I think we've had a failure to communicate here. It's the exhaust valve
sizes that I quoted as smaller. If there is a difference in intake ports, I
have not noticed it.
My intent was to point out that the conventional wisdom amongst the muscle
car folk that 915 heads have the larger exhaust valves seems to be in error,
if my cars are any example. They all have the 2.08" intake valves, as far
as I can determine. I have not measured port sizes.
The off the line snap that I noted as superior was as compared to the 68s
and 69 that I have owned. I have not noted a difference in response to the
67s, as my low mileage 67 was quite sick due to having sat without running
since 1976 (in about two weeks, I'll have it totally back to standard and
factory fresh, and when I get it re-installed, I'll be able to make a fair
comparison.) As for my other 67, it is a convertible, so I don't think the
comparison is fair, although I do notice a much better throttle response as
compared to my 68. This could be due to the AFB as compared to the AVS.
The difference in displacement between the 413 and the 440 is due entirely
to a bore change, they are both 3.75" stroke engines, thus the low speed
torque is probably not much affected by the displacement change as it would
be if it were due to a longer stroke in the larger engine.
There is a difference in compression ratio, and in head casting number
between 67 and 68. The 68's use the 906 head, which does have the 1.74"
exhaust valves. Most of the literature seems to be repeating that the 67's
had the 1.74" exhaust valves, but as often happens in the hobby press, this
appears to be an error that has been propagated from source to source. My
source is my own micrometer!
I'm not aware of any difference between 66 and 67 440s as used in Imperials,
but as noted, there is a difference in the heads starting in 68.
I notice that some speedway rules don't permit use of the 915 heads in
"hobby-stock" - for example take a look at:
http://www.yakimaspeedway.com/2001/rules/yakima_hobbystock.html
Dick Benjamin
----- Original Message -----
From: D. Dardalis <dardal@xxxxxxxxxxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Wednesday, July 10, 2002 11:47 AM
Subject: Re: IML: 413 vs 440!
> Please see inserted responses...
>
> At 08:07 AM 7/10/2002 -0700, you wrote:
> >All 3 had an off-the-line snap that none of my 68's or my 69 showed.
>
> That could be due to the smaller intake ports. However, it may be tough
to
> compensate for the 6% lower displacement. Another possibility could be
due
> to smaller primary chokes of the 413 carburetor (if indeed they were
> smaller). However Dick, your claim of better off line launch is not
> supported by the literature. Look at the 64 road test (in the '64 year by
> year. 0-30 was at least a second slower from the 67's 3.4 seconds (can't
> access the site right now).
>
> >My two 67's do seem to have better throttle response, so perhaps you are
> >right about the earlier 440s.
> >
> >In my case, my 67s have 915 heads, which is the vaunted closed chamber
head
> >the muscle car guys are always carrying on about, so perhaps that is
where
> >the difference lies. The 68s have 906 heads.
> >
> >By the way, in case anyone cares, the exhaust valves in the 915 heads are
> >1.6", not 1.74" as given by the gurus on the MOPAR web sites.
>
> Actually, I believe the 67 440s had the larger intake ports like later
> engines. So, I was referring to the 66 model year 440s only, that could
> have the same off line response characteristics to 413's (if the carbs
were
> the same).. The fact that the intake ports were redesigned for the 67
> model year seems to be supported by contemporary literature. See:
> http://imperialclub.com/yearbyyear/1967/CarLife/page4.JPG
> where they discuss the larger intake ports on the figure caption. In
> another 67 model year article of car life, they are also talking about
1.74
> exhaust valves for the 67 model year. This was for the HP engine, but I
> think they used the same heads on all 440s. To the best of my knowledge,
> the differences between 67 and 68 heads were very minor, and only related
> to emissions. Performance-wise, the two heads were similar. Am I wrong?
>
> D^2
>
>
>
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