318: too much cylinder head?

[1wild&crazyguy]

the bigger valves and port work will do nothing........but make the 318 run better from top to bottom. I believe it would be difficult to get the ports too big in the edelbrock head for the way your 318 is built, and that the head is probably too small for a really good running 408 stroker. But what the heck do i know?

op, listen to this guy.

 

[benmopar318]

I'm in pretty good with a machinist/builder who does top work and I trust him 100%.

He actually builds 5L ford and chev engines to the tune of about 650hp for a couple of teams in our nation's flagship motorsport, the V8 Supercars. but most importantly he has a passion and knowledge for mopars.[/QUOTE]

That would have to be Jason Maros aka Moparos

in my case having a decent convertor built is the key to happiness, it will cruise at anywhere from 1600-2500 in top gear with 3.23s and lock up enough to accelerate with out flashing but stab the throttle and it flashes to spot on 4000. i'm finding once i see 5-7K it really hauls *** so should be great when the 4.11's go in. After testing this out with the old Edelbrock carb i have a new Quick Fuel 750 annular to play with and tune.
I will some fun with this std motor which has 645 rods and has been great over the years the next bottom end to go in is another 318 .030 bore with 273 699 rods and KB399 pistons, .557 purple shaft solid with a Super Victor intake on top.

 

[273]

is that cam the XE262H-10?

if so, I would consider that extremely mild for an engine with Airwolf heads and perhaps not such a great match.

Which dyno program do you use?

I use engine analyzer Pro.

I use Dynosims pro 5, XE262H-10 is the cam I used I was just playing around since the air wolfs make 300cfm at .500 lift I wanted to see what numbers a mild cam with .500 lift (xe262h + 1.6 rockers) would do if the real engine came out anything like that dyno curve it had useable power from idle to 7000 and would idle like a stocker.

 

[rumblefish360]

Flow is not how you should pick a cylinder head. You need to know what you want from the engine, and then get the head csa where it should be. If you have a 2 heads, one flows 280 cfm at .500 and the other flows 300cfm at .500, Most times the higher flowing head will have a larger port/valve. If that's what the engine wants (HP, RPM) then it will make great power. If not, it will be a bag of $hit!
Brian

I agree. While it would be great to get 300 cfm of air through a head at .500 lift, it would be awesome if it were through a stock size (Ported) head. A big valve in my experience really doesnt do great things in the lower RPM and speed of the car. AKA, driving down the slow roads.

To much porting/ over sized valves on a street motor will cause a lag in the bottom. The heads I have are hogged out, with larger valves (cast iron). A friend that has been racing Mopars his whole life said they as good as very worked X-heads, I was going to put them on a 273 , he said no. Yes , I am off topic. However, if you have the right cam, gears, ect, a properly built mill, will pull hard, throughout the power band/ RPM range.

It's all in the combo. Considering the post starters first post and combo....
I have found a big valve can suck on the street in the wrong combo.

You should check out Dr DJ's air wolfs they flow 300 cfm @ .500 but there 220cc ports.

Seems to be a lot of port @ 220cc for a small engine.

The bigger valves and port work will do nothing........but make the 318 run better from top to bottom. I believe it would be difficult to get the ports too big in the Edelbrock head for the way your 318 is built, and that the head is probably too small for a really good running 408 stroker. But what the heck do I know?

In his current build state, I say probably. (An agreeing statement, to a degree, but) I do think the other side of this is the gear ratio and tire size he has chosen. I do not see it so well with the engine set up. While a bigger port may be good for this build, (IDK, haven't been there myself with a 318) I'm making a error (?) on the side of caution for this in favor of a recommendation of a port to large.

You make me LOL with this

But what the heck do I know?

So I want to know, have you done a 318 like above and if so, do you have anything for our viewing pleasure?
(Not challenging, just hoping so for more knowledge)

rumblefish, I know this is off topic. but are you having the same issue I'm having with the cursor disappearing out of the message box while you're trying to type?

RPM and engine displacement are relevant to each other directly.

Like it or not HP=TORQUE X RPM / 5252

therefore mathematically, all things being otherwise equal a 100ci motor would have to rev 2x as many RPM as a 200cu motor to pull the same air through the heads/carbs to make equal horsepower (at a much lower torque level)

Engines in their most basic form are an air pump. you have displace 20% less air per revolution you have a choice of performing 20% more revolutions in the same time period. or making 20% less horsepower.


re: driveline

Perhaps I could gain a tenth or two from changing my gearing and tires however it would completely remove the car's sleeper appeal.

I fail to see how increasing the average port flow in all used lift ranges by circa 30% could NOT cause a gain in net useable RPM and HP especially with a 114LSA cam.

I was on my i-phone, it worked fine. I'm home today (FREAKIN YEA!!!!) no problem. I get the wife to fix such things. I take care of 90% of everything else. ;)

Frosty, I think your reading this to black and white and not as a whole picture and on top of it, while you told me like it or not, well, again, I think that while formulas are great and experienced been there done that builds from our builders and members are tops, even more so when they have done near exact combos, I have found these formulas to not always work or work as intended.

While some things work out on paper, in reality, they can fail to do so in the real world working environment. And will do so.

It remind's me of a time when I was arguing that all HP and Tq. points do not always cross at 5252 or what ever the number was. 10 people said I was wrong and dumb. It took some time to prove them wrong, but by then.............

The 114 thing.....112 is pretty good as well. Crane cams does this a lot. Though the theory is sound in your head, the cam might not be cut in that manor. Check with the grinder before you purchase. Just let them know your looking for a super smooth idle.

Also, I forgot, the 1.6 rocker is a great idea in my mind. Though the head should be able to handle the lift. It is rare, but sometimes a lift rate to great happens.

All in all, I look forward to this and it's completion and testing and/or in car haulin ***.

 

[frosty_the_punk]

Listen Punk...can I call you Punk?? Ha ha...anyways, mr. frosty (I like snowman better but that's just me) here is the major problem...street/strip!
Anytime you need to have an engine pull double duty you compromise alot...and the smaller the engine the larger the compromise!!

The sixpack setup is very restrictive in OOTB form. So beware!

The heads will not be the cork in this combo, it'll be the small engine + need for street drivability + 6pack setup.
Cam I would choose would be closer to 232@ .050 intake, 242@ .050 exhaust, on a 110 lca and advance it 6°. Don't worry about idle, as you can tune the carbs to work with less than 12".
Now if you were to go with an 8" converter you can run a larger cam.

You may call me whatever you like, Most call me Frosty and some even call me ian.

What is the advantage of a smaller diameter on the converter?

The converter I have stalls at 3500. the gears I have are 3.7 with a 25" tire.

in terms of ratio they are equivalent to a 27" tire with 4.11 gears.

I understand the surface contact patch is smaller with a 25" tire to a 27" but is there something more that I'm not seeing?

Every time I mention my ratios everyone insists I change it, but I'm really happy with it, the gears and stall seem to really work well together as far as I can tell.

If you were picking a cam and an 8" converter for a 318 with these heads. how would you spec the cam and stall?

can you give any specific critique on my proposed cam grind?

Also is there any advice you can give on optimizing the six pack manifold for less restriction?

 

[Brian Hafliger]

You may call me whatever you like, Most call me Frosty and some even call me ian.

What is the advantage of a smaller diameter on the converter?

The converter I have stalls at 3500. the gears I have are 3.7 with a 25" tire.

in terms of ratio they are equivalent to a 27" tire with 4.11 gears.

I understand the surface contact patch is smaller with a 25" tire to a 27" but is there something more that I'm not seeing?

Every time I mention my ratios everyone insists I change it, but I'm really happy with it, the gears and stall seem to really work well together as far as I can tell.

If you were picking a cam and an 8" converter for a 318 with these heads. how would you spec the cam and stall?

can you give any specific critique on my proposed cam grind?

Also is there any advice you can give on optimizing the six pack manifold for less restriction?

The 6pack setup needs porting! Alot!!
114 is way too wide for a small engine like this. It will be lazy...very lazy.
The smaller you go on converter, the more stall and rubber band effect you get, but this also heats the trans fluid excessively because while cruising your "slipping" the converter like a clutch and creating heat...like I said, street/strip engines are the toughest to build.

Taller tires have more sidewall give and this can help with traction. Ha ha, my oldest sons name is Ian!!
Did you see my cam recommendation?

 

[rumblefish360]

Ian the Frosty one.

On the tire and gear combo, the larger tire is better for hooking up and taking off in the car. Also considering the amount of power you'll be making, it'll look like your barfing torque out all over the place spinning tires. Instead of hooking and booking.

A small diameter converter will get the fluid out faster, weigh less and allow the engine to spin up quicker due to less rotating mass.

 

[moper]

...like I said, street/strip engines are the toughest to build.

Agreed 100%.

Some other thoughts
- The last small block engine I had dyno'd with a 6bbl and an Air Gap and HP950 showed a 46hp diffference. The pwner wanted the 6bbl, I wanted the Air Gap. The 6bbl took a 540hp engine down to 496.
- With the cam - I really think the heads need to be done first, then once you have those results in hand, re-visit the intended power needed and other qualities you want the engine to have, and then a better choice be made. Dyno sims are fun toys but the further you get from a mild package, the less accurate they are.

 

[frosty_the_punk]

Agreed 100%.

Some other thoughts
- The last small block engine I had dyno'd with a 6bbl and an Air Gap and HP950 showed a 46hp diffference. The pwner wanted the 6bbl, I wanted the Air Gap. The 6bbl took a 540hp engine down to 496.
- With the cam - I really think the heads need to be done first, then once you have those results in hand, re-visit the intended power needed and other qualities you want the engine to have, and then a better choice be made. Dyno sims are fun toys but the further you get from a mild package, the less accurate they are.

Was that with or without the promax jet plates and metering blocks om the 6bbl?

Often people like to compare ootb six pack to a fully tuned and jetted 4bbl and wonder why they don't perform comparably.

 

[moper]

The engine is a pump unleaded 416, with stage 3 RPMs from Shady Dell and a small street solid roller. The 6bbl was port matched, and the carbs were brand new with the Pro Max jet plates and billse base plates. Both inductions were tuned and the figures are the peaks for both. It's been driven weekly in CA since I built it - I think it was 2006.

 

[frosty_the_punk]

The engine is a pump unleaded 416, with stage 3 RPMs from Shady Dell and a small street solid roller. The 6bbl was port matched, and the carbs were brand new with the Pro Max jet plates and billse base plates. Both inductions were tuned and the figures are the peaks for both. It's been driven weekly in CA since I built it - I think it was 2006.

That's weird I've seen mag articles that put the six pack in the thick of most top performing manifolds.
guess I'll have some manifold porting to do! :burnout:

 

[451Cuda]

Air speed is much more important than max flow. Go with the smallest port you can that produces decent numbers.

 

[crackedback]

Agreed 100%.

Some other thoughts
- The last small block engine I had dyno'd with a 6bbl and an Air Gap and HP950 showed a 46hp diffference. The pwner wanted the 6bbl, I wanted the Air Gap. The 6bbl took a 540hp engine down to 496.
-

That sounds a bit like Bob's engine in a Challenger.

 

[1wild&crazyguy]

Air speed is much more important than max flow. Go with the smallest port you can that produces decent numbers.

While this can be true to an extent...the heads that are being mentioned are all on the small side to start with.

 

[moper]

That sounds a bit like Bob's engine in a Challenger.

Bob R?

 

[451Cuda]

While this can be true to an extent...the heads that are being mentioned are all on the small side to start with.

Mainly referring to this 318 and the heads mentioned so far, but yeah there definitely are times you want a huge port.

 

[crackedback]

Bob R?

Not to hijack, yes that one.

If it is, his engine is one of the best indicators of a 6 packs issues. Put a decent 830-850 cfm 4 barrel carb on a Victor340 or Air Gap and it gets it's butt handed to it.

Those mag tests are not comparable cfm across the board.

 

[frosty_the_punk]

Thanks guys, I think I'm going to go ahead with the porting on the Edelbrocks.

Once they're ported and flowed I think I'm gonna talk to my cam company over here in aus about a 242/242 110LSA +6 solid grind.

It should be quite similar to lunati's factory performance cam 404A1LUN

I'm also going to start reading up on do's-and-dont's of intake manifold porting

 

[rumblefish360]

Agreed 100%.

Some other thoughts
- The last small block engine I had dyno'd with a 6bbl and an Air Gap and HP950 showed a 46hp diffference. The pwner wanted the 6bbl, I wanted the Air Gap. The 6bbl took a 540hp engine down to 496.
- With the cam - I really think the heads need to be done first, then once you have those results in hand, re-visit the intended power needed and other qualities you want the engine to have, and then a better choice be made. Dyno sims are fun toys but the further you get from a mild package, the less accurate they are.

X's 2!!!!!!

 

[rumblefish360]

I'm also going to start reading up on do's-and-dont's of intake manifold porting

Where is the info from? Gotta link?

On the 6 pack, the runners are all a mess in that some are short runs into the head and others are long drops from the carb and then bend hard. I'd love to see a revamp of that intake done in a RPM style, raised runners and intake height.

While the intake can perform, a lot will have to do with the cam and the RPM band. IDK the limits of this intake. Like said above, a Victor and a 830 cfm would out perform it in many combo's, though the driveabilty may suffer with one big carb.

It can be come the age old problem, everything was done in the "Bigger is better" fashion and now it suffers from it.

 

[Cudafever]

Thanks guys, I think I'm going to go ahead with the porting on the Edelbrocks.

I thing you need to re read this and ask the "right question"!

Flow is not how you should pick a cylinder head. You need to know what you want from the engine, and then get the head csa where it should be. If you have 2 heads, one flows 280 cfm at .500 and the other flows 300cfm at .500, Most times the higher flowing head will have a larger port/valve. If that's what the engine wants (HP, RPM) then it will make great power. If not, it will be a bag of $hit!
Brian

Getting the right port CSA(Cross Sectional Area) or MCSA (minimal) will make all the difference. if you have it ported larger then what is need. you will make less HP in your choose rpm range, then if you left them stock.

 

[frosty_the_punk]

I'll keep them in the 190-195cc range on the intake side.

That still leaves heaps of room for improvement over OOTB heads.

 

[moper]

If you're open to it, the Indy Mod Man with the 6bbl top may be a better option. It will still be a dog low down on a 322, but it will make the numbers up top.

 

[1wild&crazyguy]

I'll keep them in the 190-195cc range on the intake side.

That still leaves heaps of room for improvement over OOTB heads.

dont even need to go that big.imo

 

[frosty_the_punk]

I'm considering a 390 now.

My engine builder says he doubts the chambers can be taken out on the Ede heads to accommodate the dome top pistons.

looks like if i do the 390 I'm gonna end up with enough left over pieces to build an entire "hot" 318. lol ops: