302 heads ?

[tjgp360]

starting next week i will in the process of installing a new camshaft, from what i understand the stock 360 has a horrible Compression ratio but my question is how well will the 302 heads work to boost compression?

I have searched the internet for hours and i haven't found enough information concerning 302 heads on the 360.

Now i understand that the small valves on the 302 are not good at all for breathing or higher rpm's and i am willing to enlarge them for better flow.

but it seems like many people are against the swap even with the enlarged valves....... and THAT is what puzzles me, why?

wouldn't valve work allow them to flow just as well as j heads?

oh and by the way this is my cam

http://www.summitracing.com/parts/SUM-K6901/

 

[Coronet 500]

It's argued maybe an increase of .5-.75 compression points. Here is some discussion about this subject.http://www.forbbodiesonly.com/moparforum/showthread.php?t=17176

 

[Coronet 500]

Here are some numbers. http://www.shadydellspeedshop.com/moparheads.htm

 

[tjgp360]

Thanks C-500 but in that first link, if i followed it right i think they were talking about it on 318...im under the impression that the heads have a different result on a actual 360.

i want to bump compression to at least 9-1 without choking it down in the higher rpm's.... if a head swap can even get me close to that goal than im all for it, im just in no position to rip the engine out of my daily driver lol

 

[Coronet 500]

Yes, 318's. Your options are basically port and valve 302's, cut your J's .050" or buy X heads or Edelbrocks. The cam you picked is a great street cam. My opinion the worked 302's (not all out porting) will give you great velocity and throttle response but restrict performance if you go with a bigger cam.

 

[tjgp360]

Yes, 318's. Your options are basically port and valve 302's, cut your J's .050" or buy X heads or Edelbrocks. The cam you picked is a great street cam. My opinion the worked 302's (not all out porting) will give you great velocity and throttle response but restrict performance if you go with a bigger cam.

ok great! i think i will go that route but im lost when it comes to valves......is there a possible diy solution? today i called a engine shop asking how much to change my pistons and he told me $800 :thebirdman: that

i can spend a little under 200 on pistons and change them in a weekend lol soo i rather cut out the middle man and do the work myself if possible

 

[tjgp360]

Oh and do you have a recommendation on what thickness i should use for the gaskets?

 

[Coronet 500]

The 302's have 3/8" stems like the 360 heads, you could put the 1.88"+ 1.60" valves in but it wouldn't help unless you port the bowl beneath the valve. For gaskets first you must maintain .045" minimum between top of piston and flat portion of head. When you remove your existing head the height of the piston in the bore will decide your thickness. If the piston is even with the deck then .045", if it is down you could use a composite .025", measure with a good straight edge and a feeler gauge will do. I strongly recommend the HP Book, How to Hot Rod Small-Block Mopar Engines, by Larry Shepard. If you go to a machine shop to grind in your bigger valves make sure they have done this before on a Mopar head, and you might want the valve guides lowered a tad. Just thought if your changing pistons mind the compression height, distance from pin center to flat portion of piston.

 

[Coronet 500]

Here is something I just remembered, good reading for 318 or 360 budget guys.
http://www.allpar.com/mopar/4bbl.html

 

[mattsmopars]

Am I mistaken by thinking that the 302 casting heads are a 318 head and the 308 casting head is a 360 head? I was thinking they were the same design head just had differnet port sizes for the different engine sizes?
Matt

 

[Coronet 500]

The 302"s have 56-65cc chambers, the 308"s have 68-74.5cc chambers.

 

[tjgp360]

hmmmm.... with the cam i selected should i also change the springs on the 302 heads? how do i know which springs to get? also should the rest of the 360 valve train fit the 318 head

 

[Coronet 500]

Always go with what the cam manufacturer suggests, or equivelant. All standard shaft (non T/A) component interchange. The point about machinists I wanted to make is valve depth is key to non adjustable shaft rockers and if they grind the tips you lose hardness. Had this happen to me buy a "chevy" machinist.