Dart 347 stroker, needing some help.

So its been a little while since ive been on. I have got a Dart SHP block which im super excited to hopefully get built in the next year, In the mean time... (im not brilliant by any means when it comes to building a motor) Im building this car to hopefully make it into the 10's, I have a complete forged rotating assembly with I beam connecting rods (347 stroker) I have a ford racing F303 cam as well as Ford racing lifters, an edelbrock airgap intake manifold with a holly 750 double pumper carb., complete msd ignition system. I have a set of edelbrock e street heads which at first the car was only going to be a hipo street car needless to say i know I need a new set of heads, this is a roller motor which with what i have read the roller motors seem the have valve float issues with the afr 185 heads unless changing the valve springs and increasing seat pressure... pretty much I need to know a good set of head i should use, id be happy to run a 10.99 in a 1/4. I have specs on every single part ive bought so if any of that helps i can get it.... also ill be running a 4 speed top loader trans. thanks in advanced

 

forged is good because you'll need to rpm the motor a bit more to reach into the 10's. move up to the 205 head and ditch the dual plane for a single plane with spacer. run a cam in the 250* range(@.050) and keep the compression up too

I surely know how your excitement level must be since I just got an 8.2 inch aluminum BMP block to build on. Can't hardly wait to polish it/debur it and finish the machining

 

victor jr and I agree go with 205 with small cambers to boost comp higher. ate you stuck on that cam?

 

Before you ditch those E-Streets, I would contact Ron Robart at Fox Lake Racing. He has a CNC program that can substantially improve the flow of these heads. You can check out the entire process on YouTube by entering Fox Lake Racing in the search function. It will take you through the process.

Ron has done work for me and is meticulous.

Fox Lake Power Products
6060 Dalton Fox Lake Rd, North Lawrence, OH 44666
(330) 682-8800

 

Im not really stuck on the cam, I bought the cam the same time i bought the estreet heads, im saving the heads for another 302 motor that I want to either put in a fox body or a ranger. This car is going to be ran on the street.... barely thats why i had the dual plane but i can go away from that as well.

 

http://www.airflowresearch.com/index.php?cPath=21_104

something like these? I have forged pistons with valve reliefs would they still need notching?

And would the raised exhaust port location affect my full tube headers? Im going to be running the original non power steering set up.

 

Also rocker arm? 1.6 or 1.7? Ill probably go with comp cams gold series, this is going to be a naturally aspirated engine. I have a friend with a falcon with a 351 running in the 9s naturally aspirated not tubed on stock suspension, pretty awesome car. And when you say use the victor jr with a space you mean carb spacer? If so how much of one i know they have 1 and 3in.

 

ok.. I have some time.. so here you go.

Yeah.. AFR 205's.. or comparable.. would be the bare minimum you'd want on that motor. As you read and study about port designs and any specific heads absolute power/modification potential(hardcore engine forums), you'll find that it has much to do with MCSA restrictions around the short side radius which causes smaller ports to quickly fall off at higher lifts. You could even step up into a 215 cc port design if you decide to RPM that thing past 7,000 more than once in a while(better have good quality rods and/or ultralight piston/ring package). Heck.. many would even argue the merits of a 225 head on your combo but it doesn't sound like you're spending towards 600 horses here.

Typical valve reliefs should be plenty deep unless you want a really long .700+ lift cam in the thing but pays to triple check while spec'ing parts. I'd shoot for around .640-.660 lift for a good port and spin it up to about 6,800 - 6,900 rpm. 460HP.. easy beans. Maybe even close in on 500 if you wanna work hard for the last of it with merges/collector lengths. intake spacers and all the extra tuning time.

I think by reading most other responses to header fitment will show you that 1/8" isn't so tough to massage parts around.. but it's the 3/8" and higher stuff that really makes custom header guys happy all the way to the bank. BUT.. the one constant that you need to be well aware of with header fitment on ANY raised port head is that even a puny 1/8" deviation is easily magnified down by the collector as it simultaneously moves upwards AND outwards due to the heads flange angles. Sometimes it's just cumulative and even aftermarket heads with "stock port locations" can cause some basic engine width variance as well.

And rotor certainly has a valid point in his above response because mine(pre-e-streets but still 170cc port size) are hand ported to the max.. to the point of carbide almost pushing into water/pushrod tubes/offset rockers and the whole ball of wax and they do well more than all right for an entry level head. On the other side of the coin is that they're simply too small even in ported form. So, while TEA's work is pretty nice($$$).. you simply can't turn a street casting into a race casting. Street/strip.. is about as far as they'll go with heavy work(CNC or otherwise) because there's just not enough material poured in to work with. Especially the short side and its transition to the outer wall which results in trying to stay out of water and its MCSA always ending up too small. Which then of course results in the SSR ALWAYS being too fast. Then.. turbulence/sudden stall and/or max flow loss is like a kick in an intake ports nuts on a fast moving motor. Basically causes the motor to feel like it's laying over a bit more when over-cammed and/or over-revved. Garbage in.. garbage out...can't polish a turd.. and all the rest.

Point of all that.. take it from someone who's been there and sees many in the same boat every year.. save your hard earned cash and start out with a street/strip style head to begin with and work your way up from there. Then if you still want more power(+RPM) down the road a ways?.. port those 205's and you'll end up 3 steps ahead of where those puny little e-brock's let you down.

Rockers.. you'll want 1.7's on the intake at the very least. Whatever head you end up with.. and especially if you use a split pattern shelf cam.. my advice is that if the exhaust port is stock location or smaller/unported.. use the 1.7 on the exhaust as well. If it's raised even slightly and/or is considerably larger than a stock port/ported(CNC or otherwise).. stay with the 1.6 RR to slow down closing and keep the exhaust valve near the seat a tiny bit longer to promote improved velocity at EVC. That's why splitting I/E ratio is pretty common at the higher levels and always based on the engines design.

A carb spacers required spec is dependent on the whole shebang. Cam, head, intake manifold size and rpm range.

Another word of advice is to get yourself a premium polished/treated valve-spring rated for the cam AND its valve-trains mass(Ti retainers.. werd).. rather than the cookie cutter crap that usually comes bundled with some "complete heads". IF.. you go with complete heads.. always spec to the next valve spring up(stiffer and/or higher rate) to reduce the total pressure losses associated with those marginal springs after the first season. Don't forget the nice stiff .080 wall push-rods either.

Don't overlook the others either because trick flows heads are killer too. Moving factory valve locations is really good for the small bore motors. But then of course.. valve notch locations present that next hurdle.

Spin it and feed it. Build it right.. build it once.. and you'll get well more than your moneys worth out of the deal.

And.. STOP! Now.. quickly back away from the alphabet cam. lol

 

Ill probably have to read this like 20 times to get all the information, from the first read through i got stick with afr 205 or look into trick flows and build from there later and stay away alphabet cams lol

 

haha.. pretty good for a once over. you nailed it.

 

The cam is a have to change deal and as far as heads go. A buddy and I built a 342 stock block mustang that ran 6.80 1/8 with afr 185 heads. And it was a street car with a lot less than .600 lift on the cam. And it was on 93 octane fuel. But If I had a dart block. I'd build a bigger cube motor with 205 heads and call competition cams or the like to get a cam and valetrain recommended. Generally with the cnc ported heads they flow so well down low that a giant cam generally isn't needed.

 

CNC heads love high valve lifts and can often get by with a reduction in duration due to the greater/improved area under the ports flow curve

 

That's not what AFR or Competition cams told us. And our cam was around .550.

 

Alphabet cams arn't bad, for paper weights. Look into a custom cam, instead of an off the shelf cam. Tell the can grinder what you have and what you want to get out if it and they'll reccomend the supporting valve train and a head reccomendation as well.

 

Agree 100%! Just too many potential combinations out there and a custom cam pulls your specific combo together for more polished performance. Plus.. an extra $100 bucks can easily be worth 20 or more peak horsepower and more importantly.. power everywhere under the curve(fatter and/or wider powerband).

Not sure what to say.. other than maybe that specific question wasn't asked? I just mimic and try like hell to copy the best world class engine builders while I drag along on their coattails.

It's like this.. and Mamo would agree.. more air in faster means the valves don't need to be left open any longer than required to feed the cylinders requirement. Unfortunately.. it's tough to design and hard as hell on a valve-train dynamics to get .700 lift out of an RV style lobe design. Which is why you won't see many floating around. Plenty of guys running ridiculous amounts of rocker ratio(1.8 - 2.0+) to emulate its effect though. To generalize and over simplify.. lift(total and how fast you get it) affects overall power under the curve.. and duration affects the actual width of a powerband. You obviously need both for best effect. Ideally.. we have a cylinder that can be fed huge amounts of air in the shortest time possible.. but unless you force induction.. gravity is a bitch and these things take more time, more rpm, more duration, and inertial mass(5th cycle/scavenging effect/inertial tuning) to pack more air in before IVC. It is.. what it is.


Guys.. here's how I sort my way through the builders jungle. I’m usually thinking it’s always best to keep in mind that not everyone who answers a phone is an expert engine designer and/or master head porter, right? If you don’t believe me?.. call Summit or Jegs for advice. Lol The person who picks up the phone surely works for one of those companies but it’s sometimes like drawing straws to find someone who’ll help us work towards that last 3% in our build. There’s no magic pill for weight-loss and no one can build your motor over the course of a single phone call. And then there’s the .. "if we only had a nickel" for every time we’ve been mislead over a telephone. Now, I can’t speak for everyone.. but money’s pretty tough for me to get and the sacrifices made to get it are often high, so I don’t usually part with mine very easily. There’s just too much room there for errors, between the line readings(whether any text is present or not), misinterpretation, and miscommunication for my hard earned dollar. And as is often the case.. it’s not actually their money on the line here(that specific person at that specific moment and on that specific day/call back 2 days later to see if things change at all).. they’re just there to try and collect your cash and get their paycheck by the end of the whole process. Capitalism in all its glory. Not to say that you can’t call the major players involved here and get good info/rec’s on the products they sell.. if you can’t then those people should be looking for other jobs.. just that there are unknown variables there, is all. The actual head/cam designers or builders probably don't answer the phone very much. Takes extra persistence, time and tact to squeeze those guys for detailed information.


Main point is this. By all means possible you should talk to at least 3 cam mfgrs and 5 head mfgrs to gain some perspective on the above. Even do it several times over a few weeks to help weed out any “scripted cookie cutter recommendations”(ie; Jegs/Summit). I’ve done it many times and you’ll likely still be a little confused for some or maybe all of the various reasons listed above. Then you’ll see the trends and acquire some of the bigger pieces so your combo puzzle can suddenly take shape. It’s obviously your time and your cash involved here and it all just depends on how far you want to stretch those two investments, is all.


BUT.. and this is a big ole’ butt.. even after talking with the sales and parts guys.. I myself ALWAYS talk and listen to the guys who are actually racing and testing a particular combo in the real world(as in the previous posters reply above). A dyno is just another tool that a business often uses to make more money and will lure you in without truly showing you what the combo will do when real world dynamics and physics are involved. Happens all the time on every single day of the year. Also take a quick look at the various racing classes to school yourself as to what the best of the best actually is for a particular power level you’re interested in achieving(don’t be too overzealous or delusional about max airflow/power/speed gains and keep goals more realistic to end up with best results). And then the forums will give you the smaller detailed pieces as to how they got there throughout their buildups. That’s only if you’re willing to read more than 10,000 words to actually find it though. lol Even engine tech sections in forums like this one are a good place to accumulate the puzzle pieces. Plus.. there’s plenty of dyno tests out there in webland with back to back comparisons of same head but in different port sizes without any other part changes. Also consider sources, who’s doing the actual testing and of course be mindful of motives involved for doing it. I know that David Vizard(guru) has really good articles and did a test on Dart’s stuff(in his head porting book) which you can probably find on their site. That’s the kind of stuff that teaches and gives you a good overview so you know who’s turning you in the right direction.. and even more importantly.. who’s steering you in the wrong one. An ounce of prevention can be worth money and horsepower.


Hope all this rambling hasn't been too incoherent and helps steer you in the best direction possible for your dollar. Good luck on the info hunting.