Add hotter cam or Add hotter head ?
- Thread starter 318willrun
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I'd pick heads. That is where the real power comes in. The better cam combo you have the more you can take advantage the potential in the heads. Not saying it is the most cost effective but it gives a better base to work with. I've run "J" heads on a 273 with a 340 cam, and was surprised at the power level compared to stock heads and a 284 duration cam. Not even in the same league. At some point you run out of potential or driveability with a cam.
And wear.
You do realize replacing only the head could actually hurt performance without a cam or intake change.
intake mentioned in the original post was a eddy performer with a 600 on top. And I think you can kill the engine with a cam swap very quickly without a converter and gear change. Have to be super careful with the cam swap....
I have never seen that. But I don't mess around. If I need to mill for compression, that is what I do. In reality, high performance requires a cam and better valve springs. But if I had to choose between a cam and better heads, I would pick heads. The engine does not care how it gets the air, just that it gets it. If the heads can flow enough air at a certain lift, it does not matter. We spent a lot of time searching and finding the best head castings, Mopar, Ford, and Chevy before we started on the rest of the engine.
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I’m not understanding
Example: Hughes Whiplash cam, designed for low compression engines
Bingo
IQ52 has demonstrated a couple of low compression builds that make good power. Being low compression, 87 octane is a shoe in. Sure there not setting the house of fire but it does show a low compression engine with decent flowing heads and a small cam can make an engine a lot happier and be cost effective as well as easy enough that a rookie can pull it off.
IQ52 has demonstrated a couple of low compression builds that make good power. Being low compression, 87 octane is a shoe in. Sure there not setting the house of fire but it does show a low compression engine with decent flowing heads and a small cam can make an engine a lot happier and be cost effective as well as easy enough that a rookie can pull it off.
MOPAROFFICIAL
Oogliboogli
Heads that flow 10-20+ cfm more in the .1-.400 will show more power increase/lower et with the existing running gear/convertor.
More flow...manners stay the same...power just goes up.
Not talking about the wrong head..."too big" but the right head.
Did this. Heads alone can bring it up a ton.
Can you also have stock ish ca timing and higher lift , sure..but the way they flow..its not much gained without changing the cam timing events and lengthening them .which changes the manners and 98% of the time requires more gear or convertor.
More flow...manners stay the same...power just goes up.
Not talking about the wrong head..."too big" but the right head.
Did this. Heads alone can bring it up a ton.
Can you also have stock ish ca timing and higher lift , sure..but the way they flow..its not much gained without changing the cam timing events and lengthening them .which changes the manners and 98% of the time requires more gear or convertor.
Cam
Like the 340 cam:
430/444 lift
268/276 duration
Will work good with stock heads and the 600 on top.
Like the 340 cam:
430/444 lift
268/276 duration
Will work good with stock heads and the 600 on top.
And it's interesting to hear the comments about the 340 cam in a Teen. Some say you need a convertor and some say you don't. A higher stall convertor should help especially if you are having issues getting it to idle slow enough for gear changes from park to reverse and drive.
As you know, a good convertor always helps. I've run the 340 cam in a 318 with a stock convertor. The cam still helped for sure, but maybe not felt from 0-30 mph.
This cam with a factory head will outperform a stock short block with a higher flowing head.
60', 1/8 and 1/4 mile and your favorite dyno too. lol
I call bullshit on anyone testing a head change only on a stock cammed short block.
Dale Davies
Well-Known Member
Depends on what cam is in it now and what future plans may be in the stew pot. With stock heads the cam choices are restricted some. I would think go with a cam, even if the heads are the choke point. Then later the heads can be dealt with. Uncle Tony is doing up an engine using mostly stock parts. Yes, an aftermarket cam. Valves are being replaced in factory casting heads. Porting with DV and Unity Motorsports involvement. They are using the Carter 2 barrel carb also, so the build is a bit like a restrictor plate engine. Aluminium heads not allowed. Will be interesting to see the results as head work vids come out and the final dyno result.
MOPAROFFICIAL
Oogliboogli
I take it you've never done it.
You'll have to explain how it won't make power when it flows better at every lift with the same cam. For some reason.. I think even the tv crap shows have done it.
I have a truck with 311k on the stock short block that after tossing on some purpose ported heads feels like twice the engine it was.. and now rpms higher=hp why? It now has available 10-40cfm per .100 lift.. As for stock cam range/rpm...the valve springs are one of the main hindering factors of squeezing all RPM you can..and after running 50 years.....they're toast.
Stock teen runs 85 seat and 180 open, maybe . You need at least 250lbs open load to turn 5500 with .450 lift and not encounter spring spin/bounce boogaloo.
If the head can fill that same cylinder more per .100 lift and the Springs are upgraded to allow it to spin up and use the entire range of that cam 'which is a little bit more than it says' .....power increase.
MOPAROFFICIAL
Oogliboogli
Look at the flow increases .100-.400 on ported 318 heads, low 130's cc intake port small fast exh, then ponder milling them from 'open 68 .022 to 64cc' or 'closed style 66cc milled .024 down to 62cc'...
I think when people read my initial answers they don't figure in that you have the ability to have a smaller combustion chamber and that means more compression and yes that means a few more horsepower as well.
The 318 heads I've tested near .400 lift are only around 160 something CFM... ported with the same valve they're at 195-200 CFM with gains also below. It's obvious if you factor everything...you're looking at an available airflow increase to make 70 more horsepower. 'At the heads' ...and all inside the stock cam lift range. Ps, no one said you can't run a geometry kit .lol
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I'm not doubting an increase from a head alone.
I'm saying the right cam selection will produce more power up to a point over just a head change on a stock cammed block.
To the OP, only a chevy guy changes a cylinder head before putting on headers. lol
Looks we need to get out the dyno!
I think the exhaust manifold will be the choke point . lol
Depending on what other mods are done. My old 73 Challenger with a stock 340 didn't get any faster with just headers. Pretty disappointing to say the least.
Here's a 4bbl xe262h cam and headers on a stock 318 long block makes 282hp @ 5000 rpm
How much more hp could you squeeze out of the 318 heads with what cam do you think?
I'd say at least 300 hp but probably somewhere between 300-325 hp without adding more cr.
318 Long Block Bolt Ons - Tech Articles - Mopar Muscle Magazine
MOPAROFFICIAL
Oogliboogli
Nah won't need a dyno ..because the question was which one would move it down the quarter mile faster, cam or better head "in its existing form w/ exh manifolds"
Cam it and access the tiny 175 cfm but still be limited by the gear n convertor ..
or
have near 200 cfm peak intake by the stock max lift...stretch the power band with the better flowing exh port and support it with more spring...meanwhile also raising the compression..umph in the low end/part throttle...more a/f =power.
Cam it and access the tiny 175 cfm but still be limited by the gear n convertor ..
or
have near 200 cfm peak intake by the stock max lift...stretch the power band with the better flowing exh port and support it with more spring...meanwhile also raising the compression..umph in the low end/part throttle...more a/f =power.
MOPAROFFICIAL
Oogliboogli
How many 400 horse 360s out there that run like **** down grandpappys pant leg after the sunday chili potluck .
Quite a few. You could take a motor that makes 300 400 whatever horsepower and stick it in a car with the wrong gears and converter ,manifold and the rest.. and have as much go from a dead stop than a well tuned 64'-65' 225 valiant
Quite a few. You could take a motor that makes 300 400 whatever horsepower and stick it in a car with the wrong gears and converter ,manifold and the rest.. and have as much go from a dead stop than a well tuned 64'-65' 225 valiant
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