906 or 452 which is best overall

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OUTLAW

OUTLAW

Master of All Mopars
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I have been cleaning out my garage and storage sheds and pitching just about everything but mopar parts. I came across a complete 69 383 out of a roadrunner and a complete 74 440 out of a ????. The 383 looks like it had a million miles on it. But the 440 looks like it was just rebuilt. Bearings look new, cross hatch in cylinders look fresh, top of pistons were clean.
In another shed I found 2 sets of heads complete, one set are 906's and the other are 452's.

Now for my question, which are the better heads stone stock and which are the better heads ported? Also which heads came off which motor? I know there are a lot of variables but just a general opinion is what I am looking for.
 
I think the 906 edges out the 452, but not by much at all.
 
the 906 came off the 383. 452 heads have hardened exhaust seats
 
RRR as usual no clue 452 castings are the same as 906 except 452s have hardened seats no brainer from there.
 
CudaJunction said:
RRR as usual no clue 452 castings are the same as 906 except 452s have hardened seats no brainer from there.
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I got my information straight from Jim Laroy (IQ52). Where'd you get yours?
 
CudaJunction said:
RRR as usual no clue 452 castings are the same as 906 except 452s have hardened seats no brainer from there.
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Wrong. If you look into the intake ports of a 906, they are obviously different than a 452. The guide boss and the shortside are quite a bit different. Compare the two side by side and it is very clear. As far as what's better, it depends. In stock form the 906 is a little better. http://www.hotrod.com/how-to/engine/5115-cylinder-heads/ http://www.moparts.org/Tech/Archive/bb/62.html
 
I will stick with the 452s Thanks. OK whats cheaper to rebuild. If I have to build stocko heads from the beginning I will take 915 castings.
 
CudaJunction said:
My mind been building these cars for 20 plus years. DONE
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20 years that's it! Since 1995!!!

The reality is set up with the same valves, springs, and same VJ. There probably about about the same ET wise if you ran them head to head. And the hardend seat thing goes out the window once the new seat is cut, you would need to actually press in a new seat.
 
CudaJunction said:
My mind been building these cars for 20 plus years. DONE
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A legend in his own mind....


Junction: There's no need to insult Rusty. Everybody has an opinion, state yours and move on... Arguing is not helping the original poster.

I've met rusty and seen his posts, he knows SOMETHING... Most of his recommendations are accurate...
 
I believe there is more variance from casting to casting than casting number to casting # when talking these heads.
I have no bench to prove this. Old school aproach kind of opinion here. I do know some carving under the seat and a back cut valve has always been what woke up a iron head big block for me. More so than a simple casting # swap. I dont believe you would feel a gain without this extra effort. I never put a stock head on anything that I have plans of running at even a slightly higher rpm. It doesn't take a max effort thousand hours of testing on a port to get real and noticable gains. Some quick cutting in the most restrictive areas and I have been just as satisfied as when I spent a stupid amount of time on them making them look pretty like seen in the head porting tutorials. Waisted effort in my experience but I'm no pro.
I have broke thru to water after running a few thermo cycles before so you do have to be careful in a couple spots. This is why I have my opinion about casting to casting. Some have more room for porting than others of the same casting #. This luck of the draw can be very disappointing. Pull the head and start over with another.
Depending on the piston I usually will start with a 906 or 915 just because they are considered the muscle car heads.
I think that it doesn't really matter the casting # as they all have plenty of potential and it never make sense to bolt any of them on without taking advantage of this nearly cost free
horsepower even on a stock rebuild. That's my take on these iron castings. Unless your engine needs the max wedge port size or the weight loss of an aluminum casting they
can get the job done very well. My first set I built back in 79 or 80 was a eye opener for me even with the stock valves.
 
OUTLAW said:
I have been cleaning out my garage and storage sheds and pitching just about everything but mopar parts. I came across a complete 69 383 out of a roadrunner and a complete 74 440 out of a ????. The 383 looks like it had a million miles on it. But the 440 looks like it was just rebuilt. Bearings look new, cross hatch in cylinders look fresh, top of pistons were clean.
In another shed I found 2 sets of heads complete, one set are 906's and the other are 452's.

Now for my question, which are the better heads stone stock and which are the better heads ported? Also which heads came off which motor? I know there are a lot of variables but just a general opinion is what I am looking for.
Click to expand...

906 heads came on just about every RB motor from 68-72, until the 452 was introduced in the cast crank 73 and up era! Of course there were other variations such as the 346 and 250 heads, but all were pretty much the same!

As for building motors and all this chest pumping, it doesn't take 20 plus years of building motors to answer tech questions such as this, just a little common knowledge!! RRR is very good at answering most any question without all the drama, which apparently Cuda Junction must live for! This isnt a contest, just answering a general knowledge question, why bring personal conflict into this???

On a side note, before you trash that 69 383 motor, there's a member of the Mopar swap meet FB page that lives in Ohio looking for an E383HP block, might want to check yours before you trash it! Geof
 
CudaJunction said:
You n him have something to learn in the mopar world................
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Pretty bold statement to make when you don't know anything about us.

Him and I can school you in Mopar, we've been doing it much longer than you, and combined, we have more experience than you most likely will live...

Do you have any tech "articles" in the How-to section yet???

Count how many him and I have and see if you can match us. And I have a few more coming in the future....

How come you don't have as many "thanked" as he and I do??? That's a good indicator of how many people that you've helped on this forum...


He's one of the few people that I would TRUST to work on MY car...

Rusty is a great guy, and in fact traveled almost one hour to help me load up a car that I picked up from another member near him and towed home. Without his help I would have had much more trouble getting it started and loaded on my trailer.

He helped me and used his truck to take me to the parts store and get parts and load the car. He did this all on his own and didn't ask for anything in return. He's the kind of guy that I like to keep around me and call a friend, it's hard to find good people like that today, he's there when you need him... :prayer:

And as his friend, I don't appreciate you trashing and insulting him when he hasn't provoked you. :ncool:


As I stated in my previous post here, the purpose of this site is to help others, not bad mouth and sling insults at people that are trying to help. Stay on point, only post information relevant to the thread, or keep it to yourself and move on...

Good day... :D
 
krazykuda said:
pretty bold statement to make when you don't know anything about us.

Him and i can school you in mopar, we've been doing it much longer than you, and combined, we have more experience than you most likely will live...

Do you have any tech "articles" in the how-to section yet???

Count how many him and i have and see if you can match us. And i have a few more coming in the future....


He's one of the few people that i would trust to work on my car... I couldn't say the same for you....

Rusty is a great guy, and in fact traveled almost one hour to help me load up a car that i picked up from another member near him and towed home. Without his help i would have had much more trouble getting it started and loaded on my trailer.

He helped me and used his truck to take me to the parts store and get parts and load the car. He did this all on his own and didn't ask for anything in return. He's the kind of guy that i like to keep around me and call a friend, it's hard to find good people like that today, he's there when you need him... :prayer:


As i stated in my previous post here, the purpose of this site is to help others, not bad mouth and sling insults at people that are trying to help. Stay on point, only post information relevant to the thread, or keep it to yourself and move on...

Good day... :d
Click to expand...

this ^^^^^^^
 
Well said krazykuda, RRR is one of our best tech's here and everyone should read into what he takes the time to wright...
 
OUTLAW said:
I have been cleaning out my garage and storage sheds and pitching just about everything but mopar parts. I came across a complete 69 383 out of a roadrunner and a complete 74 440 out of a ????. The 383 looks like it had a million miles on it. But the 440 looks like it was just rebuilt. Bearings look new, cross hatch in cylinders look fresh, top of pistons were clean.
In another shed I found 2 sets of heads complete, one set are 906's and the other are 452's.

Now for my question, which are the better heads stone stock and which are the better heads ported? Also which heads came off which motor? I know there are a lot of variables but just a general opinion is what I am looking for.
Click to expand...

906 heads came on 383-440 engines from 1968-1970. 452 heads came out in 1976 on the 400-440 engines.

"stone stock" they are pretty much the same and variables in casting might give one or the other a slight edge at any time. Generally on our bench the 906 has a slight edge, 3-5 cfm at various lifts but not all lifts. Really for all practical purposes, call 'em even.

Ported is an entirely different matter. The 452 is a little easier to port for the beginner and get some flow increase. For all out the 906 is the best of the two. The 452 will top out about 305-310 cfm and the 906 has been made to flow 340+ cfm here in our shop.

Should it make any difference, I have been working on the factory iron heads with my dad since 1959 when I was 11 years old. See November 1959 Hot Rod magazine, HOT PROSPECTS PLYMOUTH'S NEW 361---The engine they said wouldn't run.
 
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