what to do??

[moparmuscle123]

ok, i am in a small predicerment, I am building an engine, it an 1985 318, i bored it .030 over, flat top pistons, where my problem lies is, do i use the stock swirl port heads? or slap some 360 heads on? i am also going to be running a 270,280 cam, im looking for a strong reliable engine, power is good but i want reliability.. i also will be using an edelbrock airgap intake and edelbrock performer 600cfm carb its going into a 78 short box, the tranny backing it is a 727 stage 2 shift kit anda torque converter rated at 2500rpm? what should i do??

[Dodgevanman]

The swirl port heads are actually quite good really. Maybe you could have a bit of port work done on them.

Edelbrock heads would really be the way to go, but expensive.

[moparmuscle123]

yea, im not looking to spend to much money on this engine, but the thing is, i cant port them enough for my 4bbl to flow properly, thats where my problem lies

[Moparfreak1980]

magnum heads are a good set up to if you can find some get a set of 360 magnum heads or you could go with some 340 heads your 340 had a bigger bore then the 360 but shared it stroke with the 318

[moparmuscle123]

ill find out what im doing for sure on monday, i have both the 360 heads and the 318 swirl port, the swirl port is 60cc and the 360 heads are 68cc we are trying to see how much compression im going to have running the 360 heads, we figure about 8.8:1 which i feel will be sufficient with my application because i will gain in port size

[Speed Dragon]

If they are '85 heads they are not swirl port heads, they are just stock 318 wedge hedge heads.

I wouldn't run the 360 heads, you'll lose too much low torque. If you do have swirl ports, use them.

[moparmuscle123]

yea, i thought the swirl port heads were a newer style, but thats what the casting number says, from an internet source, ill find out for sure on monday

[Moparfreak1980]

but i depends on what he's after i'm thinking of building a 318 and putting it in a dodge arrow at some point and i'm hoping for 300hp+ i'm thinking some 360 magnum heads should be quite capable of gettin me quite close with various other work to the engine

[Speed Dragon]

Yeah you can make good hp w/ the 340 or 360 heads, due to the larger intake ports/runners. In smaller cars like Duster or Cudas, or even a shortie pickup that's just used for dragging and playing around on the street, they work fine. But if you have a daily driver truck or use it to work with, the loss of the low end torque due to the larger ports is an issue. The larger ports slow the velocity of the airflow at lower rpms, which cause loss of torque. And you already know about the bigger chamber lowering the compression ratio.

Of course, keep in mind, this is all stuff that I have been told by more knowledgable engine builders than me, I haven't actually tried any of this myself.

[moparmuscle123]

i think i might go ahead with the 360 heads, i wont be needing this truck for much work, maybe haul a golf cart and if possible pull a pontoon boat out of the lake, but usually a 4x4 does that job more sufficient.. its hard to decide but the 360 heads are in better shape i think.. im just trying to build cheap reliability.. nothing too powerful right now.

[knowplay]

Dragon is right. The loss of velocity will kill your torque. If this engine is to be driven daily or much on the street, you will need the torque...otherwise leaving a redlight will be like pushing a brick in mud. Velocity = torque and Volume = horsepower. If you increase volume(larger ports), is the motor strong enough to burn it or will it choke down? 8.8:1? Doesn't sound like it. You want reliability? Then go with the 318 heads as that maintains a close-to-stock combination from a design stand point. More flow does no good if you can't burn it or you have to stay at or above 3500 rpm to use it. Being overly concerned with port size and flow is what we call the "Chevy Mentality." SBC engines have high flow so thus more hp per cubic inch...but nowhere near the torque of a Dodge or Ford. Be more concerned with matching all the parts together so you get the most from what you have. More is not always better. hope this helps.

[moparmuscle123]

so, the smaller ports wont affect me using a 4bbl manifold? the 318 heads would be better?

[Eggman]

Yes they will.My 360 heads had to be cut 0.50 thousandths to boost compression with 2.02 & 1.60 valves.

[moparmuscle123]

well my 360 heads are toast, there is about $900 worth of machine work to be done.. so unless I park the truck now, and use the 360 heads of of that, im stuck using the 318 heads, now i can get 360 heads for $75, or use the 318 swirl port heads that i have, and they are newer than 85, i had a bad source, any ideas on what i should do? looking to spend as little as possible

[Speed Dragon]

Use the swirl port heads, they are a good head. And as long as you don't over carb it the smaller ports won't hurt you w/ a 4bbl at all. Get a Performer intake and a 390-500 cfm carb and it should be very torquey and responsive.

[moparmuscle123]

yea, thing is i already have a carb.. a edelbrock 600.. do you think this will still work alright?

[Speed Dragon]

Yeah should be fine.

[swami2806]

If air flow is a problem with the heads you want, put a blower on it! :D