of 210,235 and 250.To my knowelege all 307's came with 1.72 X 1.50 valves.

For engines of that size in normal passenger car / truck use of the day they were perfectly fine for idle to 4500 rpm ranges with stock low hp hyd cams.



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1969 El Camino
69 LS1 335 HP 427
( not the origional engine)
M21 12 Bolt 3:07's.
Daily Driver work truck.

I had that 327 dynoed and it made 219hp at the wheels, I 253tq. Car ran strong in the mid 14s. Better than most of the guys back then at the local track.

I always get them mixxed up but either the 262 or the 267 had 1.72"/1.38" or 1.40" valves b/c the 3.5" bore was soo small.

Also the little 315hp/283 fuelie engine had 1.94"/1.50" valves whereas the 290hp/283's just got by with the little 1.72" intakes...

AND that old-fashioned -097 little Duntov solid cam is a winner in my book today, even if there are better, newer solid cams for the little engines! pdq67