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By DiLL - 6 Years Ago
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Hello all! New to the forum and assembling my first automobile engine ever.
I currently have:
.60 over 292
ECZ-G heads 1.92" I 1.6" E rocker arms are 1.43's
9425-B intake manifold converted into a dual plane
600 cfm carb
Engine and flywheel have been balanced
the cam im looking at is 239/253 @.50 107 LSA my lift at the valves would be .466/.458 (its a comp cams mutha thumpr)
My compression ratio (according to an app i downloaded) is about 9.8
I drive about 80 miles a day on the interstate (75-80mph). I really just want to do some "spirited driving" on the way to work everyday. Do you guys think this cam would be a wise choice or should i go with somthing smaller? Also, what kind of power/torque might i expect from this setup?
I have a 61 unibody that it will be going into with the original 4 speed (for now)
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By charliemccraney - 6 Years Ago
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Welcome to the site.
The 9425-B intake is dual plane from the factory. What did you do to it?
The cam will be a bad choice for a street engine. The Mutha thumpr is a bad choice in general because it is all about the sound so you are going to sacrifice power for sound and that is on top of the really big duration @.050"numbers which make it a bad choice for the street by themselves. There are plenty of well designed cams that will give you a performance sound, along with the performance. Mummert is a good source, www.ford-y-block.com. Isky cams is another. The best option is always to call your favorite cam grinder, answer their questions realistically and honestly and take what they give you.
Unless you have domed pistons, your compression is not 9.8:1. It will be about 9:1 at best, which will really be too low for a cam like that. That is another reason not to use it.
I think a more appropriate cam would be something with low to mid 230s @ .050" at the most. Even with a cam like that, don't plan to use the truck as a truck. You will be able to do light duty stuff but it will not have the low end to haul or tow like it was originally intended. Once the engine is built save for an aftermarket aluminum intake and higher ratio rocker arms as these will help you much more, for street performance, than a bigger cam. Dual exhaust of some kind, will also be needed. Headers are best but rams horns are an excellent choice for oem appearance.
If the heads have not been ported, then the most you can hope for is about 300hp.
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By DiLL - 6 Years Ago
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Thanks for the heads up! So, perhaps the 280-I-07 (228@ .50) 107 sep would best suit my needs with what I’ve currently got? And I had my intake manifold converted from a four barrel to a two barrel. I’m under the impression that doing so could help with torque/response? I also have no plans on hauling anything with it, I just liked the truck. but, had read that the unibody design (when heavy loads where applied) caused twisting/bending in the body and the doors wouldn’t shut properly. Is this true?
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By charliemccraney - 6 Years Ago
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A 4 barrel is usually better for torque, response, and fuel mileage. Use a vacuum secondary 4 barrel, and most of the time you will be driving on a small 2 barrel and when the engine demands it, the other two open up. Do not use a mechanical secondary carb for the street.
You said you are using a 600cfm carb. Isn't that a 4 barrel? I'm not aware of a 2 barrel that size.
The 280 cam will be a much better choice. You will need to ensure that you have the necessary valve guide and piston clearance for the lift of the cam, particularly if you will look for high ratio rockers in the future.
I have a uni and I have had it loaded down with about 1000 lbs in the bed, 1 complete Y-block, the automatic transmission, and an engine hoist.. Even with all of the rusty mounts, the doors opened and closed fine. I have heard that same claim, though.
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By charliemccraney - 6 Years Ago
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Here's a thread about a similar type of build using one of the 280 cams. That's about the best you can do without porting or getting a set of aluminum heads.
http://forums.y-blocksforever.com/Topic110858-1.aspx
Here's a youtube video of it running so you can get an idea of the sound.
https://www.youtube.com/watch?v=XnBND0X0OTo
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By Ted - 6 Years Ago
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See if this link gives you a rough idea although it’s a smaller camshaft grind. It’s a 0.070 over 292 with a 228/238 camshaft, ECZ-B 4V intake, and a Summit carburetor. The major nuance on this engine build are the metric rings as they are typically worth 20-25HP on the Y builds.
http://www.eatonbalancing.com/2015/05/01/unported-iron-heads-can-still-make-over-a-hp-to-the-cubic-inch/
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By PF Arcand - 6 Years Ago
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Ted; The cam you selected may be the best choice, but for the moment, referring back to Dill's 2nd choice the 280-107, that cam from Mummert, is also available with a 111 LSA. Would that have worked better than the 107 in a truck ? The reason I'm asking is that I believe that's the grind he used for one of his poster engines, the 337" one that posted 393 HP at 5400 rpm & 420 lbs ft of torque ..
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By charliemccraney - 6 Years Ago
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Dill,
Take note of how the manifold was modified in Ted's example. You want to do that. While a mill makes that job much easier, you can do it at home with a die grinder or even a dremel. You also have a lot of room under the hood and 2" of spacers, along with a 14 x 3 air cleaner should fit. Another thing that helps to smooth airflow into the carburetor bump up cfm slightly is a K&N stub stack. Sometimes they require slight modification, for choke linkage, or casting variances between carburetors but they are proven to work and not a gimmick. Spacers and the stub stack are things you can try later, if you don't have the money now but the intake should be prepared properly from the start.
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By Dave V - 6 Years Ago
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Charlie: Does that manifold modification hurt low end torque any? Dave V
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By Ted - 6 Years Ago
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PF Arcand (2/7/2018)
Ted; The cam you selected may be the best choice, but for the moment, referring back to Dill's 2nd choice the 280-107, that cam from Mummert, is also available with a 111 LSA. Would that have worked better than the 107 in a truck ? The reason I'm asking is that I believe that's the grind he used for one of his poster engines, the 337" one that posted 393 HP at 5400 rpm & 420 lbs ft of torque ..
To be accurate, more information on the engine combination above is needed. 9.8:1 compression ratio is tough to get on a 292 without either milling the heads very heavily and/or using domed pistons. Head gaskets are also a player.
In regards to the question regarding the 107 versus 111 degree lobe centers, the 107 cam would be more peakish in its performance and definitely more rumpy sounding at idle. The 107 cam would also have more low end grunt than the 111 camshaft. While the 111 degree lobe center camshaft would be a bit more sluggish at the bottom of the rpm curve, the manifold vacuum at idle would be better by about 1½”Hg. The 111 camshaft would also top out at a higher rpm. Here are the DCR numbers for each cam with everything being equal except the lobe centerlines.
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By Ted - 6 Years Ago
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Dave V (2/7/2018)
.......Does that manifold modification hurt low end torque any? Dave V
No.
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By PF Arcand - 6 Years Ago
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Interesting stuff on the cam specs. Thanks Ted..
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