BTW this is my first ford build so bare with me please.

 

You'll get lots of opinions on this - so here's mine! Any intake runner volume above 185 on a stock bore 351W is overkill and will actually hurt performance. So between your two choices, the AFR185 is better. With that said, you might want to upgrade to a Performer RPM or RPM Air Gap intake, as your regular Eddy Performer intake will now start to choke the AFR185s, since its very similar to the stock intake.

 

I understand that 205s is a little over kill for a stock bore 351W but what I'm doing is using the heads and cam and intake on this engine until i can afford to invest forged bottom end on my spare 30 over block that i'm trying to build a 408w. I dont wanna have to buy two sets of heads i guess is what im getting at.


Also after looking at my intake box it is a Edelbrock Performer RPM intake.

 

Between those heads, I'd go with the AFRs, and not because a 205 is too big for a 351 but because those E street heads are proned to problems. Personally, I'd go with a Twisted Wedge 185 or 205, but you'll get a lot of opinions on heads. As pointed out, you may want to look into a different intake.

 

Great video. Runs great man. Do drive it on the street much are just the track?

 

Hello justin04

My current setup is a 351 W stock bore. I've added a Holley Carb, Headers, Edelbrock Performer Intake. I'm currently in a debate on to buy a set of edelbrock E 205 heads (5028) or the AFR 185s'? what I'm doing is using the heads and cam and intake on this engine until i can afford to invest forged bottom end on my spare 30 over block that i'm trying to build a 408w. I dont wanna have to buy two sets of heads
Also I'll be adding this cam to the mix.

http://www.summitracing.com/parts/lun-10350703lk
http://www.summitracing.com/parts/edl-5028

One of the problems you are going to encounter that no one has mentioned yet is that when you try to use the E205 heads on a 408 stroker your compression will be WAY too high if you use the kit with flat top pistons. The E205's are 60 cc's which calculates to around 11.36 static compression with a std height block and around 12.0 on one that has been "0" decked like yours might be close to in the end.

82 CC' heads give you around 9.6 which is much closer to what you need with flat top pistons IMO depending upon cam selection. Others opinions will vary. Ask a professional engine builder to calculate the best final "dynamic compression ratio" for you. This number along with your other specs determines the size of the cylinder combustion chamber.

Using 60 cc heads on a std height block, 408 stroker and pistons with a 25 cc dish will give you around 9.4 static compression.

See compression calculator below.


United Engine & Machine Co. Incorporated



PS - I would use heads with a runner bigger than 185.

 

Hello justin04




One of the problems you are going to encounter that no one has mentioned yet is that when you try to use the E205 heads on a 408 stroker your compression will be WAY too high if you use the kit with flat top pistons. The E205's are 60 cc's which calculates to around 11.36 static compression with a std height block and around 12.0 on one that has been "0" decked like yours might be close to in the end.

82 CC' heads give you around 9.6 which is much closer to what you need with flat top pistons IMO depending upon cam selection. Others opinions will vary. Ask a professional engine builder to calculate the best final "dynamic compression ratio" for you. This number along with your other specs determines the size of the cylinder combustion chamber.

Using 60 cc heads on a std height block, 408 stroker and pistons with a 25 cc dish will give you around 9.4 static compression.

See compression calculator below.


United Engine & Machine Co. Incorporated



PS - I would use heads with a runner bigger than 185.

Thanks for the advice. I'm still unsure what head i could run that would be middle ground for both engines. I would go to a professional engine builder but seems like in my area all we have is 4 banger shops.

 

Twisted wedge here! Can't beat them and they are one of the lower priced for an aluminum head.

 

I wouldn't go below 10:1 static compression on an aluminum head n/a engine.

 

Get with a competent shop, pick out the optimum heads for your 408 (TW 205 is a proven head on these setups) and the piston you need to achieve the desired static compression. Lots of options between true flat top (which is what I have with 64cc chambers and slightly above deck) and pistons with 25cc valve reliefs. More than likely any 20+degree inline head you pick out is going to require you to run pistons with some type of valve reliefs to avoid PTV, I'm just an odd duck with my 10 degree N351 head and can run a true flat top. I would want to stay in the mid 10s, especially with an aluminum head, I'm close to that with my iron heads. Pick out the cam that fits your needs and your parts.

Buy them as you can afford them and keep them safe and pretty in their little boxes. Once you have everything, build the awesome 408 of your dreams. Save the compromises for relationships...having one engine with too much head (never thought I would write that...no such thing...) and the next one with too little (oh buddy) and....never mind, you see what I mean. Build it once and build it right.

Take off yours and home port them for fun and enjoy the learning and build a screamer on the stand. Maybe pack a few lunches and pinch a few pennies to get there faster.

Email Ed at FTI or call Woody at Fordstorkers...they both sell these parts and can help you plan even though they may not be near you...can't tell where you are.

I used Ed and had a great experience. Don't expect him to coddle you, but is very knowledgeable.

 

I only play an expert on TV, but I'm a little lost on the compression differences/benefit ratio between a 351 and a 408...I've only ever heard people speak of iron/aluminum in regards to the detonation factor.

The compression is just a calculation of head chamber volume, head gasket bore size, head gasket thickness, piston down bore from TDC and Volume above the piston.

How does the rod length and crank size affect detonation in a 408 that it wouldn't in a 351 when the factors that differentiate the two has nothing to do with compression calculation?

Couldn't you have the exact same compression on both motors if you used a piston with identical valve reliefs, same size chamber in the heads, same gasket thickness/bore size, same block deck height?

Edit: Just checked DSS Racing website...they offer -3, -18, -31 dished pistons in their kits. Custom dish piston is an extra $180.00.

 

Just checked DSS Racing website...they offer -3, -18, -31 dished pistons in their kits. Custom dish piston is an extra $180.00.

Ok, cool, looks like you can run 60 cc heads on a 408 std height block using the 18 cc piston or the 31 cc poistons on a 0 decked block and mill head as necessary if needed to get compression where it will be best for your set up. But as I suggested please check with any good builder somehow.

I only play an expert on TV, but I'm a little lost on the compression differences/benefit ratio between a 351 and a 408. Couldn't you have the exact same compression on both motors if you used a piston with identical valve reliefs, same size chamber in the heads, same gasket thickness/bore size, same block deck height?

Not to worry, I stayed at a Best Western last night, lol. Do a google search for uncorrected compression, dynamic compression and cylinder cranking pressure. You can also play with the calculator in the link below and it will show you what effect changing different things have on compression. Just use 60 where it asks for intake valve closing time. Unfortunately that calculator doesn't generate a number for cylinder cranking compression like some others do so you will need to use a conversion chart for that.



United Engine & Machine Co. Incorporated

 

I leave dynamic compression up to Ed. (Cam grinder)

I know the crank size goes up for the stroker but the rod gets shorter, right? Should effectively cancel each other out, right?

 

No,l your friend ED could explain uncorrected compression to you also but here's a simple explanation. Rod length is irrelevant for uncorrected comp.

Let's say engine an engine has 10.0:1 uncorrected comp. If you increase the stroke only [distance piston travels] the uncorrected, dyn comp and cyl crank pressure all increase. If you increase the bore size the same thing happens. This is because you are trying to squeeze more volume into the same size cyl head comb chamber.

 

I see where crank is listed for static and rod is listed under dynamic so they aren't in the same equation. That I understand. Checking my desktop dyno software, the crank is factored in to calculating compression, is that adjusted compression or some other compression.

That's why I let my builder sort this out for me.

 

I see where crank is listed for static and rod is listed under dynamic so they aren't in the same equation.

Oh sure they are, it's just adding rod length and ivc to the other numbers, lol.

Checking my desktop dyno software, the crank is factored in to calculating compression, is that adjusted compression or some other compression.

It starts getting complicated.

That's why I let my builder sort this out for me.

Even though I can do it that's what I suggest to others after making them aware of it unless I am the one building the engine for them.

 

Edelbrock makes pre dyno-ed Top End Kits, find out what they package with their performer intake, (heads and cam), then you know what it'll make beforehand,.....and be getting advice from them, the experts on their own equipment. :thumbsup:

 

Well, according to the United Engine calculator, I have 10.475 static compression and 8.883 dynamic (my intake closing point is 56, so you were very close ).

I guess that puts me in the street/strip category that I was asking for.

 

Well, according to the United Engine calculator, I have 10.475 static compression and 8.883 dynamic

Pretty cool huh? That = 181.9 cylinder cranking compression, it will theoretically detonate on 93 octane. Aluminum fast burn heads will help, iron heads should detonate and need higher octane.

(my intake closing point is 56, so you were very close).

Most medium size street cams are around 60 so that was easy, lol.

I guess that puts me in the street/strip category that I was asking for.

Does your car run? Alum or iron heads? Reg or race gas? Any detonation?

 

It's still on the stand. Iron N351 heads. May have to give the 93 octane a little help.

We will find out about the detonation b

 

It's still on the stand. Iron N351 heads. May have to give the 93 octane a little help.

Unfortunately the best octane boosters have been proven to boost octane by only around 2 points, lol.. Do a google search for octane boosters. You might use some toluene or methanol if needed, search that also.

 

These heads need less timing than some, under 30 most say. Will that help?

 

Unfortunately that is not an easy question to accurately answer either IMO. I wouldn't worry about it until it runs. Those heads might be able to tolerate a bit more compression than orig heads.

 

what about mixing E85 and 91 (that's what most pumps have around here and we have lots of E85 pumps nearby).

12 gallons of 91 and 7 gallons of e85 put around 96.2 octane level.

 

Well that's a cheap easy way to start, might work but you don't know if you have a problem yet.

 

I'll fire up the ole' google...but how do you know if you have a detonation problem...besides something going bang.

Never mind...lots of information on the interweb.

 

I'll fire up the ole' google...but how do you know if you have a detonation problem...besides something going bang.

The only way to know for sure is by buying a $6000.00 deto sensor or getting a sonec tester like the LS1 eng's have. The eng will ping if it has noticeable deto however all deto is not loud enough to hear.

 

I wouldn't mix E85 with gasoline. I'd just run E85.

I've had great luck mixing 1 gallon of toluene per 10 gallons of gasoline.

But for a street engine I'd just build the 408 with dish pistons. You can get a 10.19:1 compression ratio with a -22cc dome and 61cc heads.

I like TrickFlow heads. Those Edelbrock heads look like a good deal but they look like a 351w version of the E-Street heads and those have some issues.

That cam looks like a decent street/strip cam for a 351 but it will be more street in a 408, luckily cams are cheap.

 

I haven't looked at the store yet, but my light reading made it sound like toluene was hard to come by here in the Meth capital of the U.S.

I agree, TW 205 408 and the right cam would be a beast. Agree with your thoughts on the Eddy heads too.

 

I haven't looked at the store yet, but my light reading made it sound like toluene was hard to come by here in the Meth capital of the U.S.

Ahhhha, supply and demand I guess, lol. I thought that was Portland, Kurt Cobain's home town, lol.

 

Well, Missouri is number 1, but we are top 5. And at the bottom for obesity and education...yeah us.

 

You ain't got nuttin on us down here in LA and MS, we're neck and neck for all that is bad.

 

I used to get toluene and xylene at Home Depot. Xylene also works similarly well at the same ratio. It's been years since I checked to see if it was there though. And by years I mean over a decade.