84_302

I have 289 heads on my 302. Bought it like this. What are the pros and cons? I have a setof 351W heads I could put on it? whats the pros and cons about them? Another question, is there anything I could find the longer of the two bellhousings that were made for the c4 transmissions on?

Thanks

my77stang

if the 289 heads dont have hard ex seats the valves are going to pound themselves into the heads which is bad. otherwise, they are small chambered heads which is worth a bump in compression.

what year 351 heads? C9OE / D0OE heads are a definate upgrade, similar to GT40 heads, but again they would need hard ex seats installed. later model 351 heads are the same casting as 302 heads and are worthless.

84_302

how do i know if they had "hard ex" whatever you said ... if they where hitting the heads wouldnt i hear a tick or knock? I dont hear anything and I think the 351 heads are 1979 so those wont be put on... Where can I find whatever you need to put 1970 351w heads on my 302?

my77stang

you'd have to have the 289 heads off the car to see if they had hard seats, and to make 351w heads work on a 302 you need nothing but some grade 8 washers to go under the heads of the head bolts (351's have a larger hole in the heads). if your going to go hunting for early 351w heads, you might as well go hunting for GT40 heads because they are easier to find, dont need hard seats, and flow a little better anyways.

84_302

I see... arent the 351 heads a alot ceaper then the gt40's? another question what can you usually find the longer of the 2 bellhousings that came on the c4 on? i need one

mjr46

the only 70's or late 60's heads worth having as an upgrade are c9oe or dooe heads as mentioned, your 289 heads may be better depending on which chamber they have, if they have a heart shape combustion chamber and are ported and have bigger than stock valves they'd be worth using built right, best way to see what you have is pull them and inspect them