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Old 02-25-2004, 12:22 AM
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comp 1.7 rockers for 351W

i'm looking at some 1450-16 (summit part # cca-1450-16) or some 1431-16 (summit part # cca-1431-16)

the rockers were suggested to me buy a guy i really trust, but don't like to bother all the time with questions, but i usually do anyway

motor is a basically stock 1974 351W, intake and carb are the extent of mods so far, headers to be installed.

i don't see coil bind happening since lift won't be increased that much (6.25%) going with the 1.7 over the 1.6 which would still be an improvement from the stamped ones.

74 heads have press in studs, and use a positive stop system and provide no means of adjustment. Will these allow for adjustability and will they work with the heads unmodified? (do i have to drill out pushrod holes or something strange)

These are rail type rocker arms, and are not to be used with guideplates.

So all in all, i'm just wanting to make sure there arn't any unforseen problems using either of the 2 comp magnum rockers

And would these work on a set of pro topline or world heads??

Thanks a bunch guys and gals
Dubz

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Old 02-25-2004, 05:26 AM
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Thumbs down

I personally don't see why you would want to go this route as it is not giving you anything for the money spent. I would save my ducketts and upgrade to a later E7TE or GT-40 head and camshaft upgrade (should come by cheap if used).

When using higher lift rockers, you will not know as to whether you will experience coil bind or pushrod rubbing until setup and the valvetrain geometry has been corrected.

Just my opinion.
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Old 02-25-2004, 12:52 PM
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I have been told coil bind won't happen even with a .500" cam so with the stock cam probably being alot less than 95% of that i'm sure i'll be fine for binding

And what do you meen nothing for the money spent? i'll get a faster profile, and more lift (even with the 1.6 because they are so much more ridged than the stock ones). wouldn't that be worth a few hp??
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Old 02-25-2004, 01:58 PM
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Quote:
Originally posted by Dubz


I have been told coil bind won't happen even with a .500" cam so with the stock cam probably being alot less than 95% of that i'm sure i'll be fine for binding

And what do you meen nothing for the money spent? i'll get a faster profile, and more lift (even with the 1.6 because they are so much more ridged than the stock ones). wouldn't that be worth a few hp??
Like I previously said,
Quote:
Just my opinion.
You do what you feel will be best for your interests...
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Old 02-25-2004, 02:01 PM
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Originally posted by KULTULZ
Like I previously said,

You do what you feel will be best for your interests...
well i was curious to know why you felt that way is why i asked
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Old 02-26-2004, 10:35 PM
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bump for more opinions
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Old 02-27-2004, 01:54 AM
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Unhappy

Well...Here is my feeling on it.

It is a 1974 TORINO (heavy) that is powered by a smogged 351W. The CR and valve timing are not conducive to high output. You have stated that you added an intake and carb (which is a good first step) and are thinking of headers.

To me at this point, money would be better spent on a cam/valvetrain upgrade. Maybe a stiffer rear for street performance. Just recurving the distributor (is this points or DURASPARK?) will give you better results.

What you are attempting should not even be considered until you have one on the ragged edge and are looking for any type of power increase. Merely opening the valves further on your present application is not going to help street performance.

Now that's my opinion only and it has been known to vary...(and be wrong)
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Old 02-27-2004, 02:24 AM
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Quote:
Originally posted by KULTULZ
Well...Here is my feeling on it.

It is a 1974 TORINO (heavy) that is powered by a smogged 351W. The CR and valve timing are not conducive to high output. You have stated that you added an intake and carb (which is a good first step) and are thinking of headers.

To me at this point, money would be better spent on a cam/valvetrain upgrade. Maybe a stiffer rear for street performance. Just recurving the distributor (is this points or DURASPARK?) will give you better results.

What you are attempting should not even be considered until you have one on the ragged edge and are looking for any type of power increase. Merely opening the valves further on your present application is not going to help street performance.

Now that's my opinion only and it has been known to vary...(and be wrong)
allright, well my good long post got eaten

plan was for hooker competition ceramic coated, and recurving dissy(duraspark) when car got back out of storage (as i just got carb and intake on before having to put it away) Rear end is getting the full treatment of shocks, springs, tubular control arms, and gears.

wouldn't higher lift rockers would be the same as running a larger cam (since the at 0.050" duration would be longer as well as more lift). I thought it would be, which is why i was considering this. Same gain as a mild cam only from removing the valve covers. For street i thought the rule was most lift with small duration.

Heads will be coming off next winter and getting ported and milled and a cam will probably be put in at that time too (looking at a comp 270H cam kit)

if it won't give me any gain by swapping the rockers there is really no point. but i was under the impression it would
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Last edited by Dubz; 02-27-2004 at 02:39 AM.
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Old 02-27-2004, 06:18 AM
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I don't like press in rocker studs, they may not hold up and end up coming out. IMO- your wasting your money on a set of rocker arms for press in studs. Also with out guild plates they must be the rail rocker arms. You can pick up another set of 351w heads on e-bay next to nothing, then you can do screw in studs, little port work, valves and VJ, now you have a set of heads that would handle a good cam.

Ben
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Old 02-27-2004, 06:32 AM
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Quote:
wouldn't higher lift rockers would be the same as running a larger cam (since the at 0.050" duration would be longer as well as more lift).
Duration will not be increased, only lift. The reason for increased lift is better flow, and you need the cam and ports for that.

Look around and find a set of E7TE, GT-40/GT-40P heads to modify and you will be ahead of the game when you upgrade the valvetrain.
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Old 02-27-2004, 11:20 AM
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thanks for the info guys
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Old 02-28-2004, 10:58 AM
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I am in a similar situation as yourself.


I took a look at a few simulated combos, and with a stock camshaft in a stock 351w, using a performer intake and 600 cfm carb, the higher ratio rockers improved the hp, about 500-1000 rpm after it peaked. Needless to say the gain was so minimal, if you didn't look close at the graph you wouldn't know it happened. So you can imagine I would not recommend them.



I did notice two things, by going with a stock cam, the previously mentioned components and gt-40p heads the hp and tq looked like this



The pic probably won't show up, what it shows is a 50hp increase at 4000 with head swap only and a 48 hp increase with the 268 cam only, and the tq increased in both cases more so by 5lbft with the heads only. combined heads and cam, the hp jumped by 100 at 4000, and the hp and tq kept improving over the stock rpm curve, at one point between 6-7000rpm the hp increases by 150, not that the motor would last long or make it there.

The first set of lines (top to bottom) are stock cam and gt-40p heads, the middle one is stock cam//heads, the last one is stock heads and comp cams XE268H. Needless to say the cam is sitting next to my computer and I have a set of gt-40p heads that I am in negotiations to purchase. On another graph with the gt-40p and 268 cam combined, the hp jumped another 50 hp at 4000 rpm and the tq jumped slightly. This combo would give you a few things positive, this cam in another engine made 15 hg of vacuum, 17 hg with a stock camshaft is considered good, so 15 ina performance cam that will give you a bit of lope, that is great. the low end torque remains or increased over stock, and the hp increases substantially, sounds like a winnner, I will hopefully find out, I do know that a lot of people with mild 351w's seem to like the 268 grind 35-242-3. Also should point out that the above graphs and combos were figured with 8.5:1 compression, the heads should in reality, put it into the 9's (depending on pistons, I was thinking stock 87 model) so you should expect a bit more hp and tq. Something to think about


357ford

Last edited by 357ford; 02-28-2004 at 11:25 AM.
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Old 02-28-2004, 12:48 PM
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Arrow

I see the photos are in Yahoo and of course they won't let us peons access them. Can you post the photos on this board's photo section and then you can post them here? I would like to see them.

Of course you guys know the GT-40P heads require a special header flange, right?

Raising lift in this fashion is usually done with full competition engines usually, say a corner cylinder that is starving for fuel due to intake design or whatever.
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Old 02-28-2004, 01:59 PM
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Here is the stock cam vs stock cam and higher ratio rockers

http://f1.pg.photos.yahoo.com/ph/kjm...&.dnm=94df.jpg


Here is the stock cam and heads vs. stock cam and gt-40p heads vs. 268 cam and stock heads.

http://f1.pg.photos.yahoo.com/ph/kjm...&.dnm=ca2d.jpg

I didn't wanna go through the mess of reposting the pix, but they are just a click away.


YOUr right you do need special headers to gain access to the plugs, but some have had success installing other headers, there is a shorter plug you can purchase, original to the mountaineer, some cases it does require the header to be removed in order to change plugs, but they make reusable gaskets, and time is free, haha.


357ford
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Old 02-28-2004, 05:05 PM
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Question

Quote:
there is a shorter plug you can purchase, original to the mountaineer,
Is this a MOTORCRAFT or ACCELL plug? If FORD, I did not know that!

Thanx for reposting the graphs!
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