Coalbucket

421 stroker in 4x4 pickup. I have stock 317's now and am debating on smaller combustion chambers and if it's a good idea to go for ported heads?

KCS

iTrader: (20)

What compression ratio are you wanting? Porting would probably be a good idea, stock heads are pretty small for a 421ci engine.

JoeNova

421 stroker?

LS3 top end, maybe get the heads milled for more compression.
If you're only worried about torque and not power, then cathedral ports are probably the way to go.

pantera_efi

iTrader: (1)

Hi, most likely you may have a 12:1 CR now.

Head c/c and gasket thickness ?

Lance

Coalbucket

I am looking for 10.5:1 -11:1. Going to be running on pump gas. And yes main focus is mid range torque. 2000-5800rpm or something in the range. Going with a Yank 3200 stall lock up converter and TSP recommended the Torquer V2 on a 110 LSA. It has -23cc dished pistons and with the 317's and .040 gaskets the compression is 9.8:1 according the machinist. Would a thicker gasket say .050 be drivable with the 243's?

JoeNova

Drivable? Why wouldn't it be driveable?
Why not use the thinner gasket with the 243s?

Why not get something better than stock castings? You've spent the money on a big cube setup, why choke it?

Coalbucket

I meant if the comp was 12:1 and staying with pump gas. Sorry should been more specific. I want to open it up as much as possible and keep cathedral port heads for the torque. Was looking into A.I. 232cc full cnc 243's. Is there a head out there that would better suite my application that you would suggest?

Coalbucket

Also adding the FAST LSXRT intake with a 102mm

Darth_V8r

iTrader: (4)

If you're willing to spend some money to not be restricted by the heads, call Tony Mamo.

Coalbucket

Will do thank you

JakeFusion

iTrader: (7)

I'd call Brian Tooley up and get some TFS 225 heads. I'd stay away from square port if you want to make torque. But the TFS heads have properly sized runners and valves to optimize the 4" bore of your 421 to get the torque way up. The 235 or 245 would make more power but possibly at the expensive of torque down low. And they would have issues getting to the right CR as you'll see in a moment. Tony Mamo has some sportsman heads that are 223cc based on the TFS castings. So they may be another option as well.

Also, compression is your friend on an NA setup. 9.8:1 is garbage. You can run more than that on a supercharged motor in these engines. I'd shoot for 11:1 or higher depending on the final cam selected.

And I think a 232/234 110 cam would be an interesting choice for a stump puller. It would like right around 11:1 CR in that motor as well. Only problem is, you have to get to a 56cc chamber with .040" gaskets to get to 11:1. So you'd either have to mill stock heads or the TFS heads down a bit to get there. But it's not an insane amount but still quite a bit of milling. Those pistons are not great.

AI could also weld up chambers or you cold move to the 5.3L castings and have them ported by TSP or AI. But they don't flow enough for the 421. Even the 225 will be choking it out, but it will make a ton of torque below 5500. Or you could mill to 59cc and have something in the 10.8:1 range. You have to look at calculated DCR. And with the 232/234 110... the IVC would be 68.5 degrees at .006" lift. Factoring in the 4.03" bore, 4.125" stroke, -23 dish pistons, .040" gasket, -.006" out of the hole pistons, and 58cc chambers, you'd end up with 10.8:1 and a DCR of about 8.4:1. Which would work fine on 91+ pump gas.

Actually, that'd be a fun motor to drive on the street. People have done TFS 215s and AFR 205s on 408s with larger cams and the HP/torque is impressive. Usually in the 500/500 range with a lot of torque early. But with the added stroke in your motor and the smaller camshaft with the tighter LSA, I'd go with a slightly larger head to build even more peak torque.

NAVYBLUE210

Best heads for your goals IMO with LSXRT Intake...
MMS 235s out of the box for 6000 RPM and less,
Have the Intake Ported by Tony as well.

Darth_V8r

iTrader: (4)

I was thinking the same but with 421 ci a 245/250 sized runner would still build torque.

But you and I both know, the heads won't hold him back, which was really what I read into his goals.

1lejohn

iTrader: (9)

We just finished a 408 build in an 04 2500 HD 4x4. We are going with the 317's , and the stock intake for now. The cam is a 226 @ .598 and 111*. This thread has me thinking about a better head now, but it is a big heavy truck. I am going to do an intake , maybe the T.B.S.S.
The 102 is the best intake but the drive by wire T. bodies cost big $ . I hope to have it dyno tuned by next month. If the 170K tranny lasts !! I'll post the figures. Circle D has a nice convertor for the 4l80's. Good luck with your build. Some good info in this thread.

Darth_V8r

iTrader: (4)

If you're building for torque, a set of used AFR 205's would be bonerific. Honestly, a set of aftermarket 220cc heads on a 408 would make massive torque.

Coalbucket

I called Tony Mamo yesterday and he recommended a set of 235's with a 52cc combustion chamber and a custom cam from him specific to his heads on this build. Said his 235's can flow 345cfm. Priced me on assembled heads and a lifter kit once I get them all I have to do is bolt them on.

Do you think Circle-D makes a better converter than Yank? I have 160K on stock 4L80 as well and so far has held up wonderfully. Well see how it does after I get it back together this time. Also going with Flex lite fan and shroud set up and in the near future I'm sure a larger trans cooler too.

Coalbucket

Also any recommendations for what oil would be best to run? Live in Ohio and will be driving it year round. STD bearing size as well.

I've heard good things about royal purple and Best line oil additive as well. And suggestions?

PowellSixO

iTrader: (1)

I've had good luck with Amsoil. I run this in my truck.


http://www.amsoil.com/shop/by-produc...?code=aslqt-ea

Coalbucket

Alight thanks

1lejohn

iTrader: (9)

Those heads would be nice. I've never run aftermarket heads on any of my builds. I like circle D , but I'm biased I live in the Houston TX area. They have great service, and build awesome transmissions. My stock 317's have a little work done to them. They got a valve job , new Manley valves and surface milled for trueness. The work was done by Houston Engine and balancing. I talked to a local tranny shop and he stated the 80E's were good for 200K . We will see! He said about 2400 to repair it. Ouch! there goes my upgrades.