hey guys i took a set of heads off of and old motor i had laying around and to my suprise the first one was a matching numbers for a 305 H.O so that was all good until i took off the second one the numbers was not the same and when i look for info on the other part number i cant find nothing the h.o heads (416 ) and the other one is (418) but would a motor run with 2 diffrent heads on it ??

 

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It is never a good idea to run 2 different cylinder heads on an engine. Every head has different flow #'s, some have different size combustion chambers (different compression ratio), and even different valve sizes. This would make your left 4 cylinders run differently than your right 4...

 

the best thing you can do for an engine is to try and make every cylinder identical to the next one.head differences would benasty!

 

so nobody knows anything on the casting numbers 418 then ??

 

I know the 416's are just the standard 305 heads, but I've never heard of 418's...

 

the 416 are 305 H.O (l69) heads and they have 1.84/1.50 valves and a 58cc chamber with a 170cc runner
which makes them better than most other 305 heads but i think its the runner size thats diffrent thats all because i know that chevy casted 415,416,417,418 idk the diffrences between them as for runner sizes or anything if there is not diffrences that would explain why that guy rann the motor all these years with no probs