408 Stroker build
 

Ok....I know I may open up a complete can-o-worms.
Looking for some suggestions on stroking a 95' 351w block. I just purchased the block and getting ready to take it to the machine shop to have all the work done. Im looking for suggestions on rolling assembly, heads, cam etc. This will be a street machine, just want a good sounding engine while at the stop light but have some grunt to have fun with the folks that spent a lot of money on their production cars. So far I looked into the SCAT forged rotation assembly with I beam rods, and wondering on the heads......AFR 205's seem to be the popular item but, im not doing any track work and wonder if its worth the extra money for me?

To make more power you have to burn more gasoline, per unit of time, at the correct air fuel ratio. Putting fuel in is easy. Putting more air into an engine, is not. Talking normally aspirated, more cubic inches is king. More cid moves more air, until you reach a size that the valves and ports become the bottle neck.

For any given bore, there is a limit on how big of valves you can fit into that space. A long time ago people, quit thinking 2 dimensional, and realized that if you change the angle of the valves you can fit bigger valves into the same bore size. The hemi is the ultimate canted valve design. The 3 and 4 valve per cylinder heads have proven to be better, when considering emissions, but now I have digressed.

In my opinion, the heads make the engine. When I was a puppy, there were very few head options and the cost was more than a pup could afford. Access to a mil to port factory cast iron heads was hard to come by. Therefore we were forced to go down the road of ridiculous cams. You do not have to do this today.

Your only problem is to pick the right heads for what you want your engine to do. Now for the bad news. The biggest, baddest, highest flowing, Hp making heads, are not the best heads for every engine and its intended use. What! A mid range head may be a better head, for a desired engine personality.

You may have already thought all this out and just have not shared it with us. Picture a dyno chart. Now remove the Hp trend line, and forget about Hp. Now what you have left is the Torque trend line. What shape do you want that line to look like? Are you willing to give up tons of torque on the low end to get more torque high up the rpm scale? How many rpm are you willing to turn?

An engine that has a torque curve that looks like a mountain (peak torque at a very narrow rpm range and falling off rapidly on either side) is absolutely no fun to drive on the street. They can make huge power, but only in that rpm band, at very high rpm.

On the other hand, a flat toque curve (same torque at every rpm used) is the easiest most friendly engine to drive anywhere. You get the exact same pedal response at any rpm. The problem is this engine has yet to be designed. You have to give up something somewhere to get more where you want it. Picking the right heads with the right cam is how you balance this out.

The other two factors you have to consider are rpm and idle quality. Idle quality goes hand in hand with street manors. There is that nice rumpty rump idle that is music to the ears, but too much and you have an ill mannered engine that bucks and hops when you try to drive slow.

RPM goes directly to longevity and cost to build. The more rpm you want to turn the stronger the bottom end has to be and harder it is to control the valves. Where do you want the Hp to peak (at what rpm do you want the torque to start dropping off faster than the rpm is increasing)?

Once you lay this out, a builder will know what heads are best, but I do like the AFR heads.

For your application, you don't need a forged crank. You won't be spinning it that high, or putting that much of a load on it. That will save some dough.

Here's an excellent rotating assembly for $1,700. Pay the extra $200 for balancing, it's worth it. http://fordstrokers.com/stroker-kits...ating-Assembly

My 427 stroker made over 500 dyno proven rwhp on out of the box Dart 195 heads. The torque curve was about as flat as a table top from about 2,500 to redline. They are an excellent product, with a lot of bang for the buck. Other heads will make more peak HP, but you'll give up low end torque. Low end torque is what you want in a street car.

Comp cams makes some excellent off the shelf cams depending on the intake system you plan on using. I highly recommend EFI. I don't own anything with a carb.

Dart Renegade 195 would be good for a street 408 build. Air Gap RPM manifold will make torque thru out the RPM range

Lots of great info. Thanks for the help and i am sure there will be a lot of upcoming questions. I was wondering about the cast crank......Its always easy to make a mistake thinking I need the most expensive strongest parts only to realize that I wasted money on a part that my particular application will not break. unless someone can talk me out of it I am sold so far on the cast crank to help with saving money for the parts that are better suited to spend extra!!!

Did you mean AFR Renegade 195 heads?

heads
 

Looking at the heads......Seems that the AFR 195 and the Dart 195 heads are the same price.

There are a couple well advertised cranks, and one of them has a nasty reputation for breaking. Several builders have said they will not use that brand. I cannot remember the brand so will not say. Do some searches and you will find what I'm talking about.

Also realize these days they are cast steel cranks. They are quite a bit better than the old factory cast iron cranks back in the day. There are things that can be done to a crank to increase strength. Radius verses a sharp corner. Grinding verses cutting. Shot-peen surfaces.

You definitely do not need a crank machined from a forged billet of steel. That's a lot of money better spent on the heads.

Yes, AFR heads. Have them on a 427 Windsor Dart block motor.

I had AFR 205s on a 421 c.i. Windsor 4.045 bore x 4.1 stroke. Vic Jr and a Demon 825 cfm. About 10.5:1, .600 lift 250 duration.

Lots of low end power, ran well.

Jim

so far
 

Im thinking the money I saved by going with the cast scat rotating assembly, im going to put towards the head. Leaning towards the AFR. So what should I go with? 205 72cc or the 195 72cc? Like I said before....im looking for a street machine.....fast off the line when I want to mash the gas and a good healthy sound sitting at the light. I want enough rough idle that the car wont be too jerky at low speed....most likely going with the TKO 500

I have the 195 heads on my 408. I don't recommend just buying them stock and slapping them on. Get a set from blykins on this site, or from a reputable builder. They will buy the heads bare, then build them correctly, checking everything. Ask me how I know this is important.

Once you pick out what you want, call blykins and tell him what you want in a cam. He will get you a custom grind that will match your heads and your intake.

Scat rotating is fine. You don't need the 205 heads for street use on a 408. You could go with the 205 if you are going up to 427 just to pound your chest. Anything you put in these light cars will be fast enough to kill you at any point when you forget what you are driving.

Decide on a block, rotating assembly, and heads. Then go to one of those online calculators to determine what type of piston (dished, flat, domed), what thickness head gasket you need, and what size combustion chamber to get you the compression ratio you want. I recommend 9.5-10.5 for the street. Any higher than that and you may need to find race gas.

I tried EFI and went back to carb. That was a total fiasco. I don't recommend the carb replacement systems. If you choose to go EFI, go with a multi port system. YMMV.

Thanks Texasdoc.....I will look into that for sure.

Buy your heads from Lance at craftperformanceengines.com/


Craft Performance CNC Ported Cylinder Heads, you can go wrong.

We have bought a couple of crate 408s that made 530 hp 540 tq from Craft.

Ask about the cam he uses in the 408 and buy it from him. Great street manners but when you push the gas pedal, hang on!

I bought a pair of Craft Brodix heads for my 302/354 and picked up 80 rwhp & rwtq. Dyno proven before and after.

The crank that were breaking were Eagle's FE cranks. No problems with the 408 cranks.

Dwight

trying to locate blykins. tried a search with no luck

His name is Brent Lykins.
Company name is Lykins Motorsports. I think.

Great!!! found it. I will be giving him a call. Look like from Texas doc, my plan of buying afr heads and bolting them on could be a bad choice.

As said above, all depends on what you plan on doing with the car. Brent will steer you the right direction, so make it worth his while and purchase some of the parts he recommends from him.
My 393 stroker is very similar to what you are looking for in your 408. I used a Comp 294 Extreme Energy cam , Comp roller rockers/spring kit sized for the lift (important), Vic Junior heads, and a Scat 9000 rotating assembly. Weiand Stealth intake (clone of a Air Gap) Standard pressure oil pump and don't forget to get the correct rotation water pump for the belt configuration and accessories you plan to run. Don't ask me how I know this.... :)
Ask Brent what he prefers in balance. I used a standard 28 oz balance on mine and everything worked out great and it runs like a beast. Very lumpy at idle, picks up power at around 2500 RPM and goes until I chicken out. However, in town driving is a little irritating in traffic. If I had it to do over, I would go with a slightly smaller cam like the Comp 282 or a custom grind and I would (and may still) go with fuel injection. The new Fitech system and the Holley are reputed to be incredible and pretty much self learning as long as you can swallow the up front cost.

Good luck with the build. The engine was my most enjoyable part of the build.

Bob

Thanks for the info, you answered one of the questions I was going to ask. Im going to use a cast crank and wondered about external or internal balancing. It too easy to spend money that in not needed unless you are hitting the track and build a high HP engine. Getting sucked into all the hype is very easy!!!

texasdoc...sent you a PM. Im in Keller also would love to see your cobra. Also, did you purchase the complete scatt rotating assembly or Crank, rods, pistons etc separate? Internal or external balanced?