There's been a lot of 318 talk recently, so I thought what better way to have a little fun than have a hypothetical 318 built thread? Just a couple of rules. Must be stock 3.31" 318 stroke and "whatever" bore. Whatever heads, cam and pistons is fine, but no stroker. You start talkin stroker this and that or "use a 340 or 360" go start your own thread. Also, this thread is for naturally aspirated builds. No power adders like blowers, turbos and nitrous. Go start your own thread. This is to help guys with 318 builds get a good idea of what they are capable of. So with that in mind, here is my recipe for "around" 300-325HP 318 build.
I would start with a 5.2 Magnum engine since the LA platform is so old now, decent cores are getting pretty tough to find. Also, we have the advantage of a factory hydraulic setup and 1.6 rockers. With that in mind,
9.5:1 blueprinted compression ratio. Stock Magnum 1.920/1.625 360 (Thanks
@66fs) valves in the Magnum heads with bowls blended nicely. If you can afford to port the rest of the way, or do it yourself, knock it out, but it's not necessary. A good quality multi angle valve job is a must.
For camshaft, I'm ASSUMING since you want a hot 318 that you're gonna want to rev it some and play around so I'm choosing a pretty stout grind. Grind #1408 on the Oregon Cam hydraulic roller list. .480 lift both sides, 224@ .050" intake and 230@ .050" exhaust, but we're gonna get them to grind it on a 106. They will do that no charge. We will use stock Magnum lifters. They last a long time, so if you find a good used set, more power to you. We'll utilize the Hughes Engines 1110 valve spring.
On rocker arms, I like adjustability and IMO, the most cost effective is the kit Hughes Engines sells.
ROCKER ARM KIT
Might be cheaper ways, but this gives you everything you need in one fell swoop and it's pretty nice.
As for intake mannyfold, I like the air gap style. The port match to the heads is important, so you'll need to include having the heads and intake port matched in the budget. Well worth the money. If you want to go further, and can do it yourself or afford it, great, but all I'm calling "necessary" with this build is the port matching. With that in mind, get the genuine Edelbrock if you want, or the chinkese knock off, it really doesn't matter.
Just like with the camshaft, I'm assuming you're gonna run this little beeotch, so I'm gonna choose a Quick Fuel Brawler 650 dual line double pumper.
On the ignition, all yall know I like the stock Mopar style electronic ignition. I recommend sending the distributor to
@halifaxhops Ray and he will hook you up with a good hot ignition curve. He can even fix you up with a good, NOS quality ignition ECU box, or the other I recommend is the "HI Rev 7500" available at Jegs. I got mine off Amazon and it came in a Jegs box.
As for exhaust, again, we're not buildin a pussy 318, so this gets headers. I recommend the biggest primary tube header you can afford and also a complete 3" exhaust to the rear bumper with constant diameter mufflers "of some kind".
This should actually about cover it. You WILL have an honest 300-325HP and possibly more depending on how far you want to go with port work.
So that's my recipe for a good hot, reliable 318. What's yours?