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258 cam specs??

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Ollie View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ollie Quote  Post ReplyReply Direct Link To This Post Posted: Oct/15/2018 at 8:59am

I found this info:

 

Isky 133125

Best torque & economy in passenger cars & trucks. Max compr., 9.5:1, smooth idle, std axle ratio, good vacuum, computer compatible. Std. to 600 CFM Carb. RPM-Range (1500-4800) Valve Lift (.450 .450) Valve Lash hot (.000 .000) ADV. Duration (256 256) .05 D

 

Isky 133126

Low/mid-range performance cam. 9.5:1 compr. 3.08-3.70 axle ratio. Passenger cars & trucks. Up to 625 CFM Carb. RPM-Range (2000-5500) Valve Lift (.445 .445) Valve Lash hot (.000 .000) ADV. Duration (262 262) .05 Duration (208 208) LC 109

 

I have a Isky 133125 in my 232. Running a Eldelbrock 500, Pertronic ignition,  2;73 gears, 727 trans. I never had the engine in the American before rebuild so I cannot compare performance before and after. It idles smooth, has fantastic vacuum, so much so it whistles at times, consistently gets 22mpg highway and smooth performance thru out the rpm range. At 70 mph I am turning 1850 rpm.

 

I spoke with Uncle John a lot before the 232 build and told him I wanted a driver. He recommended this cam. He was also a Isky man and used nothing but.  I had a lot of respect for his opinion.

 

My 258 build will be a hwy driver also. Plan on the same set up, Eldelbrock 500, 2:73 gears, but it will have a 904 w/lockup torque converter and HEI dizzy.  Not sure what the rpm will be at 70 mph but thinking about 1550 or so.

 

I don’t want any surprises or issues on this build. I am about 99.9% sure I am sticking with the Isky 133125 cam. It has been a winner and non-issue for me.  

Having AMC Fun,

Ollie


1966 American Convertible -- "The Rambler"..SOLD
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1989 Jeep Comanche Pioneer, 4.0L, auto, 2wd
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 5spdwagon Quote  Post ReplyReply Direct Link To This Post Posted: Oct/15/2018 at 6:26pm
I have a few ideas I am kicking around in my head.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amxron Quote  Post ReplyReply Direct Link To This Post Posted: Oct/15/2018 at 8:18pm
1550 is too low for cruise with a carb only FI can pull that off.
You will be lugging the engine and need more throttle opening to maintain speed.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlin1945 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/15/2018 at 9:42pm
If anybody is interested I have a Lunati cam and lifters I bought for my NHRA stocker back a ways ago. Lunati screwed up and sent me this one and wouldn't take it back. It was put in the engine and broken in but obviously not what I needed. I have the matched lifters in order in the box for it.The specs are for stock lift (.400/.400) duration longer than stock (.212/.212) with 108 c/l at 4 deg. advanced. The cam and lifters are in mint condition. I can send pics of the cam, lifters and cam card to your e mail or phone. I want $150 + shipping. I haven't been able to post pics for a while , can't post pics.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Oct/15/2018 at 11:12pm
Originally posted by FSJunkie FSJunkie wrote:

The 1 barrel carbureted 232 and 258 use a shorter duration cam (SAE 259*, or 185* @ .050). Melling's part number for this cam is the SRC-6.

The 2 barrel carbureted 258 uses a longer duration cam (SAE 262*, or 190* @ .050). Melling's part number for this cam is the SRC-8.


wow, good info. i wasn't aware there were different grinds from the factory. and good eye catching that in your build!

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Oct/16/2018 at 7:00am
The 133125 is the 256 Supercam. If you want a near stock cam that's the ticket. The 262 is the next step "up"and is a great choice for a noticeable bump in performance without sacrificing economy. Note the rear axle recommendations and rpm range. You can still run a stock axle, the engine will just need to run 100-200 more rpm to start off, so you will likely take a small hit on city mileage, but make up for it cruising.

I have found that most engines really like to cruise at 2000+ rpm. With that 262 cam I'd say 2200 would be a good target. You want to be in the power band of the cam. Most stock cams "start" around 1700-1800 rpm, so you want to aim for a couple hundred over that. There are some exceptions in newer vehicles where they do cruise at around 1700 rpm -- those cams come in earlier and top out earlier.

Note that the two Isky cams mentioned have a power band of 2500-3000 rpm. That's about it for ANY cam. That's why you need more gear for a high rpm racing cam -- it doesn't produce good torque until higher in the rpm range. Typically high rpm means a big HP number, but for street use you need to forget that and go for a good torque number at lower rpm. Torque is power and felt more than HP. Build for a good low torque rpm and flat torque curve for great street power and you will feel it, even if the HP numbers are a bit lacking.
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ollie Quote  Post ReplyReply Direct Link To This Post Posted: Oct/16/2018 at 5:49pm
Thanks Frank, good info.

I just decoded my 92 Ford Ranger truck rear end. It is 3:45. It fits perfect with the 133126 Isky.

The Ford Ranger is a 5 speed std. The last truck that i used in the convertible was 3:73, AOD auto, which i changed out to 2:73. 

Now i am not to sure what to do. Open to suggestions. 

Having AMC Fun,
Ollie
1966 American Convertible -- "The Rambler"..SOLD
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 5spdwagon Quote  Post ReplyReply Direct Link To This Post Posted: Oct/16/2018 at 7:36pm
You going to use the rear from the truck? Did you use a 8.8 rear in your convertible?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ollie Quote  Post ReplyReply Direct Link To This Post Posted: Oct/16/2018 at 9:12pm
Originally posted by 5spdwagon 5spdwagon wrote:

You going to use the rear from the truck? Did you use a 8.8 rear in your convertible?

It's actually a Ford 7.5" Ranger pick-up 1989-1993. Yes thats whats in my convertible. I changed it to a 2:73 gear. 

Having AMC Fun,
Ollie
1966 American Convertible -- "The Rambler"..SOLD
1974 Postal Jeep -- "Rapid Delivery"...SOLD
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Oct/17/2018 at 6:48am
As I think I said, I have a 3.55 rear gear in my 63 Classic wagon with AW4 (early model with 0.70 OD). It's fine, but a tad less would be better for highway mileage. A think 3.31 would be the sweet spot -- reduce in town mileage and take-off slightly but increase highway mileage 1-2 mpg, and increase comfortable cruising speed (runs ~65 @ 2100, the Renix computer - and I think the Chrysler HO computer also - starts to enrichen the fuel mixture about 2500 rpm, which is ~78 mph, and mileage goes down noticeably). I typically keep it down to no more than 2400 rpm, which is right at 75 mph. The 3.45 wouldn't do much (67 @ 2100, 80 @ 2500 -- my tires and trans), but would help a little.

Depends on the OD ratio though. The AOD has a 0.67 OD. With my setup that equates to 68 mph @ 2100 rpm, 81 @ 2500. Bear in mind you want to run around 1900-2000 rpm to be in the torque band and have power to cruise up hills without downshifting or losing much speed, so lowest cruise speed with the AOD and 3.45 gears would be 63.6 @ 1900. You could pull off 60, but rpm would drop to 1800. When I dropped my 4.6L to 1800 cruise (3.08 gears though) it would pull it without struggling, but was working harder and gas mileage went down.  If I'd had abetter torque cam (was just a bit over stock, about like the 256 Supercam) it might have pulled it off, but with the 3.08 gears I was running 72 @ 2000, ~65@1800. There were places with a 60-65 speed limit that I didn't want to run over, and it was really too many rpm in 3rd gear (only 50 @ 2000, 60@2400 -- the top of economical cruise) for me to be comfortable.
Frank Swygert
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