What makes more power: heads or cam?

[69_Mustang 26]

I'm going to guess that heads will make more power, but what would you all recommend; heads or cam first?

 

I have an idea of what heads I want, as well as cam, just wondering which step I should take first and install for the best power gains.

 

These are the cams: http://www.cjponyparts.com/edelbrock-cam-and-lifter-kit-performer-rpm-flat-tappet-cam-351w/p/EDL7182/ Of course it will get all the supporting parts which gets up to around $800.

 

Here are the heads I'm considering: http://www.cjponyparts.com/product.aspx?p=EDL79259 Not too familiar with heads, so any input is appreciated there. These just seem like the most idea heads for my setup.

 

Input/ advice?

[FrozenMonkey 12]

Cam and heads work together to make power. With just a cam and stock heads you will be starving for air (if its too large) and with aftermarket heads and stock cam you will have too much air. You really won't see too much of a gain without them working in concert. You need to know what your power goals are along with what kind of manners you want your engine to have. Match the heads and cam together to get the largest gain with the smoothest power curve.

 

I don't know a ton about the math of this stuff yet but from what I know, those heads and cam together wouldn't be making large amounts of power. I'd make a guess in the dark of around 350ish HP at the flywheel. Not too huge of a jump over stock considering the cost and time involved, IMO. If you are going to do heads and cam, do it once and do it right for your goals. I know there are some folks on here that have done some sick engine builds and I'm sure they will be able to give you more detailed info and correct anything that I've said wrong.

 

With that said, I'd contact a reputable engine shop, tell them what kind of power you want to make, where you want to make the power, how you want your engine to behave and your budget and they will be able to give you a custom grind cam to work best with a good set of 185+cc alum heads.

[BuckeyeDemon 211]

heads first.

[cobra3073 24]

Strongly agree with FrozenMonkey.

 

In my opinion, it really comes down to the WHOLE package AND your goals. Building a motor (for the most part) is about compromises. It is relatively easy to build a motor that will make MAXIMUM power but most folks don't build a motor just for the "dyno."

 

As to your specific question, I have always been of the opinion that the camshaft is the "brains" of any engine and will drive to a great extent what else can (and should) be done to reach one's performance goals.

 

I will only add that there is "power" and there is "usable power."

 

BT

[RPM 1,190]

Ditto what the others said. Since the cam is relatively cheap compared to the heads, I'd save up and do them together.

 

Bob

[69_Mustang 26]

could I just keep the stock bore but increase the stroke?

 

So rather than getting a 4.030 bore, just stick with the 4.0 bore (with the 4" stroke) and get a displacement of 402. Wouldn't that cause less stress and side load?

 

Just a thought.

 

It would be the following parts:

 

This crank (weighs 6 lbs less than stock and is in most of their stroker kits): http://www.amazon.com/Scat-Crankshafts-9-351-400-6000-2100W-Steel-Crankshaft/dp/B003N2RT3S/ref=lh_ni_t

 

These rods: http://www.summitracing.com/parts/sca-66200a/overview/make/ford

 

And these pistons (stock bore; about .4 lbs lighter per piston too): http://www.summitracing.com/parts/uem-kb261ktd-std/overview/make/ford

 

I'm not sure what else I'd need, but that's definitely the bulk of it.

[rwcstang 201]

why don't you go with edelbrocks top end kit?

[69_Mustang 26]

I did think about that. I guess what i really want is to maximize the power out of my system. Which means it will probably be quite awhile till I get to that point, since I want to do the suspension and wheels sooner, rather than later.

[Boogerschnot 12]

Before you get into the piston purchasing you need to see weather or not your bore is still true. Most folks order pistons after having the block checked that way they know if the cylinders need to be cleaned up, which opens them up a little.. hence: 4inch to a 4.030.. in my rebuild I only had to go to. 020 over because the walls were in good shape. If you want to build this in steps, I would start with the cam and intake.. then heads (because of cost) then build the bottom end. Or start with the bottom end and just build the motor in one shot.

 

But it does no good ordering pistons if you dont know what your block will clean up to.. it may already be at. O30 over thanks to a previous owner.

[69gmachine 15]

The cam you've picked out requires screw in studs, so that means you would also need to either remove the heads and have them machined for screw in studs since they came from the factory with press in studs, or buy aftermarket.

 

If you just wanted to pick up a few extra ponies, the cam is a good place to start as the factory cam was anemic. However, you need to limit lift to .490 or less or you risk pulling out the press in studs. It's a lot of work and you will probably get no more than about 270 HP if you install a cam, intake and 4 bbl (and that's assuming you still have decent compression).

 

Rear end gears will usually give the best performance feel when the budget is limited.

[Boogerschnot 12]

Just realized you already have an RPM intake, why not just go with the RPM cam and then at a later time you can add the heads and make some good power.. Look up the RPM 351cam top end kits, i believe they put out over 350 horses or so..

[69_Mustang 26]

350 to the wheels? Hm... Might have to check that out. I definitely want a more track worthy setup than 100% street functional. I'd like to be competitive.

[FrozenMonkey 12]

More like 350 to the crank under perfect conditions. Those Edelbrock kits are a good deal for someone that doesn't want a ton of power and wants to just buy everything that is proven to work together. If you want honest god fearing power in your car you've gotta get in contact with a reputable engine shop and let them help you put together what you really want out of your engine.

[Endeavour32 10]

If it were me I would stay way from edelbrock heads, they are usually only slightly better than stock. I'd look into Dart, AFR or Brodix then really compare your flow numbers, you want the head the produces the most CFM's with the smallest port. Also don't get hung up on flow numbers at .70 lift. I'd take a head with great mid flow numbers and good max flow compare to great max flow and crappy mid flow. Then you also have to compare intake and exhaust ratio. If you have a great flowing intake port but the exhaust is poor then your not going to make the most possible power.

 

As to your cam you need decide what gears your going to run, exhaust, compression, ect. Building an engine piece by piece is a fools game in my opinion, especially if your running a low compression stock engine. Nothing wrong with buying parts as you can afford them, but do yourself a favor and build it once!

[1969vert 55]

Had cam and j302 heads on a 351w ran 12.0 purchaced afr 205s and changed nothing else ...ran 11.49 .....heads woke mine up....

[sportsroof69 13]

350 to the wheels? Hm... Might have to check that out. I definitely want a more track worthy setup than 100% street functional. I'd like to be competitive.

 

Not even close to 350 at the wheels.

 

 

I still say shooting for a peak dyno number is a poor method to base an engine build on. TW185s are an excellent head for a street built 351W. I had those heads, a Weiand Stealth, an and an XE274H, on a stock 351W bottom end, and made 338 rwhp. Again, I'm not big on building something around a peak HP number, so I'll tell you it ran a 12.3 with around a 3000' DA.

[rwcstang 201]

honestly, start going around to machine shops and talk to them. just remember, Having a 351w gives you alot of breathing room in what you want to do. I have a 392 stroker from ford performance solutions & with the parts Im installing it should be 400-420hp to the crank.

[69_Mustang 26]

Had cam and j302 heads on a 351w ran 12.0 purchaced afr 205s and changed nothing else ...ran 11.49 .....heads woke mine up....

 

Wow. I'd imagine you had other major mods done, too?

 

What does your car weigh? do you know how much power you had before and after the heads?

[RPM 1,190]

Way back when the AFR 185's first came out, one of the magazines tested several of the aluminum heads. On a 351w, heads only change netted 60hp.

 

Bob

[69_Mustang 26]

60 Hp isn't too bad. That alone would be worth it to me.

 

It would take a TON of work and money to get 60 HP out of the M3 I had (and the current one), haha. Not quite the powerhouse these engines are, obviously. lol.

Edited January 4, 2013 by 69_Mustang

[69_Mustang 26]

I guess an easier way would probably say how much power I want, lol. I'd say anywhere from 475-500 WHP. :D

[BuckeyeDemon 211]

I guess an easier way would probably say how much power I want, lol. I'd say anywhere from 475-500 WHP. :D

 

those heads you first linked won't get you there. need lots more dough too.

 

if you were to start from scratch, then i think a general order for parts selection is (and yes they all interact so you have to consider everything together at some point).

 

1. cubic inches. this is first and dictates what type of RPMs you'll need to make the power you want to make. the cylinder volume times RPM basically results in air flow. a smaller cubic inch engine needs to spin to a higher rpm to move the same amount of air as a larger inch engine.

 

2. cylinder heads. you'll need a big enough set of heads to get to support the amount of air for the power you want without becoming an airflow restriction.

 

3. intake/headers. basically you'll need to match this to the cylinder head size

 

4. cam. based on your cubic inches, and cylinder head size and compression, this design will put the optimal valve events at an RPM where you want to work and need to be in order to get the power you want.

 

5. carb. choose this after your cam since cam design can effect signal strength to the carb.

 

doesn't makes sense to me to design an engine around a cam.

[FrozenMonkey 12]

If you are looking at that kind of power you are going about this all wrong. I'll say it again. Find a reputable engine builder and work with him. Find out what its going to cost and save. Or I guess you could just start throwing nitrous at your engine and see how long it lasts. Thats the cheapest way to make power.

[sportsroof69 13]

People who think nitrous is cheap, have never used it.