[Scarebird]

Originally Posted by 69birdboy

...crappy 411NP pistons (like 14cc valve reliefs and way down in the hole, they are awful)...

Why not fix the issue you identified first and see what results?

[Brent Flynn]

It makes no sense to put a good set of heads on a "crappy" set of pistons if you're gonna run it hard... I bet i could do a 400 with TRW's, a set of 16's with new valves and springs, guides and a good valve grind... find the right cam, use a stock intake and i think i would outrun the alum head/cast piston setup.... or run right with it, and i bet my shortblock wouldnt have a huge hole in it after 100 passes shifting at 5800-6000rpms... my point is, its not that expensive to have a good valve grind/new valves/springs done to a set of 16's... you dont need portwork.... also, its not that expensive to build a trw shortblock... I guarantee you if you did that, and had a proper tune on it, it would run in the 12's easily with the gears and everything else you have, as long as you have traction.... i would rather sacrifice a few HP and have a reliable bottom end than have a set of heads you cant even really see the potential in because of your rpm capabilities... not tryin to ruffle any feathers, but, you have a ticking time bomb, unless you gonna shift below 5000 rpms... thus never seeing the benefit of a better flowing set of heads... JMO.... You're gonna lose alot of low end with 260cfm intake ports on a 400...even with 10 to 1 compression

[jimmy daniel]

Originally Posted by Tim john

69 Birdboy,

Bret has offered you some very wise options, give them plenty of consideration. He has boat loads of experience and is only looking out for your best interest.

Tim john---

I agree. He goes fast with stock stuff.

[Brent Flynn]

Hey Jimmy... yeah, it just seems like some are not lookin at the obvious...
If he's just gonna cruise it, you dont need alum heads... if he's gonna run it hard at all, you need better parts in the shortblock... IF he really wants aluminum heads, he would be much better off building a good shortblock and adding the heads at a later date... easy to make 400 hp with stock 16's/62's on a good flat top piston up to the top of the deck, balanced well and good ring seal, as long as the shop that does the valve grind knows whats happenin..... 750cfm carb and the right cam for the application, and good headers are about all you need to get it done... and some good tuning!

[screamingchief]

FYI: A set of TRW/FM 400 forgings are gonna be damn near as far down in the hole as his current pistons are (.020" down minimum for the forgings).

So that move really gets him little to nothing without also zero decking it.

The only significant difference there is the 8cc or so valve relief difference due to the cast pistons being the 8 valve relief items with the bevel.

And another thing is that pistons in general dont "make" more or less hp.

But better heads sure can make more hp.

As I understood this,the OP's whole line of thought here was to leave the shortblock together & in the car,and I'm not about to try and convince him it's the right or wrong path to take here,that's his choice and I respect that choice,thus I gave what I thought was the best advice for the situation as he had described it.

And I know I dont necessarily feel a cast bottom end is a ticking timebomb either really,JD ran his cast 8 relief bottom end pretty dang hard,and it lived,hell we all used to run cast bottom ends and most all of them took the merciless abuse in stride,did some of those fail,yep they sure did,but a whole lotta them lived long abuse filled lives too.

The OP clearly stated that he's commited to keeping the current bottom end for the time being regardless of whatever his head choice ends up being.

If ya'll wanna brow beat him into doing a full on rebuild here,by all means be my guest,I'll just let the fella make up his own mind,as I generally dont take part in that sorta thing.

I dunno about all of you out there,but those of us on super tight budgets just cant afford to spend money twice,so from time to time temporary compromises get made,and any risk associated with that short term choice gets taken into conisderation as well,but in the end you do what you gotta do.

Lets look at some of the basic parts costs for those #16 heads:
16 Ferrea SS. Valves = $200.00
Crower #68404-16 Valve Springs = $130.00
Valve Stem seals = $20.00
Crower #87048-16 Steel 7° Retainers = $65.00
Crower #86107-16 "Machined" 7° Valve Stem locks = $50.00

So that's $365.00 in parts right there,add new guides and the machine work for those and a "good" valve job and then add a bit more to surface the heads,and machine the guide bosses for good seals,yadda,yadda,yadda and there is no way he'll have those #16 heads "done right" for less than $500.00,honestly it probably will end up closer to $750.00 - $800.00 or so in my experience,and that's with ZERO porting,and any additonal porting would put the cost for his iron heads @ well over a grand for sure.

Anyone that says otherwise is either cutting corners on the parts being used,or the machine work costs,or is likely BS'ing you about some other item.

I know this,right now I got a set of well ported #96 heads on my all cast 455 bottom end,and back when I had those heads done (before the aftermarket aluminum heads became commonplace items) they cost me then as much as a set of KRE-D's would cost me today,so I know for sure that were I making that same sorta decision today,the choice would absolutely be a no-brainer.

Back when I had those #96 heads done it was $200.00 for the "good" valvejob and like $300.00 for the guides and hardened seats (parts included in that price),then add surfacing the heads for $50.00 and cut the guides for PC seals and slot for 1.65 rockers add another $75.00.

So labor for those heads were what,$625.00.
And that does'nt even include the porting or blocking the exhaust cross-overs.
That work added like another $800.00 in one fell swoop.

Here's what my #96 heads parts costs were:
Valves = $240.00
Crower #68405-16 springs = $80.00
Retainer & Keepers = $85.00
Spring shims = $33.00
Freeze plugs = $5.00
Heater hose fitting = $20.00

So that's what,another $463.00.

So if one really wants to dump a bunch of cash into some iron heads,you betcha it's easy enough to do that,especially if your naive enough to think otherwise.

Have I had iron heads done for less,yeah sure have,back when I kept the crap OE valves and just had the guides "knurled" and did the bare minimum needed to get them back together,re-used OE retainers,used the cheap "stamped" valve locks instead of the good "machined" valve locks,but even then the heads were almost always over $500.00 with "good" valve springs and such.

Recently I just had a set of FE 390 heads done awhile back for my brothers '68 Ranchero GT,nothing special done at all,basic valve job,surface the decks,fresh guides,had to get new valves,retainers,locks,springs,and those heads were over $800.00 out the door and again nothing special was really done to them.

So it does'nt really matter much what anyone here thinks it'll cost to get those #16 iron heads fixed,what really matters is what they guy your dealing with at the machine shop tells you it's gonna cost to get them fixed.

And again be fore-warned,dont dare assume your gonna "get off" cheap on a project like this,you should always assume it's gonna cost more than what you expect it to cost,as it almost always will cost more than what you thought it was gonna cost.

FWIW

Bret P.

[screamingchief]

Originally Posted by Brent Flynn

Hey Jimmy... yeah, it just seems like some are not lookin at the obvious...

The obvious point here is that the OP clearly stated in post #3 that the shortblock was not going to be torn into at this point in time.

That should be the end of any conversation on that topic.

Even if some of us feel it's a wise idea or not,it's his choice and you gotta respect that.

So that means were left with the discussion/debate about the heads.

Hence my comments and recommendations.

There is always more than one way to reach the same basic detination

2¢

Bret P.

[Brent Flynn]

I agree with you on pretty much everything you are sayin', but a cast piston will not stay in there near as long as a forged... ive got pistons(forged TRWs) in both my race cars from 1983 and 1985... very reliable pistons... i wouldnt even think to run a cast piston as hard as i do the forged ones... the rods dont bother me near as much as the pistons do.... i just hate to see him spend 2k on a set of alum heads, then, decide to run it up to 5600-5800 to get it to run, and have a piston failure and tear up the heads... it just seems that you'd want to invest in the rotating parts first if you are plannin on runnin it very hard on a regular basis... I just makin recommedations based on my experience... none of this stuff is cheap... you just got to decide what scares you and what doesnt... i wouldnt think that the cast pistons would hold up under the kind of horsepower that the alum heads have the potential to make... again, im not arguing, just stating my opinion

[screamingchief]

I hear you,,,they are flip sides of the same coin...

I've never seen a "true" cast piston failure tear up a head half as bad as a "popped" valve head will do,and that's especially true with a forged piston.

When you pop a head off one of those OE 2 pc. intake valves,it will typically imbed itself in the top of the "stronger" forged piston and just hammer the dog $#!t outta the head,and trust me it's not a pretty sight.

If that happens with a cast piston,then the piston typically shatters on impact and all the parts end up in the crankcase in short order and the head damage is far less severe.

So new valves are really not optional here no matter what heads get used.
And that's mandatory no matter what short block is under the chosen heads.

Typical "true" cast piston failures mostly involve cracking/breaking the skirts of the piston or breaking the ring lands,and rarely do those sorta cast piston failures ever result in any serious head damage or such,the only time that might damage a head is if the top ring land failed,and as such it broke loose into the chamber,but even then the head damage is minimal,as the piston material is aluminum,and thus it's much softer than the iron head is.

Most of the time when you see a fully scattered "cast" bottom end,99% of the time it was the cast rod that let loose first,and any cast piston failures were mostly collateral damage as the pistons were just an innocent bystander in all that resultant carnage.

Cast pistons usually dont cause those sorta failures,typically it's something else that's to blame.

Dont get me wrong,I prefer forged stuff too,but it's not always an item that's open for consideration,often it's use what you got or dont use it @ all,then what good is it doing?

FWIW

Bret P.

[Brent Flynn]

oh yeah... ive had valve decide to make 2 pieces instead of one...and i was travelling down the highway at 65mph when it happened... tore the sheet out of the cylinder and made shrapnel out of the cast piston that was in there... i wont use stock 2 pc valves in a new engine, whatsoever... No matter what he decides, i hope he has the best of luck with it... nothin worse than bad luck with these things...