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Old 11/29/2016, 07:53 AM   #16
p51
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Quote:
Originally Posted by robert campbell View Post
I am sensing a roller cam, aluminum heads and intake, long tube headers, and a nice big carb in your future!!

HOOOOOO BAAAAAMMM out the exhaust tips!! I have been spending my own money like a drunkin sailor!! It is way fun!!

Rob
Just FYI... yesterday (how's that for timing) they did a hydraulic flat tappet cam vs hydraulic roller cam "shootout" on MotorTrend TV. The roller cam only got between 1% and 4% better torque/hp.

https://www.youtube.com/watch?v=8VjFZMKvEwY&t=868s

I'm starting to think, the GT/CS is running so well it would be a shame to muck with the engine too much. So to get my fix I may just have to do an engine build from scratch... of course then I'll need another car to put it in

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Old 11/29/2016, 10:39 AM   #17
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Nice link and a good test. A kinda equal comparison of the two cams with nearly the same duration, which negates the true advantage of the roller cam. With me, the advantage of the roller is to be able to increase the duration which in the flat tappet world starts to decrease the vacuum and harm the idling characteristics of the engine. Making it less drivable to the owner especially with an automatic and a stock torque convertor.

The true advantage of the roller is to get far more duration, but with the steep cam lobe profile, the overlap that the intake and exhaust are both open at the same time is greatly reduced when compared to a flat tappet cam with the same duration. Better vacuum signal and better/slower idle.

Roller cams are for the owner searching for large increases in power. To achieve this you need better heads, larger carbs, and headers of some type. For the owner who is fine with the stock power, they are a waste of money.

Many people wonder how modern engines are making way more HP per cubic inch than in the past. Roller cams and other friction reducers are part of this along with fuel injection, and variable valve timing.

But a basic 289 or 302 can be changed into a fire breather with the right balance of parts these days. Boy, I live for the owners smile, the first time they put their foot in it!!

Rob
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Old 11/29/2016, 12:51 PM   #18
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Quote:
Originally Posted by robert campbell View Post
Nice link and a good test. A kinda equal comparison of the two cams with nearly the same duration, which negates the true advantage of the roller cam. With me, the advantage of the roller is to be able to increase the duration which in the flat tappet world starts to decrease the vacuum and harm the idling characteristics of the engine. Making it less drivable to the owner especially with an automatic and a stock torque convertor.

The true advantage of the roller is to get far more duration, but with the steep cam lobe profile, the overlap that the intake and exhaust are both open at the same time is greatly reduced when compared to a flat tappet cam with the same duration. Better vacuum signal and better/slower idle.

Roller cams are for the owner searching for large increases in power. To achieve this you need better heads, larger carbs, and headers of some type. For the owner who is fine with the stock power, they are a waste of money.

Many people wonder how modern engines are making way more HP per cubic inch than in the past. Roller cams and other friction reducers are part of this along with fuel injection, and variable valve timing.

But a basic 289 or 302 can be changed into a fire breather with the right balance of parts these days. Boy, I live for the owners smile, the first time they put their foot in it!!

Rob
Great explanation!

Thanks
James

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Old 11/29/2016, 03:36 PM   #19
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Of course, the stock 289 heads create such low compress they leave room for a little 'boosting'. 😜
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Old 11/29/2016, 04:39 PM   #20
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Actually the stock 289 head and the 302 4V head have some of the smallest combustion chambers of all Windsor based offerings. 56 CC for the early 289 and 53 CC for the 302 4V. But with water methanol injection "boosting" a 10 to 1 motor is no problem. Mo compression equals mo power!!

Rob
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Old 11/29/2016, 07:58 PM   #21
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The 289 from 1968 has large combustion chambers and a compression ratio of around 8.7. The 302 has much smaller chambers and higher compression of around 10.
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Old 11/30/2016, 12:15 PM   #22
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Quote:
Originally Posted by Mosesatm View Post
The 289 from 1968 has large combustion chambers and a compression ratio of around 8.7. The 302 has much smaller chambers and higher compression of around 10.
Given the discussion above, one of the concerns I would have about dropping in a roller cam into my J-code 302 engine (53cc heads, 10:1 static compression) is that with the smaller overlap and the longer allowed durations (per Rob's note) that the dynamic compression would be too high to run on pump gas without detonation...

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Old 11/30/2016, 02:01 PM   #23
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Sorry, I forgot we were discussing a 302 instead of a 289.
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Old 11/30/2016, 04:57 PM   #24
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Sorry, I forgot we were discussing a 302 instead of a 289.
No problem... I actually think we've gotten to the point where we're discussing both in general terms.

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Old 11/30/2016, 07:47 PM   #25
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Quote:
Originally Posted by p51 View Post
Given the discussion above, one of the concerns I would have about dropping in a roller cam into my J-code 302 engine (53cc heads, 10:1 static compression) is that with the smaller overlap and the longer allowed durations (per Rob's note) that the dynamic compression would be too high to run on pump gas without detonation...
You could select a roller cam that would have similar overlap to the 302 cam but far more duration and lift. You are correct in your concern of dynamic compression in your engine. Overlap bleeds off this compression at low rpm's allowing for better manners for detonation. The 53 CC chambers do require fine tuning, but I have found that with proper reduction of the vacuum advance curve solves almost all of this. But that assumes you at using a stock dizzy. If not, without vacuum advance it even becomes easier.

The real question is whether all of this is worth it? In my mind if you are not moving to higher flowing heads, long tube headers, and bigger carbs, then it is not worth it. Keep it stock and enjoy it as it is.

At one time I thought of porting the exhaust side of a stock set of J code 4V heads and install 1.94 and 1.60 valves. A sleeper motor on the outside, but again it would require headers and a big cam and increased carb to really get your bucks worth. But it could be done in my mind and make great power. I had a set of 351 C9OE casting that this was done too on my Hipo. They flowed better than a set of Edelbrock Performer RPM heads, with basic stock intake porting, but a huge amount of pocket porting in the combustion chambers and massive exhaust porting. These heads with a stock 302 J code intake and a 600 or 650 double pumper Holley would have made great power under 6,000 RPM and with a stock bottom end. The same could be done to 302 4V heads.

Rob
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Old 11/30/2016, 09:37 PM   #26
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Quote:
Originally Posted by robert campbell View Post
...The real question is whether all of this is worth it? In my mind if you are not moving to higher flowing heads, long tube headers, and bigger carbs, then it is not worth it. Keep it stock and enjoy it as it is...
Yeah, keeping my J-code stock is the way to go.

I'd like to (eventually) build an engine - just something that gets 300+hp at the wheels, nothing major. Good quality but on a budget (just for the challenge, mainly). Using the 80/20 rule - 80% of the fun for 20% of the price. The one setup I saw a few times on the web is:

Roller stock 5.0L short block bored no more than 0.030 over (if a rebuild)
Hypereutectic (or forged?) pistons
GT40 heads (good-n-cheap) or AFR 165 heads (more expensive but lighter and allow higher compression because aluminum thermals)
Weiand Stealth intake or equivalent
Tri-y headers
An "appropriate" cam for a zippy "stoplight to stoplight" street car
~9.5 static compression, ~<185psi cranking compression (as a proxy for dynamic compression)
T-5 transmission (which should handle the 300rwhp ok)
3.5 rear gear
TBI (FiTech or Sniper EFI)

One site that I found with lots of "calculators" for doing what-ifs...
http://www.wallaceracing.com/Calculators.htm

For example dynamic compression...
http://www.wallaceracing.com/dynamic-cr.php

And "Eric the car guy" is now into his engine rebuild on his Fairmont project (end of playlist)... fun to watch...
https://www.youtube.com/watch?v=L22G...U14Vt7JJ_QSZvs

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Old 12/01/2016, 09:59 AM   #27
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Hypereutectic is just fine for your build. If it was me, I would not drop below 10 to 1 on the compression. Especially with the use of an aluminum head. Size the roller to bleed some of the low speed compression off and you will run just fine on 92 crap gas we have today.

Hard to beat Ford Powertrain Applications headers for this build. They tuck up nice a tight and will work with either vintage or Borgeson power steering. I would go to the Modern Driveline hydraulic clutch system. Nice easy pedal and no worries about a cable clutch or a modified Z bar.

Here is a pic or two of the FPA headers.







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Old 12/01/2016, 12:48 PM   #28
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Rob, from the pictures I can't see how your power steering would work.

Scott Behncke
1968 GT/CS 302-4V Honors flysis income beezis onches nobis inob keesis
West Coast Classic Cougar A good source for Mustang mechanical parts too.
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Old 12/01/2016, 04:18 PM   #29
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Rob

Thanks for all the info.

James

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Old 12/01/2016, 09:03 PM   #30
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Rob, from the pictures I can't see how your power steering would work.
Scott
I did not have PS on the car at the time, but I took the pic to show that the ram connection on the frame will clear the header without utilizing the ram drop bracket that other header companies use. It clears all the hoses and the normal PS/Steering box.

rob
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