307 sbc head

[Murphy]

Could someone give me the casting number and conbustion chamber. Thanks

[brian schuetta]

Blue print specs on NHRA site or ask Billy Nees.

[Adger Smith]

Year & model??

If your looking for NHRA specs: http://www.nhraracer.com/
Go to the year and model specific specs.
For just General specs: http://outintheshop.com/faq/casting/castings2.html
Hope that helps

[Murphy]

Thanks big help

[Billy Nees]

Why would anyone in their right-mind be asking about 307 head castings???

[Dwight Southerland]

Originally Posted by Murphy

Could someone give me the casting number and conbustion chamber. Thanks

Depends on the year. According to NHRA specs '68-'69 used 3911032 or 3927185 with 65.5cc combustion chambers, '70 used the 3927185 only with a 63.3cc chamber (?), and '71-'72 used 3986339 or 3998991 with a 66.1cc combustion chamber. These are all small port heads, like a 283 head, and use 1.72" intake and 1.50" exhaust valves.

1973 is an anomaly. That year the 307 is shown using 333881, 333882, 3973493 and 3998993 heads. The specs also show 1.94" intake and 1.50" exhaust valves with the same 66.1cc combustion chamber as the '71-'72 heads. These are normally considered "350" heads with large ports and a wider combustion chamber. I could easily doubt that those are the correct production heads since Chevrolet did not use those large valves on small bore engines (except the '60-'61 283 high perf Corvette engines). Maybe another gift from the NHRA tech department and an errant data entry person. But, being legal doesn't always mean being "right".

[Billy Nees]

The 185 and 339 heads cc at more like 72-73 cc. I had a heck of a time getting my 339 heads down to the NHRA spec. of 66 cc. The 991 head looks to me like a 350 truck head and has an even bigger chamber.
The 73 heads actually do have 1.94 intakes, huge chambers and 350 style ports and IMHO are much too big to be considered for a STOCK 307. If you've ever driven a 73/307, they are real dogs.

[bubski]

Originally Posted by Billy Nees

Why would anyone in their right-mind be asking about 307 head castings???

Dime Rocket ???

[bubski]

Originally Posted by Billy Nees

The 185 and 339 heads cc at more like 72-73 cc. I had a heck of a time getting my 339 heads down to the NHRA spec. of 66 cc. The 991 head looks to me like a 350 truck head and has an even bigger chamber.
The 73 heads actually do have 1.94 intakes, huge chambers and 350 style ports and IMHO are much too big to be considered for a STOCK 307. If you've ever driven a 73/307, they are real dogs.

scraping your heads with a spokeshave to get to the proper cc's is a pain in the Arse for sure !! Better get an 85B n let it eat !!

[Billy Nees]

Originally Posted by bubski

Dime Rocket ???

That one ain't a "Dime Rocket".