318 and which cam?

-
solracmopar

solracmopar

Well-Known Member
Joined
Mar 24, 2010
Messages
192
Reaction score
5
Location
Orlando Florida
I'm trying to get some more thump out of my 318. I'm currently running stock bottom end/heads with a edelbrock intake/600cfm carb and a set of Dougs and a 420 cam.

The options I'm looking at are a 454 or possibly a 480 and changing springs in the heads.

Curious if anyone can chime in on some suggestions. I'm on a budget but know someone else out there in my situation has probably gotten some good results?

Thanks in advance
 
I'd second the xe262, there a build with bascilly your engine with that cam making 282hp
 
So basically to keep my life simple go with the xe262. Any ideas on lifters? Would I need to tweak the stock heads or stall any?

Really appreciate your input guys.
 
You can use stock stall and head work not needed but porting and more CR = power, 318 heads are good for about 325hp stock but you need larger cam but to use larger cam you need more CR, stall and gear. So unless you want your build to snowball just slap in a XE262 or similar from another company.
 
Thanks 273. I know its a dumb question but what is CR? I'm now considering having the heads ported and maybe beefier springs? Ordering my XE262 from Summit tomorrow..
 
solracmopar said:
Thanks 273. I know its a dumb question but what is CR? I'm now considering having the heads ported and maybe beefier springs? Ordering my XE262 from Summit tomorrow..
Click to expand...

CR = compression ratio. When you order the cam order the appropriate springs at the same time.
 
Thanks Badsport! So conclusion is XE262/lifters + port heads + matching springs and leave the rest of my set up the same. When I talk to the machine shop tomorrow are there any specifics re: porting or should they know re: 318 heads?
 
Could shave the heads for some cheap compression. Then you would need to shim rocker shafts. Just an idea. I did this with a low compression 340. Shaved the heads and ran thin head gaskets to get 9.5:1 out of it with a Lunati .480 cam, LD340, holley 750. Huge improvement over stock. i bet all together was a good 50HP gain
 
Right on singer340. Your now the second person that's told me to do that. Thus far here's my plans for the machine shop:

Port match the intake and exhaust gaskets, and do some nice cleanup on the valve bowls, opening them up a little where the valve seat merges with the bowl.

Also considering going to stock 360 intake valve size, 1.88 diameter, and put new intake valves in (from a stock 360).

Then, a 3 angle valve job at least on the intake seats, or on all of them.

For the springs I'm thinking stock replacement 340 valve springs.

Hoping to get a solid 50-75 hp extra out of the engine.

Can anyone tell me how to easily post pics on threads like this? I'd like to add some shots even if their redundant. Thanks!
 
I am doing heads for my 318 now - I'm swapping on 273 heads from the original engine. Those or the "302" casting 318 heads would probably be good for you. Instead of ~half a compression point, with milling you could bump it 1 or more points I think.

Honestly, I think the most you can do for these engines lies in the cam and heads, based on flow and compression. It might cost you another couple hundred bucks to change heads, but IMO it's a really good bang for the buck. You'll sink all that money into your current heads and probably not even hit 9.0:1 compression with stock pistons..you can do what I did, and re-use your valves, etc from the current heads, I just went with Comp 901 springs, everything else stock (XE268 cam).
 
Funny enough I just came across a set of the 302 - swirl port heads. Guy says they need work but everything is there. Now I'm considering these for $150. Could be a whole lot cheaper and better performance than dealing with my 318 heads.

The same guy has a set of 340 J-heads (1.88 intake) for not much more $$. Anyone know which would be the better of the two to look into?
 
The 302's have a very small combustion chamber and will up the compression a bit.
"J" heads are open chamber and may lower your compression. I'm running a 318 factory roller cam and ''302'' heads in my old truck and was very suprised how good it runs. Actually runs better than when the 360 was in it.
 
Heres a shot of the 302's
 

Attachments

  • Copy of 88truck_1.jpg
    92 KB · Views: 467
I second the 302 choice over the j heads. You'll gain compression and have more than enough flow for the smaller cam you're using.
 
I just got back from looking at these 302 heads. Turns out they are Magnum 302's. Didn't know there was a difference. Does anyone know what year car/truck the 302's came on? I'm about to start hitting the junk yards.
 
Darter6 said:
The 302's have a very small combustion chamber and will up the compression a bit.
"J" heads are open chamber and may lower your compression. I'm running a 318 factory roller cam and ''302'' heads in my old truck and was very suprised how good it runs. Actually runs better than when the 360 was in it.
Click to expand...

Are you running stock 302 heads or have they been ported, bigger valves etc?
 
Yes, mine were stock, just a cleanup.replace 1 valve, redo the valves and seats. The engine was from a 85 Dodge Diplomat
 
Looks good! I love the look of a fresh set of heads for some reason, lol. Did you end up getting them from the online place or no?

I'm picking up mine from the shop today, really antsy to put them to use!
 
solracmopar said:
Heads picked up today.. :blob:
Click to expand...
so, are these the stock valve springs for those heads, did you settle on a cam, does everything else bolt right on to these and any guess how much this should raise to CR ?

thanks
 
You must log in or register to reply here.
-

Back
Top