I know this has been talked about but I am not having much luck with the search.

The statement was made in a previous thread that there was an off the shelf 410 hypereutectic piston, but I cannot find it?


STL-H304P30 = Ford: 390, .030 in. oversize, 4.080 in. bore, 3.780 in. stroke, .080 in. dish with 4-valve reliefs, hypereutectic piston

TRW-L2291F30 = Ford: 390, .030 in. overbore, 3.78 in. stroke, 6.489 in. connecting rod, flat top, forged, piston

STL-381P30 = Ford/Lincoln/Mercury: 390, truck only, .030 in. oversize, 4.080 in. bore, 3.780 in. stroke, 6.480 in. rod length, .097 in. dish, cast piston

I know I can use the L2291 with machining to the top. If I have .10 off the top, that should result in the piston being .05 down right? (Assuming no block decking and "blueprint"
Dimensions) nothing off would give me .05 over the deck right? (Same assumptions?) Is there a head gasket that is thick enough in theory to let me run these above deck? (Big compression)

How thick is the top of this piston?

If I could get an off the shelf hypereutectic that would be fine since I do not plan to spray it. I would rather not go with plain cast.

By looking at Flatlander it looks like ROSS has an off the shelf forging for this, but there does not seem to be much faith in Flatlander.

 

Duck, sevearal of us can share your frustration with piston choices for the FE. I built my 421 ( 390 block, .060 over, 410 crank ) with the TRW L2291Fs and have about 11 to 1 compression, maybe more. I shaved .100 off the tops, am running the .041 thick felpro gaskets, and it has to have AV gas or racing fuel. Premium from the pump doesn't cut, and most of the octane booster stuff is worthless. If someone in my area sold E85, I would like to try some. Anyway, I don't think there is an off the shelf hyper available for what you want. If it were me, I think the H304P might be good after shaving the tops. You have to pay for the shave, but still cheaper than custom pistons. DO pay careful attention to what your final compression will be, or you will have, as I do, a killer engine that sits parked 99% of the time. My 2wd, with a 7.6 to 1 390, burns anything. So that is what gets driven most. DF

 

DF,

Is that the one with the 941 cam, or is it an 801 or am I confused?

That is real world information I can use too, do not want to end up in that boat. I was thinking / hoping with Alum heads and an 801 cam I might be able to tolerate a 10.5 compression ratio on pump premium. Also could probably use the large chamber ED heads to get the ratio lower. I could also bleed some compression with a 344621 (PowerMax H-296-2 replacing: CCH-296-2) although I would rather not go quite that radical and I was really hoping to reuse my 801.

I have never machined the tops of pistons before. Is there plenty of material to machine them, and on the hypereutectic will it negatively influence their strength?

I could buy 2 sets of 2291's and a set of the hypereutectic for what the ROSS and pins would cost but the crank is ~800.00 any way, so I don’t mind spending the money if I NEED to spend it.

 

Duck, the 2wd has the '801' Crane cam in it. My 4wd has a CamDynamics cam in it, with 238/248* @ 050. Both trucks have iron cylinderheads. Even with the huge CD cam in the 4wd, you don't 'bleed off' enough compression to make regular gas even a remote possibility. My pistons ( in the 421 stroker, in the 4wd ) are flattopped and have deeper valve notches cut into them. I think the CR is just above 11 to 1. The TRW forgings are plenty thick on top and I had them cut @ FPP. The shop I was working for did not yet have a piston vise. I don't know how thick the hypers are on top....you might want to ask speedpro....they are speedpros, aren't they ? I think if I were doing this now, with the knowledge from experience so far, I might look into cutting a set of L2291Fs down to 1.66 tall, but then machining a 'D' cup in them. The D-cup piston will let you maintain some good quench pad action and lower the compression a bit. What heads are you using, the early heads had a bigger D shaped combustion chamber, that might help as well. The chambers in my C8AE-Hs and D2TE-AAs are pretty small. Lastly, where do you live ? If you live anywhere that E85 is available, that might work very well.

 

Thanks for taking the time to type all this out (again?)

The STL-H304P30 are Sterling (Sealed Power/Speed Pro/Federal Mogul Performance) so yes for all practical purposes Speed Pro.

My truck (it is a 360 now) has C8AE-H heads on it, but I was planning to run Edelbrock when I build the new engine, which gives me a choice of 72 or 76cc chambers.

I live a bit south of Atlanta. I can buy AV GAS and even Racing Fuel with no real problems, but would really rather not. I haven not noticed any Alcohol blended fuel, but that does not mean I cannot get it? I usually Run Chevron or Shell.

I may order one each of these and make some measurements. I suspect that the plain cast one is actually a 410 piston. I wonder what it would cost to send it to JE and say, “Copy This.”?

 

Duck, the big chambered E-brock heads will help cut down compression some, but they are too costly for me. I can get equal performance out of iron heads, with a little effort. I can purchase racing fuel and AV gas here without any problems, but I feel that they are price gouging. E85 offers 100-105 octane value, usually for the same money as regular. But you seem to have to live near corn farmers for it to be available. DF

 

I ordered one of each of these pistons.

I will try to get some exact measurements, but here are some comparison photos. I would say the cast truck piston is a 410 piston. The Hyper is very slightly shorter than the forged, but only by about the amount of bevel in the forged one.

(I reduced these as small as they will go without destroying quality. if you get tired of waiting hit "stop". They should not take more than 30 seconds on 56.6.)








It is a shame they do not make the "truck" piston in hyper of forged.