Finally decided on a cam for teen SB. Should I bother with header?

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cudaracer

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After my first top end rebuild of my 72 e-body 318, where I left bottom end alone, I went in a direction with my comp XE262 cam that would eventually compliment a bottom end rebuild. But things have changed and I probably won't be touching the bottom end for several years at least.

Until then, I could not live with a cam that killed everything that muscle cars stand for, so I ordered a cam that will best fit my low CR, street driving style, stock automatic 904 & converter, shift kit and 3.23 rear. I ordered the comp XE250H. I chose that cam & lifter set because I wanted minimal cost & effort ( Hughes whiplash wanted me to order new springs & tool kit to remove, etc.). It's a done deal. Although hardly a screaming cam, it allows me to maintain my dynamic CR (something previous cam killed), and has a power range right where I play at 800-4800rpm as I have never revved above 3500 in my automatic (previous cam was 1600-5600).

So below is my new setup as I was hoping someone can speculate on my new power numbers, as I also contemplate on the benefit for headers, given my situation.

stock 318 bottom with 84K miles, decent compression, no smoke.
mildly ported/matched 308 cast 360 heads, decked 0.020"
thin 0.028" gasket
current CR now 8.2:1
Weiand 7507 DP intake
Edelbrock 600
Curved spring kit in otherwise stock dizzy
Pro Form roller rockers
comp cam 20-220-3 http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=624&sb=2
Dakota exh manifolds with porting

My guess, I am around 320hp with torque at about 350, but all down low right where I drive my automatic. If I have learned anything, it is that waiting for cams to come to life with my trans and gearing, means I am missing out on low end torque fun.

My final question is about headers. Can't speak toward A body, but E body headers done right means I have to spend over $700, not including the cost of modifying my exhaust system to accommodate them, another $200 or so. So should I bother, based on what you have read? Will I benefit enough to say WOW, or will it be more like, oh yeah, I think I noticed a difference?

Thanks all
 
IMO your hp and torque numbers are overly optimistic. But I could be wrong.
I would stick with the manifolds. The magnums flow well and headers will only give you a 10 to 20 horsepower increase at most at your performance level. As you noted the cost will be around $700 for a nice set of TTI's. The cost per horsepower is high, unless the money is not an issue with you.
 
Actually, I am told I should not even care where my HP is, only torque.

So, is 350 ftlbs really that optimistic? My wheezy 2 barrel setup with lame cam & choked off exhaust was at 280 ftlbs. Hard to believe that 70 more is not attained.
 
I don't think any stock bottom end 318 ever made 320/350 without being sprayed or boosted.
And I know for a fact that 020 off the head of a stock 318 still didn't.

Heck they only had 180-210 brand new with the two barrel and a four barrel isn't going to give you another 100-150.

Just sayin.
 
This is just a IMO comment, but, At a basic look and level I think that 320 maybe a little high but not a way over the top est. the amount of head and manifd porting would play a roll.

Regulardless, the question has not been answered by me. I'll just agree with the above. They will not be worth the time and money since your efforts will not deliver any real noticeable gain via the Butt dyno or anything else you can feel.
As a '73 Cuda owner myself, your header choices are;

Doug's - ....................... 1-5/8
TTI................................ 1-5/8 - 1-3/4
Hooker Super Comp's....... 1-3/4

All other headers are the 1 size fits all style and are not worth spit.
The Dougs would be most in the ball park of where your engine performs.
I would not entertain the thoughts of headers on your engine until a camshaft size of a 220 @'.050 or bigger. And then I'd use the headers by Doug. A good way to finish off is with a header back system / kit by Summit racing or Jegs. They come with and without mufflers at very reasonable cost. They fit my Duster pretty good and require only minor trimming at the tail pipe.
 
I just compared your engine to a 1999 318 Magnum. It had 230 hp and made 300 ft. pounds of torque brand new. Plus the Magnum was a truck engine that was built for torque.
 
TrailBeast said:
I don't think any stock bottom end 318 ever made 320/350 without being sprayed or boosted.
And I know for a fact that 020 off the head of a stock 318 still didn't.

Heck they only had 180-210 brand new with the two barrel and a four barrel isn't going to give you another 100-150.

Just sayin.
Click to expand...

The 318 did come more powerful than you listed and pay attention to the increase head size and noted porting if the head and manifolds. Though he leaves the pipe size out. The slightly increased cam size is also a split duration and adds to the extra effiecient engine breathing. While not big, it doesn't need to be.

Again, I do think it is a bit high of a est., some facts remain uncovered.

Take a look at the broom stick cams used in 300HP engine!

The stock bottom end only lacks a piston tall enough for a decent ratio.
 
TrailBeast said:
I don't think any stock bottom end 318 ever made 320/350 without being sprayed or boosted.
And I know for a fact that 020 off the head of a stock 318 still didn't.

Heck they only had 180-210 brand new with the two barrel and a four barrel isn't going to give you another 100-150.

Just sayin.
Click to expand...

Those numbers were my estimates with my new setup.
Stock 318 was around 170 / 280 hp & torque
 
Coronet 500 said:
Ran your engine on Camquest and it said 308hp@5000, 364tq@3000.
Click to expand...

Yeah, I think I am optimistic with my 320 hp estimate. I ran similar with camquest as well.
Like I stated, I am so pathetic with my low end feel now, I crave torque and that is all I really care about and I think I am realistic with 350, maybe even low.

I think my gains might be slightly aided with my mild 308 cast head work with a good 3 angle job, bowl & mild porting and gasket matching. I did similar with my exhaust manifold and intake manifold as well. Lots of hours with the grinder anyway. It sure looked good going in and a general rule of flow work is that, "if it looks good, it probably flows good"....LOL. I actually believe that. I recall bumping my CFM numbers a bit in camquest & that really moved the needle in hp, hence my optimism anyway.

So to update, I am hearing that headers are simply not worth the hp / $$ I would spend. I am glad too. Love my manifolds, painted with POR cast iron grey and they look factory cast. Love the sleeper look as well.

And, I am expecting that with far greater air flow through my new 4 barrel intake system, much better 360 heads worked over, far more lift in the cam along with more duration, loss of the stove pipe pathetically choked off exhaust manifolds and single exhaust now replaced with better flowing larger manifolds running back to dual X-pipe system running through Thrush Welded mufflers......that gains should be quite substantial and more importantly, when I want them.....right from idle. No more power levels that are far North of my operating range.
 
Take it to Milan dragway, that will give you the most accurate numbers. Next weekend is the all Mopar day there.
 
Who cares about numbers? Drive it. You'll be happy with it because it's a good combination. That was a smart cam choice.
 
Thanks Rusty.

So have not yet swapped cam, but I started to replace my Pypes mufflers with Thrush Welded. Got one side done only, started it up to see if I can hear the difference, and so far I hear the Thrush sounding slightly deeper with less sound clatter sound like Pypes. Moved my ear right behind each one. Drove it and the Pypes sound still comes through loud and clear with tons of droning.

I sure hope that mostly goes away when both are done. The reviews on Thrush ranged mostly from too quiet to nice replacement for Flowmaster. Did not hear much on droning.

To be continued.
 
Just put a lower priced set of head mans and some dynamax mufflers on it bout 300bucks.those other headers are 500 and up.raw steel to polished ceramic.for more tone/ noisy rumble purple hornies sound great
 
There are TWO numbers being quoted, thus the confusion. GROSS hp on a 318 2bbl was 230. Check a 1971 318 2bbl horsepower rating (before they went to net). So yes, the 4bbl, heads (good head choice), and cam with dual exhaust should put you around 310-320 IF it is tuned, timed, and jetted properly. The answer to your question is headers will not benefit your motor at your driving habits, under 3500 rpm's. The manifolds will help you on the low end torque vs the header.
 
RustyRatRod said:
Who cares about numbers? Drive it. You'll be happy with it because it's a good combination. That was a smart cam choice.
Click to expand...

This^^^^^…… Pump that cylinder pressure up. If you decide to do long tube headers eventually, these cams WAKE UP with pipes & head work. It won't run twelves,a damn good balance of torque & gas mileage.
 
318willrun said:
There are TWO numbers being quoted, thus the confusion. GROSS hp on a 318 2bbl was 230. Check a 1971 318 2bbl horsepower rating (before they went to net). So yes, the 4bbl, heads (good head choice), and cam with dual exhaust should put you around 310-320 IF it is tuned, timed, and jetted properly. The answer to your question is headers will not benefit your motor at your driving habits, under 3500 rpm's. The manifolds will help you on the low end torque vs the header.
Click to expand...


This makes a lot of sense to me. Never thought I would appreciate headers nearly enough at my rev range, which is far south of 3500.

Thanks for that.
 
Abodybomber said:
This^^^^^…… Pump that cylinder pressure up. If you decide to do long tube headers eventually, these cams WAKE UP with pipes & head work. It won't run twelves,a damn good balance of torque & gas mileage.
Click to expand...

Fuel economy should go way up.
I would auto shift from 1st through 3rd with auto, spinning to about 3500 to make power. Made no sense, but sounded cool. Now, I can expect lots of thrust with far fewer rpms. I don't care if I don't even get over 20, because I was currently getting closer to 10.
 
I don't understand the "headers only help higher RPM" thing. It's bullshit. Headers wake an engine up through the entire RPM range. Why the heck do you think the factory has gone with tubular manifolds?
 
I agree with RRR. Countless comparisons have been done on dynos comparing manifolds to a gauntlet of different headers and even just the cheapo block hugger shorties make more power and torque than the best eom manifolds!

The only benefit I see in stock manifolds is that they aren't as prone to gasket leaks and that they last forever, while cheap uncoated headers won't last very long in severe conditions.
 
Headers are worth 5-20 percent.

Just duals are worth close to 20%.

Headers come with all sorts of baggage. Duals don't.

Your call on that.

Did you look at all at the "256" cam from Comp?

I thought that was the best bang for buck cam they offered.

No spring change and only 10 less peak HP than the "262" with a MUCH better TQ curve.
 
What are your plans for the car , sounds like you just want to putter around town , never getting over 3500 rpm , why waste the money , just leave it stock and enjoy . Have you ever put the pedal to the floor ?
 
YY1 said:
Headers are worth 5-20 percent.

Just duals are worth close to 20%.

Headers come with all sorts of baggage. Duals don't.

Your call on that.

Did you look at all at the "256" cam from Comp?

I thought that was the best bang for buck cam they offered.

No spring change and only 10 less peak HP than the "262" with a MUCH better TQ curve.
Click to expand...

Yup, looked closely in fact, but the slight lift and Dur gains are offset by something I needed to maintain more importantly.....dynamic CR. The 256 intake valve closes 3 deg later after BDC, and thus I give up a lot of DCR.

Thanks though.
 
jerry6 said:
What are your plans for the car , sounds like you just want to putter around town , never getting over 3500 rpm , why waste the money , just leave it stock and enjoy . Have you ever put the pedal to the floor ?
Click to expand...

Well, 3500 rpm with my 3.23 gearing is like 105mph.
I would then ask, why go any faster. In fact, where can you go any faster on the street.

So yeah, it's far more important for me to get to 105 and having a huge grin on my face, than taking it any faster in a car that does not feel safe to do so in the first place.
 
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