I came upon a pair of S/B Chevy Heads today that were "Freshened Up" and stashed away on a shelf in a Local Shop. They appear to be Runnable on a Stocker engine. Both are Date Coded E 10 8 & casting # 3917290 Show to be for '67-'68 307 & 327 Single Camel Hump No ***ecory Holes They worth A **** or just another set of S/B Heads ? Any Info would be Cool.
Check the size of the valves! Do they look big or really small... the space between them is a dead giveaway.
Exactly. If they have been re-worked and modified and the valves are really close together they might be 2.02 and 1.60 valves which might just make them worth something to somebody.
Very Small Valves. I am not to Hip on the Chevy Junk anymore, Guess I will let them Lay where they are.
Port sizes are smaller than the double-hump heads as well as the valves. If they're fresh and in good shape they're at least useable heads that don't have holes in them. If they're cheap, they'd make a good set of heads for a truck motor or something where performance isn't #1 priority. I'm putting together a low-buck 327 for my truck-I'd use those heads over the ones that I have (882's).
Desoto they are not worth much today but I recall tossing things like hubcaps and stock 4 bbl intakes that are worth a fortune today. If you can get them cheap they may be worth something in a year or two. I wouldn't wnt to give much for them but like I said if you can get them cheap.
The small valves are good for low end torque. The 64cc chambers will raise the compression about half a point ( I think) on a 350.
I'd have to go along with what they said. Low performance heads but if you can get them cheap enough they work ok on small displacement engines.
An old thread but might help someone. They are not 1967, they are one year only like 3917291. They are also 69-70cc heads, not 64cc. They are the heads used on 1968 307 or 327/250hp engines if they were built at Tonawanda. McKinnon didn't build 4BBL engines in 1968, so they only did 307 and these used 3911032 heads. Not sure what heads Flint used on 307 or 327/250hp for 1968. There is a lot of misinformation around those 1968 327/250hp engines, the same engine in 1967 appears to have used larger chamber 75cc heads and has a compression ratio of just over 8.5:1, which GM claim as 8.75:1. The 1968 4BBL 327 has the 69cc heads and is about 9:1 or thereabouts yet GM still publish it as 8.75:1. Funnily enough a 1968 307 with the same stroke and same heads gets correctly quoted as 8.75:1 which means the 327 has to be wrong as the extra bore give extra capacity into the compression calculation. The heads used in 1969 307 and 327 (210hp (small 2BBL) and 235hp(big 2BBL))are 3927185 which are the same thing but with accessory bolt holes in the ends. Funnily enough the 1969 327's are correctly quoted as 9:1. The only difference between a 1968 327/250hp (L73) and 1968 327/275hp (L30) is the heads, the L30 gets the 1.94/1.5 valve Fuelies (3917291 for Flint or 3947040 for Tonawanda engines) which is a 25hp gain for the larger ports, higher compression and bigger intake valves. There is also a slightly different advance curve, but that is it, same cam, same pistons, same intake, same carby etc. We got the L73 in Australia in the HK Holden GTS327, very similar size car to a 1968 Nova at 111" wheelbase. In proper tune running on Australian 97 Octane pump fuel these with an M20 Saginaw, 3.36 10 bolt rear and 14" D70 tyres would do a 15.2-15.4s quarter and reach speeds of 135mph, easily revving beyond 6500rpm. So the 250hp 327 isn't that bad of an engine for a small valve thing, and they really woke up if you changed the heads out for a pair of fuelies! But you started breaking Saginaws and 10-bolts.
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