350 Aluminum heads!

Hey who pissed in your cornflakes? I have owned SBB and BBB and I do know the difference. Every engine has its merits. If you're a torquemonger and don't mind 8 mpg, then sure grab yourself a big mouthful of BBB fat boner down the throat and never turn back. Not everyone wants or needs it.

You think these 350 guys in here are just fawning over their engines without knowing what torque is? No one's ever driven a BBB and still wants a 350? Surely it cannot be! Go take your asinine comments elsewhere.


G

 

Yeah, just ignore him... He likes to bash the SBB but thats ok... He prefers to mess with an engine that has a terrible design and weak block but whatever LOL.

 

Maybe the guy never ran up against a 350 with a big shot of nitrous. :Brow:

Wouldn't that 350 just kick total *** with the Alum heads SP intake and some nitrous!

Remember guys, there are a lot of 455's out there that have the Alum heads on their cars and just run the DP intake, A B4B more than likely. Not all guys with a Street 455 run a SP intake they run the DP intake so that is why I think the heads should be first.

 

Thanks for the support Sean. I notice he's got a picture of one of those aluminum blocks as his avatar icon. The BBB is so much better of an engine that it needed a whole new redesign on everything made out of aluminum. It's amazing at just how many people who claim to be knowledgeable try to insult those with different educated and experienced opinions simply because they disagree.

It's one thing to bash the SBB with an ignorant opinion, it's quite another to start it all off by calling me a liar, saying I've never experienced a BBB when I have posts all over this forum about them, with me talking about the ones I used to have. To be fair, maybe he doesn't read much and is a knuckledragging mouth-breather and simply reads a few comments and then dives toward the comment button and spews forth whatever his short term memory could muster, but I'm probably wrong about that.

The 455 is simply an afterthought to the 400/430, with cylinder walls so thin you have to sonic test EVERY block to make sure it'll be worth building any hotter than stock, and you better be praying for a small miracle when you have to bore it. I'll trade durability and longevity over a ticking time bomb with more power any day.

This is also why I'd rather have a 400/430 if I was going big, and I'd build it pretty conservatively.

I'm an easy goin person, and I try to like everyone I meet. I enjoy coming here to these forums and collaberating, helping, and learning. I'll even forgive people and move on. I also won't take scheie from anyone either. That's just how I roll. You gotta have an open mind about other's viewpoints and be willing to admit mistakes inside yourself, unlearn, relearn. It's not so hard. :TU: (just sayin in general, ya know)


G

---------- Post added at 12:48 PM ---------- Previous post was at 12:34 PM ----------

The heads make the most sense because there's already an effective intake for the 350 that'll be a pretty hot combination with some free-flowing aluminum heads, and would increase the sales of those intakes! You'd only want to go single plane if you were going pretty radical, and that targets a smaller crowd.

Being able to run higher compression with existing combos, aluminum will just be awesome. Even mild-moderate builds could benefit from these heads, not just higher end, so it targets pretty much the entire 350 community.


G

---------- Post added at 12:49 PM ---------- Previous post was at 12:48 PM ----------

The TA dual plane intake outflows the stock heads! so yeah, x3

 

A quick comment about being able to run another point of compression with aluminum heads; there seems to be some misunderstanding going on here.

Realize this is not any kind of advantage or gain to be had. The reason you want to run another point if possible with aluminum is because the heat leaves the combustion chamber more quickly, which is a power loss. This is also the reason the heads will tolerate the additional point without detonating when an iron head may not. In short, to get the power back from the quicker heat loss, run another point (or so) of static compression ratio when switching to aluminum heads. OR, thermal barrier coat the chamber and leave the compression ratio alone.

Devon

 

Ok, ok. I'm cool.

---------- Post added at 01:31 PM ---------- Previous post was at 01:17 PM ----------

Well what I'm seeing here is that the 350 is handling RPM and boosted power ratings much better than the 455, so what does that tell you? Aftermarket parts aside, the end result is HP and TQ and RPM and gives a clear indication as to what the block can handle without having to put a steel-belted jock strap on it (the girdle/halo). When the 350 gets to power ratings that require said jock strap, it will be in excess of what the 455 is capable of (not power wise, but durability wise). Some of the fastest Buicks out there are running boosted v6's (that take many engineering cues from the 350) with less than 300 cubes, so CID isn't always the answer--just the CHEAPEST answer per HP/TQ for milder builds.

As far as mild-moderate street builds, any engine is safe within those parameters, and if you want the easy way to make power, the big block makes more sense, sure. I totally agree--I swapped my 350 for 455's for this very reason many years ago.

---------- Post added at 01:40 PM ---------- Previous post was at 01:31 PM ----------

So this brings up an interesting issue: is the power loss from faster heat dissipation EQUAL to the power gained from adding compression?

The compression increase is between .5 and .75 points to equal it theoretically, yet you can add more than that and still be within the safe, non-detonation zone. This means the heads will make more power compression wise on the same grade of fuel--then there's the head flow and runner design and valve placement to consider as far as it gaining more power. Am I wrong here? If so, I will gladly concede and reconfigure my mental files.


G

 

If you think of it from a very basic thermodynamics point of view, for a given engine piston/chamber/cylinder design and fuel grade/mixture/cylinder fill, it will detonate at some heat amount X. It doesn't matter how you stay under X to avoid detonation, either with more compression ratio to compensate for fast heat loss or less compression ratio and barrier coating for slow heat loss, or any combination of factors. The idea is that you have to stay under the threshold of self-ignition/detonation while trying to get as close to it as you can. There isn't anything magic about aluminum or any other material that allows you to go above X without detonating. Once the heat is high enough for self-ignition, the fire is going to light all by itself.

Devon

 

Ok I get it. Thanks for clearing that up for me.

I was going to add more comments about this issue, but the more I thought about it, the more it made sense. There is no 'increased compression beyond detonation factor x' meaning they would be equal in this regard.


G

 

Not to stray too far off topic, but in a related anecdote, I was able to get away from the detonation demon by switching to aluminum heads. My compression ratio was high due to having to mill the iron heads more than I would have liked, so I was always fighting with rich jetting and less-than-ideal ignition timing. The switch to aluminum with the same chamber volume allowed me to lean it out a little and increase total advance to get things back into a more "ideal" state. Where 10.8:1 was too much with iron heads, it's now much happier on 93 octane!

Devon

 

That cracks me up when you talk about the block girdle,and call it a "jock strap":laugh:.

I think a more accurate description would be a hernia truss though,to try and hold the internal parts in,that the strength of the block can't.:laugh::laugh:

http://www.dmesupplygroup.com/orthopedics-hernia-trusses.html

 

So you're saying that because less people have done it with 350's than with 455's, the information isn't as valid? Theories aside, it HAS been done, so proves that it's fully capable. More will be known once more people have documented it, sure. It's impossible to tell exactly what will happen in the future, but if what we've seen so far is any indicator, the outlook is pretty damn good. If you were a wagering man, you'd be safe to put some money down on this. The more radical you go with an engine, the more gamble you take, period. I think with the 350 your odds are better for it to hold up past points where the 455 is currently limited.

Even so, all this aside, there's much more to it than simply 'what makes more power and at what cost'. Plenty of people want 350's, even those who've had big blocks before--not because of the power obviously, but for other reasons, such as versatility, longevity, and economy; and let's not forget other factors, such as every day driving, handling characteristics, power to weight ratio, etc. Not everyone wants a car that's only good to be driven 1/4 at a time or has so much torque it costs a fortune to get it to hook up and then adversely affects other aspects of the car.

It seems to me that BBB lovers are coming in here because they're curious as to how well the 350 will actually do, as if they're considering changing to it once others have done all the work and spent the money on results, so they'll feel safer swapping if they find out the boosted 350 makes more power than the boosted 455 because of block durability issues.

This is of course on the extreme end of the spectrum. Most people won't really be doing all this and won't choose a 350 over a big block because of this--but each engine has its merits based on what the individual wants/needs, and the 350 has a solid niche in the community. It's just a damn shame it hasn't been recognized so much in the past as it is now because of forced induction, because it really is a great overall performer, even N/A.

Anyway...heads first!


G


Edit: I forgot to mention that the boosted 350 I'm thinking of (can't remember names, my appologies) pulled 1021 HP and 808 TQ and 8's in the 1/4 revving to 7,500 RPM! I think boost was 20 lbs. This is from memory and though it's usually pretty good, I may be off. The info on it I found here on these forums somewhere a while back.

To be fair, there was some indication that it needed some kind of girdle after tearing it back down and examining the mains, but this is waaaay more than the 455 could do without a girdle. 600 hp and 6,000 RPM is supposed to be the threshold for 455's before a girdle is needed.


G

 

lol

---------- Post added at 03:13 PM ---------- Previous post was at 03:07 PM ----------

OK, ok. Didn't you tell me to calm down earlier? :laugh:

I'm with ya here broh.

It's still in the early stages. The initial results are quite exciting, and show great promise.


G

 

to get back on topic.. somewhat..
the n/a build I think this would help the most would be the stoker builds; 370 or 373 sbb .100 extra stroke with .060-.075 overbore thats the tits right there:laugh:

 

Sweet, no foreplay, I can dig that. lmao

---------- Post added at 03:26 PM ---------- Previous post was at 03:21 PM ----------

What's the limits on stroke for the 350? May eventually see aftermarket steel cranks if the 350 popularity soars up high enough.


G

 

i wouldn't hold my breath on aftermarket cranks but i know who will do a billet crank for me, 2 other members were also going different routes but never got a definite price comparison from their routes to mine.

with a honda 1.889 b earing you can offsett grind an extra .100 stroke and yeild 3.95..someone mdentioned if you used 1.85 bearings you could possiblty go 4inch stroke