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they came with "186" casting number heads.........
The combustion chamber size of the heads with the casting number 376450 is 60cc. It is possible to install larger valves.
The chambers are 60cc. The heads are from 77-78 307 engine.
Find the casting number on them... type "GM (insert casting number)" into a search engine and you should find what you're looking for.
There 194 heads 1970 to 1980 heavy cast iron heads
Heads: Casting Number 3904390 - 1966-68 427, Intake 2.06, Exhaust 1.72, Closed Chamber, 98.4 CC.
This number will tell you what year and what moter the heads will fit.There are books put out for this purpose.
3998993 is from 72 or 73 307 or 350. 75 cc chambers.
If you have a 361 the 383 heads will work, but they won't work on a 318.
no you cannot they are not interchangeable the 89 heads are fuel injected heads and the 79 are carb heads and will not interchange
Actual olds heads casting numbers are underneath the valve covers
they could have either 1.94 intake 1.50 exhaust or 2.02 intake 1.60 exhaust