wondering what you guys think of this combo...i havent put it together yet so i am up for some advice or pointers...but either way tell me what you think.


406

11.8.1 mahle pistons..(very light) ( going with 58cc chambers on heads to try and bump the compression around 12.5.1)

eagle 5.7 i beam rods

scat crank

camshaft = not sure the exact numbers but its got .627 lift with 1.5 rocker , 3000-7000 powerband ..wants a 12.5.1 compression

bowtie high rise intake

barry grant 850

so now for the heads...this is where i really would like some help

i am stuck between dart iron eagle platinums or brodix track 1
i can get them for about the same price , i know everyone loves aluminum but my engine builder swears to the dart heads . from looking online they flow alot ( more then the track 1) ...tell me what you guys think..i am also unsure if i should go with 215 cc runners or 230....the car theyre in has a 4.88 gear and will be tubbed out... tell me what you guys think ..what kind of power should i be making

 

Not sure what that is. With the RPM range of the cam you're talking about, I think I'd do something like a Victor Jr. and keep the RPMs above 4000 from the get-go.

 

Heads. The AFR eliminator line is sure looking good from what I have see. I would not go less than 195cc. For your motor the next size up might be just right. I would call them.

The new Dart Platinum line is supposed to be pretty good. I have not seen anything on them though. If interested give them a call.

 

that compression with iron heads is gonna be rough and need alot of octane Can you even mill those heads to 58cc?

I'd go with aluminum track 1's. they flow alittle more from what i seen, abit more on the exhaust i believe as well but thats the track one's 221 cc intake vs iron eagles 215cc. i'd keep a 215-220 cc intake for that setup so either head will work fine. I'd go aluminum for weight savings and to keep detonation down

 

the intake has approximately the same rpm range as the victor jr and puts out very similiar numbers from the magazines i have read....as for detonation with iron heads, its an all out race car so at all times it will have cam 2 in it..( not sure the octane number , 108 or something?).......i am trying to make sure everything is matched up well if so i am expecting mid tens?....not sure what the car weighs ..its a tubbed out 87 trans am dana 60 4.88 , 12 point cage...the doors have been gutted , everything in dash is gone just have aluminum with guages now .. racing seats ..and anything in the engine bay that is not needed and robs horsepower is gone..i am guessing the car weighs somewhere just below 3000..that 406 ..turbo 400 tranny.5000 stall ..4.88 dana 4 link in a 2900 pound car....goal is 10.5's

 

AFR heads is the way to go.. here is the set up i ran for 11.30 q mile times. 406 sb afr 220 heads.weiand team g intake. holley 926 cfm carb. custom ground solid roller cam. 565/572 lift. th350 trans 4200 stall. 411 10 bolt.. 74 camaro. stock 5.7 rods and kb pistons.. 11.30 at 119mph. street car... 3280 lbs

 

If you want to make all that power and spin it that high with an all-out race engine, I would reconsider on the con rods. Cheap Eagle I-beams aren't going to last long a 7k rpms.

Also, I hope your crank is forged as you don't specify.

 

i would love a set of afr heads but they are just way out of my price range.......as for the eagle rods they are said to be good to around 7000 ( who knows for how long though) but at the same time i will probably be shifting it around 6500 or 6700....if those rods can get me a season i will be happy...i plan on getting h-beam rods and a forged crank next year so i can really crank the rpms

 

if you go with I beam rods make sure you upgrade the rod bolts to ARP hardware... maybe even the L-19 bolts. Thats the weak point so make it strong

But i agree if you can upgrade the rods for safety purposes.

that compression and that cam will want to make some power and will create some stresses. Its great tho that you have lightweight pistons, that will help alot.

I still think if you can get the Track 1's for a good price, go with it. Just make sure to match the valvetrain to the cam you intend to use. 50lbs of weight savings also helps alot.

you should EASILY have mid 10's on motor with 2900-3000lb car with those heads and a big solid roller. I like the lift in the that mid .600 range, now just match duration to have a peak rpm hp at 6800 or so. That should be all you need.

 

yeah the rods have the arp connecting cap bolts...although something of concern , i guess they had a little bit of clearance problems so they actually had to grind off a little bit of the corner where the the bolt connects the rods...as for strength and where its at on the rod i am sure is not an issue but what about balancing? i would think they would need to be re-balanced. the guy who did it is not an engine builder but he does build engines and said it would be fine...what do you guys think?

 

depends on how much is removed, it may not make a difference. I'm not sure how tight a tolerance engine builders like to get, but i wouldnt think a gram or 2 of weight would make a difference

ever consider a smaller base circle cam?

 

what do you mean exactly? lol i am a little unfamiliar with that

 

cam ground on a smaller circle so you get same cam specs but more clearance with the rods.

i think stock cam specs are on like a 1.25 inch base circle, meaning the lobe circles are 1.25 inch in diameter. My stroker cam is ground on much smaller base circle, like .900 or somethign i havent measured it. Gives more clearance and sometimes you can get more lift out of it

 

THis is NOT a street application. Go with the BIGGEST heads you can get. With that cam, compression, and 406ci it will take ALL of the Cylinder head you can give it! Go with some DART Pro 1 Platinum 230cc with 2.08/1.625 valves. You will be knocking on 600hp's backdoor...Probably more like 560-570hp. But more could be had with some minor work.

 

what is the rpm range of a 230cc head?

 

alot of rpms. i think you spin a 221cc Track 1 up over 7000rpm but i dont think you'll need to. You should have mid 10's without goin over 7K if you pick the right cam

 

The 230cc will STILL make more power UNDER, over, it doesnt matter, 7000rpm.
You are NOT porting the heads, CORRECT? The heads will still be your bottle neck.

 

I'm just worried about port velocity and his torque curve. i do understand this is a race car but alittle bit of midrange torque will help him launch harder to run those better ET's. To get mid 10's at that raceweight you will only need 450-475whp.
Those 230 Iron eagle platinums are said to flow 308cfm at .700 tho and abit over 200cfm on the exhaust side. Thats a alot more than i thought, and alot more than the 215 cc head they have.
Track1 base head is 221cc and flows 280/190 at .700. So those iron eagles have an edge. But for Ultimate power/torque i like the AFR 210's with over 300cfm with a 210 cc runner. Velocity and flow is a great thing

If you go with the big head you'll need more stall speed and gear. I think either head choice will be fine for what you intend to do tho.

 

its big bad 406ci. I CANNOT put a BIG ENOUGH head on it. He may be shootin' for mid-low 10's, BUT I bet he'll be happier with 10.20-.30's.

 

true better to go overkill then than not enough.

 

Besides, you can always back off on the cam a ****-hair, a get that low speed torque back. Then next year when he's ready to run, he could stick a 276/284 @.050" in there with a 5500 converter, shift it around 7200-7300rpm and run some 10.10-10.20's. Who knows it possibly break into the 9's in this form, but I doubt it...Probably 10.3's. With something along the lines of 262/268 or so it would probably go 10.60's....Maybe quicker depending on weight, track, weather and tuning.

 

this year the heads will be unported... the cam i am using is not one specifically picked out perfect for this motor...the duration is ( not exact but really close) 250/ 258 @.050 . ill have the compression and everything matched but its not " perfect" ...... .630 lift....but i am actually going to be using a 1.6 rocker i know that will make the lift to about a .670 , but how does this affect duration and would you advise for the 1.6 or would you be against it...i figure if i go for a set of 230c heads the larger runner will like that higher lift...plus even if it is a bit too much for me this year due to the fact that i will be shifting just below 7000 , next year i will be upgrading to h-beam rods so i might as well get it set now

....but i also think i have plenty of gear ( 4.88) and enough stall ( 5, -5500)

 

yeah go with the 230 now then and that cam wiht 1.6's. it will add abit of duration but not all that much. The heads will love the extra lift

then you can port the heads for serious flow and run a bit bigger cam and really get moving

 

i am just hoping that with the 1.6 they dont up my duration a bit too high , out of my powerband or to where i need more compression....the dart 230 heads actually come in 72 cc 64 cc and 49 cc.....i originally wanted to buy the 64cc and have them milled to 58 because i was a little afraid of the 49cc...i think with the 49 cc that would up my compression to 13:1...but do i really have anything to worry about with that small of a chamber? i guess the only thing i am worried about is the valves hitting the piston

 

yeah piston to valve clearance would be a big concern. And you would need to make sure your quench height is .035-.040 and no more.

 

thats an area i dont understand...how exactly would ihave trouble with piston to valve clearance at 13:1 while other motors can be up to 14:5:1 ...what is different...i understand pistons may have deeper dishes or something but i am still lost... could someone explain..

 

its all about the piston specs and your chamber size in the heads. you can run smaller chamber heads with flatter top pistons to get 13 to 1 compression but the valves would be so close to the piston since the chamber is so small. But some motors run alittle larger chamber with dome pistons that have some valve relief and the valves are higher off the pistons and still clear fine.

it all depends on the cam specs/timing events and the amount of room you have between the piston and cylinder head. I dont know how you can know for sure if someting will work or not without measureing a few things.

 

ok that makes sense.that was actually alot simpler than i thought it would be....hopefully those heads can be milled to 58cc so i can get 12.5.1 ....i think that should be pretty safe...the pistons are flat tops but they have real deep dishes

 

If you are running a flattop piston, then by all means go with the 49cc chamber.
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also the 1.6 rockers will only add about 2 degrees of effective duration at most. No need to worry about moving the powerband to high.

 

so a flat top wil have no problem with a 49 cc head? that makes sense...especially when you consider why would they even make a 49 cc head if they could not work ...especially considering the flat top is the lowest your going to get ( say against a domed piston)

 

Yes. That IS THE POINT of the 49cc chamber. It is designed for Flattop circletrack engines.

 

how about for a dragracing engine lol

 

i still want to think piston to valve clearance with a big solid roller could pose a problem and will definately need to be checked

 

You DO NOT NEED TO WORRY! Its the chamber design. Its not like they have been milled to get that volume. You would need to go AT LEAST .700
0" lift before you EVER needed to worry about gettin' into trouble.

 

chamber design or not, 49cc will keep those valves close to the heads. thats a TINY chamber

 

hmm...well the pistons are 11.8 with a 64cc head ( so i am not sure what that 49 cc head would make) and the camshaft lift will be .667 with the 1.6 rocker

 

"IF" the 11.8:1 is right with 64cc heads that would give about 14.3:1 with
the 49cc heads. (These are static not dynimac numbers) That cam will
"Blow Off" at least 2 (from 14.3 to 12.3)

 

zipfast....

......what do you mean by the cam " blow off" and so would that mean i would have 14.3:1 compression or 12.3:1 ?

 

cam will open the vlaves at a certain point so the chamber will never fully compress to the static compression level, it will only reach a peak point and never increase any more. That peak is your dynamic compression and will be determined by your cam valve timing events

 

You will have around 14:1 with the 49cc heads. Do it. 230cc 2.08/1.60 valves and 49cc chambers...get the 1.625" exhaust valve if you can find them...I know they sell them with the big ex. valve in 64cc chambers.

 

now i may be totally off here , but when you say the 14.3 static compression and what not...would that only occur if the piston hit top dead center and the valve was completely open at the same time? ....and since the cam timing is not perfect to where that happens at the same time it actually happens to where the piston and valve are closest together would actually be measure at 12.3:1.....sorry if that did not make sense , i am kind of a newbie ( only 20 years old , all my knowledge i received has been from reading books)

 

its 14.3 if its full compression stroke to TDC with valves closed. But since they are NOT, cause the cam is opening them before TDC, your actualy effective or dynamic compression ratio is lower, say 11-12 to 1 or w/e based on your cam specs, since the valves are letting some of that compressed air out

 

ok yeah that makes more sense ( the valves being closed part) i appreciate all this information someday i would like to have my own little shop ( long time from now , still got a lot to learn) its always alot easier when ya got someone explaining rather than just trying to interpret from a book.....so my static compression would be 14.3 and my dynamic approximately 12.3...........but when someone usuaully gives you there compression or say when you go to buy a motor in jegs and it says 13.1 , dont they typically give the static compression ratio?

 

yes they give static.

 

well after doing alot of research i found out that the flow numbers on the brodix heads and darts were a little in-accurate..everyone that has had them flowtested elsewhere has revealed the supposed numbers were way off...in the mean time i found a set of bare AFR 210 race ready heads for 700$...i thought it was a good deal and everybody talks afr up so much i had to buy them..they have smaller runners and still flow 299/224...i am very happy with this purchase and really think it will do me much better than the darts or brodix....i really like the 210 runner , since i dont have h-beam rods or a forged crank i really dont want to spin this motor over 6500...maybe 6700 ..well see.....if i can get one season out of it i will be happy..winter i wil upgrade the crank and rods

 

Good deal you will be very happy with those heads. Smart choice.

 

There is more to it than flow numbers. Most people judge heads by how much they flow. The real problem is how does the buyer quantify the heads they are buying? That is one reason some heads are rated higher than they really flow for sales purposes. Those same heads may make more power than the higher flowing heads.

That being said you should be just fine with those heads.

 

yeah i understand that completely...even if dart had 20 more flow numbers on the intake i would still be very confident the afr would be better...i think its pretty obvious that afr makes the best heads out there...not only do they say that , but also the racers ( which is what counts in my book)