I just got a new 318 short block from mopar nationals this weekend i was wondering if i could put 360 heads on it some one told me to do that for more power or some thing like that he was talking real fast so i did not get what all he said

 

you will get better flow due to the bigger valves but will lose HP due to the comp ratio will be lower, depends on what pistions you have

 

i think there stock flat top pistions

 

would it be worth it then

 

its a toss up, what i would do is measure pistion to deck height, then do the math and see what you come up with, probly around 7.5:1, which wouldnt be a very powerfull engine. but with that low of compression you could add turbos

 

ok thanks

 

Is the short block complete? If it needs to be torn down, that would be the time to install some different pistons. Of course, you could always just trade it towards a 360 and not have to worry about this issue.

Edit: I saw that you already have a 360 in there. Get rid of the 318 and just build the 360. Or get another 360, build it, then swap it in.

 

yes it just needs the top put together i got the 318 cheap and my 360 smokes sometimes and sometimes it dont but i dont know why because it only has 93k so i was going to put my heads on it and drop it in but ill just do what you said ill try to get a 360 so it stays original

 

For some reason(s) that I do not understand, the cylinder heads on teh truck 318s and 360s need to be rebuilt about every 75,000 miles. Don't ask me why (well it's because the seals go and the vlaves need to be lapped) but they do. I'd look into that or trade teh 318 block for a set of 360 heads.

 

just change the cam shaft

 

if it smokes sometimes and some times not, more than likely the valve guides are worn.

 

See if you can find the later heads with the heart shaped combustion chamber ( LA heads, late 80s ) and get those done. I don't know the casting numbers, sorry...

j

 

Yep, or comp rings are starting to go.