3.9 heads on 3.5 block

bluepuggsy · Post by **bluepuggsy** » Thu Nov 30, 2006 6:17 pm

replacing heads on 3.5 block with 3.9 efi heads using 3.5 gasket.will it be ok.slight over hang of the gasket at the outlet port, will this be a problem. has anyone used these heads on a 3.5 and was it ok

Post by **Coops** » Thu Nov 30, 2006 6:35 pm

when you say outlet port what are you reffering to mate???

i have used 3.9 heads on 3.5 's ok
as same heads just later castings,

bluepuggsy · Post by **bluepuggsy** » Thu Nov 30, 2006 7:23 pm

the o ring on the 3.5 gasket is 3-4 mil smaller than the 3.9 gasket so is closer to the valves, but as you have done this i hope im ok

Post by **katanaman** » Thu Nov 30, 2006 9:12 pm

Don't go with the marks on the head as a 3.9 gasket will naturally have bigger bores to the 3.5. As Tony said they are the same head unless they are very late ones. I would recommend you get a light skim done on the heads just in case any slight depressions from the old gasket cause problems. Its never a bad idea to skim heads you don't know the history of anyway and means you start of with a good basis.