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#21
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What is the intake centerline of the installed cam? That will answer your question.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#22
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When you talk about advancing the cam X degrees are you decreeing it or just putting in 2-4-6-8 degree keys? Murf |
#23
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Going with a typical timing chain and gear.....when the "dots" point to eachother is where MOST refer to as "straight up". That is all wonderful and fine but without actually degree'ing in the camshaft that is a MOOT conversation. You either degree it in and know or you pot shot it and guess?
Will it run? YES. Will advancing 4 degrees from WHERE IT USED TO BE bring the power band lower in the RPM? Who knows as you do not really know where it was. If it was already in at 106 and you move it 4 degrees --> 102 degrees CL....probably going to LOSE power EVERYWHERE but yes it will run. Last edited by Stuart; 08-28-2021 at 09:37 AM. |
#24
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Another tid bit to consider. If one is going by a cam companies printed material with the description of a "power range" or "RPM operating range" it's generic information.
Too many variables involved.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE Last edited by Stuart; 08-28-2021 at 09:37 AM. |
#25
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FWIW, I hope you took time to degree the cam in when using the advance keys on the multi key time set. That 8 degree crank multi key compcams timing set is marked for it’s reference from the cam timing. Using the 8 key the advance is meant to move the intake center line from 113 to 105…. A full 8 degrees, not 4.
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#26
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In a stock application think about why the factory never installed a 041 or a smaller 744 in a 428 or 455. Think about RPM limits and those cams usefulness.
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#27
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Not 100% sure but believe the only place where the 390 hp engine was used was in the 428 Grand Prix.
The Grand Prix was a real boat and a great number of them were NEVER raced at the track. No need for the cam to be bigger than the 068 camshaft for that application. Installing the 428 engine/parts in a A-Body vehicle or F-Bird, is another story, imo. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#28
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I have a 428 and an 041 cam.
I only used the 041 cam because I had it for years, just sitting there. I race with it and it's pretty much a dog the last 1/8 mile of the 1/4 mile run, 5000-5700 rpm. The 60ft is great, 1.65 seconds. Degree it and Install it at 109 Last edited by Stuart; 08-28-2021 at 09:04 AM. |
#29
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Here is what I found on the net and if this is the only way the 041 cam can be manufactured then here we go : 308/320 231/240 366 hp/5500 rpm 445 lb ft /3900 rpm OL 87 LSA 13.5 IC 112 Last edited by Stuart; 08-28-2021 at 09:17 AM. |
#30
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This is a stock motor and ran perfect with the last cam and also with this 041 cam. The only reason I am even thinking of moving the power band toward the launch is that I thought I could. I am thinking of putting the gear back on the original setting with no advance. If some one thinks I can benefit some by moving 2 degrees at the crank for a one degree advance at the cam please advise so. Whoever said to go back to the original cam has the best idea yet, that was my original thought, however since I all ready have this 041 cam installed should I be maybe getting the Rhoads variable lifters and 1.6:1 rockers like others do . Going back to the former cam is going backward toward a smaller cam. What do I do to get better performance out of the 041 cam that is in the car now. I have new Johnson lifters in the motor now and HD Chromemolly push rods and 7/16" screw in HD rocker studs from Butler. What advantage can I gain with Rhoads Variable Lifters in my street driven vehicle anyway? I don"t want to waste money. Back in the day Royal Pontiac would shim under the valve springs and use Distributor curve kits and copper head gaskets etc... I do have the air induction Ram air pan with foam seal under the Tri power carbs. and cool air is just what this engine loves. I Installed a Trans Am Scoop near the windshield for working air induction on the 1976 formula hood.at one time I took the snorkels out to let air in to carbs and to cool off the headers but I don't have to do that any more. I brought down the engine temperature in other ways. Last edited by Stuart; 08-28-2021 at 09:20 AM. |
#31
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Last edited by Stuart; 08-28-2021 at 09:24 AM. |
#32
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Last edited by Stuart; 08-28-2021 at 09:26 AM. |
#33
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Lets say I Install the 041 cam with the dots both on 12 o'clock - "straight-up". Since the 041 cam is installed now, I will consider options on improvements that will gain some performance if there are any to be had. Maybe some day I will go back to the former cam but not now. The question now is if I were to install the 1.6:1 rockers, with inexpensive rollers on them and maybe Rhoads variable lifters, what would be the performance gains on street use, if any? Engine specs are thus: 376 hp factory, guess by me is as much as 428 hp with real air induction adds 35 hp plus headers and dual exhaust. I upgraded to the 041 cam already. It's never been dyno'd. It has a TH400 transmission with a B&M shift kit, Gear Vendors over under drive, and Herb Adams suspension all around with Koni shocks for handling. vFour wheel Disc Brakes and Posi-Traction. Lowered by two inches and race suspension. There are 3.23 gears in the rear end. At about 3000 rpm I run 80 mph in overdrive. Last edited by Stuart; 08-28-2021 at 09:32 AM. |
#34
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Without knowing what heads, stock or ported, compression ratio, I think you may be expecting too much performance from the 041 cam. The changes you want to make to move power around is probably only going to give less power everywhere. The 041 cam is not the cam to look at those drag race charts about moving the ICL to change the power band rpm. If you are not going to degree it, install it dot to dot.
Using 1.65 ratio rockers to add more lift is a good way to increase power, especially with the small lift the 041 has. Then you will need to check the roller tip pattern on your valves and purchase the proper length pushrods. As mentioned in your other thread with the same title, I use the 041 cam, but it down on power compared to my old cam that had less duration and more lift. |
#35
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Pontiac P/Hwy, and G/P 1969 You are correct about the 068 in a stock bottom end configuration. |
#36
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Last edited by Stuart; 08-28-2021 at 09:34 AM. |
#37
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Last edited by Stuart; 08-28-2021 at 09:38 AM. |
#38
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The 744 was never in a 455 or a 428. What was in the 73-74 SD "only" was the 493323 cam which specs out the same as the 744. But the 323 cam has a special small gear to accommodate the large distributor gear. |
#39
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I think you had the right idea with the 4 degrees of advance for your set up. Use the +4 advance key instead of the +8.
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#40
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TRADER MIKE 2012, you are saying that you feel that the 041 cam is larger than you like. If this is true, then you do not want to install higher ratio rockers because that will make the cam feel slightly larger and the opposite way you are saying you want to go. 1.65 Ratio rockers increase lift 10% and marginally increases duration. I'd say about another 4° but that is subject to discussion. Regardless, if you are thinking you want a smaller cam then you don't want to go with higher ratio rockers.
It's been years since we burned up a bunch of dyno time moving around the ICL, but every time we moved the ICL either advanced or retarded the net result was usually a loss of overall power. If we advanced the cam we would pick up 5 horsepower down low but loose 20 up on top. Reverse the procedure and retard the cam and pick up some on top and loose even more down on the bottom. We finally had to admit that the cam manufacturers actually knew what they were doing when they set their specs.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. Last edited by lust4speed; 08-25-2021 at 03:41 AM. |
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