Ok, I already have a forged crank for my 406, and now i need to get rods / pistons.

I've been looking at eagle H-beam with arp-2000 upgrade bolts, and looking at trw forged flat tops. My motor will probably be pushing around high 400s low 500s HP/TQ, and I want to build the motor to take a decent shot of nitrous (in case 500 hp isn't enough ) I saw somewhere that I-beams should be able to hold up, with the same bolt upgrades as I would use on H-beams, but im not sure thats true. Also, does anyone have an experience with TRW pistons, good or bad ?

Also, with the rods, i've seen some places saying that you have to worry about the rods clearing the cam, is this something I have to worry about with any aftermarket rod ?

my setup so far is as follows:

dart Iron Eagle Platinum 215cc / 64cc chamber w/ "heavy duty" valve / spring package

weiand Team-G single plane intake
Holley 750 DP
Comp extreme energy cam:
12-679-5
Cam Style: Mechanical flat tappet
Basic Operating RPM Range: 2,800-7,200 RPM
Intake Duration at 050 inch Lift: 252
Exhaust Duration at 050 inch Lift: 260
Duration at 050 inch Lift: 252 int./260 exh.
Advertised Intake Duration: 290
Advertised Exhaust Duration: 298
Advertised Duration: 290 int./298 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.540 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.558 in.
Valve Lift with Factory Rocker Arm Ratio: 0.540 int./0.558 exh. lift
Lobe Separation (degrees): 110

probably going with about a 2500-2800 stall
th350

Let me know, I want to order the rest of my rotating assembly tonight if possible.

 

so much for ordering tonight, come on .... someone has to have some opinions / answers.

 

I'd run the H beams anyway, if only for better clearance with a healthy cam.

 

you always have to worry about rods clearing the cam as far as you need to check it. you'd be a foold to put it all together and not spin it by hand to see if it clears. trw makes good parts, heavy but good. you ought to sit down now and figure out if you're running a power adder or not and select your parts for your application. i'd look at dished pistons instead of flat tops.

 

I would use a good set of I beams like manley sportmaster rods and go with an srp, wisco, je, ross something along those lines for pistons & rods. I beam rod for clerance and weight savings and pistons for strength and weight also. If you are going to use 200 shot or more make sure you get pistons for nitrous. As for cam clerance I was told look for .060 . I also think with your cam you will need more conv. 3500-4000 stall and comp ratio at 10.25 or higher.

 

An H beam is stronger,albeit heavier than an I beam.I think that a good I beam would be my choice,but that's just opinion.As far as pistons,Trw makes a good slug.You might check out Probe's entry level forged stuff.It's similar to TRW,but a little cleaner with the machine work and a bit lighter to boot.
I'm with Ape,if your gonna run pump gas,you may want a bit of a dish.With a zero deck,flattops,and 64cc chambers your looking at around 11.5 compression.I got away with it w/ aluminim heads,but I think iron would put you into race gas territory.
If that cam is available in a small base circle,go with that.It requires longer pushrods,but you should be addressing geometry anyways.

I also agree that you need a lttle looser convertor.

 

so do the H beams give better clearence, or a good I beam. I already have the cam, and they didnt have it in a small base circle, at least that I saw. I don't have the block zero decked, so the numbers that I was looking at were about 10.8:1 for compression with about a 7cc relief flat top, I think that I can get away with this on iron heads, especially with the duration on the cam.

The reason that I'm looking at about a 2800 stall rather than like a 3500 stall is because with this being a 400, theres gonna be gobs of torque down low, no matter what I do, and I'm not building it strictly for the drag strip. My rear end is my weak link right now, so I don't think that I really want to launch at absolute max torqu (at least for now), giving me some room to get traction and then hit peak, just my thought.


back to the I beam / H beam thing, will an I beam be able to hold up well with upgraded arp bolts to about 700 hp (including the 200 spray) @ ~ 6000 rpm ?

 

You will have more clearence with the I beam rods. Trw does make a good piston but they like to cut a groove for the oil ring instead of holes and also they are heavy.

 

Cool, so trw is out, i'll look at some of the other recommended pistons. What I beams should I run to be able to handle this , would the ohio cranks I beams work ?
"
I5700B

SBC

5.700" bushed fit w/ 3/8" bolts

$169
Our newest rod, and a tremendous seller. This is an I-beam construction forged from 4340 [not 5140 as is used in most rods in this price range]. The appearance is somewhat similar to OEM rods. All rods use ARP bolts and nuts, and big block rods are 7/16th."


I would probably have them upgraded to arp 2000 bolts, or is there something better I should look at.



Would I be better running more like a 10:1 ratio for nitrous ? How much would I lose n/a by dropping from 11 to 10:1, I don't plan on moving to nitrous right away, so I want to build the motor to be able to handle its own either way.

 

I also run a forged Scat crank and use Eagle "SIR" rods. You'll still have some clearancing issues to work out regardless of what type of rod you use...

But the build you're doing seems a bit more radical than most. And when you throw a blower or nitrous into the mix, it gets more complicated. Sounds like you'll have a seriously stout motor when it's all done!

 

how much power do you have the eagle SIR rods holding up to, did you do any bolt upgrades ?

When you clearenced the rods for the cam, was it a huge pain, or just grinding a little material ?

 

My 406 was making close to 575 at the crank,and was hit with nitrous on numerous occasions with a 6" set of SIR rods.Any aftermarket rod should come with ARP or the equivelent hardware.I think the SIRs are rated to 500 HP,but I'm not positive of that.At your power level,I'd look into a Manley or other higher end rod.When Ape checks back in,I'm sure he can better inform you on the H beam setup,as far as clearence.I have little experiance with H beams,mostly due to their weight.
The SIR is a very good rod,but you'll be pushing it to it's limits,just as I was.I never had any trouble with mine,but I may have just gotten lucky.In the piston dept.,I previously mentioned Probe Industries.They have what is called an SR Forged,that is comparable to a TRW in cost,but has oil holes instead of grooves,and as I mentioned earlier,they just look like more pains went into the machining and finishing of them.I'm running a set in my 468,but since it is yet to fire,I can't tell you with any honesty how they'll hold up.

Clearencing rods is not too tough,just time consuming.basicly it involves assembling the shortblock 1 piston at a time,and grinding the area of the rod that interferes with the camshaft,always in my experiance where the bolt is on the rod side of the large end.(I hope that makes sense,a picture would be worth a million words here).after all 8 are clearenced to at least .060,.075 would be better if you have plenty of material on your rod,then the rotating assembly can be disassembled and sent for balance.

 

so what your saying is .......

If i get the eagle SIR I beams, they will "probably" work. I believe they come with decent bolts on them by default, but there are better ones that arp has available, that I will probably use just as a margin of error.

 

The Eagle H beams use cap screws and have much more clearance at the cam than the I beams. You shouldn't have to remove any material from those rods at all, even without a small base circle cam. They do need a little more clearance at the oil pan rails though.

 

OK, cool. the oil pan rail has already been clearenced from the previous owner, so that shouldnt be a big deal.

Speaking of big deals, how big of a deal is it going to be to have the extra weight of the H beam vs the lighter I beam.

 

really not that big of a deal,since you have an aftermarket forged crank.I would never recomend using them with a stock crank of any kind.

 

I have used h beams and I beams and the h beams need more clerance. Also I am pretth sure the sir rod comes with capscrews and im positive that the scats and manley have them. The other down side to the H beams weight is you may have to add wieght to the crank when you have it balenced.But ether rod will work.

 

So, where can I find these probe pistons available for online order ?

 

Jeg's or Summit should be able to hook you up.I got mine through Motorville,but I'm not sure if they have a website.

 

I just got my rotating assembly from scat, all forged, JE pistons, one piece rear main seal. I cant stop smiling, nice quality and good to 1400hp.

 

neither jegs nor summit have a listing for the probe pistons, nor does sdpc. any other ideas ?