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Discussion Starter · #1 ·
i need ideas to order a custom camshaft for a 1979 304 V8 rebuild. i would like a low torque RV cam that can be used daily, will perform off road, and not consume fuel ridiculously. i will be returning to a pretty much stock compression ratio of about 8.4:1. The rebuild kit is coming from Kanter.com, if anyone has any information please let me know. Any other rebuild kit sites for comparison would also be appreciated. Scott...

Scott Reuben
1979 CJ: 304 3spd, tires, rust, miles
1989 XJ: has seen every state except Hawaii

In search of lost paths and distant locations...
 

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/wwwthreads_images/icons/smile.gif I have used the Melling RV formula as well as Crane. The Crane would be my choice. The fuel mileage will pop up just due to the cam not having the smog exhaust overlap.YUK! BARF! PUKE!/wwwthreads_images/icons/frown.gif so you will be pleased with that. We had a FS GM 3/4T 350V8 which got about 11 MPG NO MATTER WHAT WE DID. I pulled the engine down; put in a higher deck piston; installed a Crane RV cam; and the fuel mileage popped up to 15. And what a difference in POWER!!!!! Best 350 I ever sat behind......bar none./wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Tracs modified While-U-Wait by the crack moonguy/wwwthreads_images/icons/wink.gif Quadra-Trac Team./wwwthreads_images/icons/tongue.gif/wwwthreads_images/icons/smile.gif
 

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Scott

I have pretty well beat this 304 Cam selection topic to death on my own the last couple months . We have the same motor and looks like we want the same end result . I talked to quite a few local AMC engine gurus and they all recommended the Comp Cams 260H grind and use the stock AMC lifters. I liked the Edelbrock grind but there was something about the timing of the valve opening that they mentioned that wasn`t optimum(or as good as the Comp ) ( as far as they were concerned) . These guys have been building and racing AMC`s since I was a kid and they know thier stuff . Hope this helps . Good luck !

Jeff



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Discussion Starter · #4 ·
Thanks Dave and Jeff,

What happens as i approach an advertised 270 cam or above? Do i need to worry about the other specs? What will the 260 sound like? i wouldn't mind a rough idle if i would gain hp, torgue, and/or economy. Thanks for the help as always. Scott...

Scott Reuben
1979 CJ: 304 3spd, tires, rust, miles
1989 XJ: has seen every state except Hawaii

In search of lost paths and distant locations...
 

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Duration is the period of time measured in degrees of crank rotation, that the valve is open. Duration is the deciding factor to what the engine's basic RPM range will be. Lower duration cams produce the power in the lower RPM range. Larger duration cams operate at higher RPM, but you will lose bottom end power to gain top end power as the duration is increased. (For each ten degree change in the duration at .050", the power band moves up or down in RPM range by approximately 500 RPM's.)

It would have been cooler if I claimed that to be my own piece (hehe) but that is from a Cam mfger`s website and pretty much sums it up Scott. Low gears,4 barrel,more of a street orientated performance , then go with a 270 or 280 but a 304 , stick with the 260 . There is a company here in town that custom grinds cams and he said the BIGGEST mistake is people ordering to large of a cam for thier motor. You mention the idle ? Hey I used to have a COP 427 69 Chevelle and I want everything to idle like that thing did (hehe) but it aint going to happen my friend /wwwthreads_images/icons/smile.gif .

Jeff



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Discussion Starter · #6 ·
Thanks Jeff,

i will let you know how it turns out.

Scott...

Scott Reuben
1979 CJ: 304 3spd, tires, rust, miles
1989 XJ: has seen every state except Hawaii

In search of lost paths and distant locations...
 

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Discussion Starter · #7 ·
Thanks Jeff,

i will let you know how it turns out. What other specs do i need to give in order to have my custom cam ground? i'll check with the manufacturer/distributer, but let me know if you've already gone through it with yours.

Scott...

Scott...

Scott Reuben
1979 CJ: 304 3spd, tires, rust, miles
1989 XJ: has seen every state except Hawaii

In search of lost paths and distant locations...
 

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Discussion Starter · #8 ·
i saw some of the old input concerning the Edelbrock RV grind, what in particular made you decide on the Comp Cam grind?

Scott Reuben
1979 CJ: 304 3spd, tires, rust, miles
1989 XJ: has seen every state except Hawaii

In search of lost paths and distant locations...
 

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Let me stir the pot a little. I put the Comp Cams 260 in my 401 way back when. I always regretted afterwards not going with the 255 instead. Had a mild lope and 9-10 mgp depending on winter or summer with a/c running. Of course it was a tank, (Wagoneer). But I'm sure it would have had better low-end, idle and mpg with the 255. Even better yet would have been a stock replacement cam. My two current Jeep's engines were built with RV cams. The V-6 had the Edelbrock Performer cam, (which is nothing more than a copy of the old TRW EP-2 cam). Both engines had the same slight lope to the idle and less than desireable low-end and mpg. I have since replaced both engine's cams with Sealed Power, (Federal Mogul), stock replacement cams and the difference is phenomenal. Silky-smooth idle, better mpg and gobs more low-end grunt. Like comparing a tired worn-out engine to a brand new one. Now I think the other cams will develope more HP, but at an rpm that most rarely use and at the sacrifice of power in the range we all use. I will never use anything but a Sealed Power stock replacement cam for any future rebuilds unless I decide to take up racing.

Tim
'66 Jeepster Commando w/Buick 252/4.1L V-6
'70 Wagoneer w/Buick 350 V-8
'76 Wagoneer w/AMC 401 V-8 (sold)
 

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Hi Tim

Out of curiosity , what was the duration on the Sealed Power cam(s) ? I think it all gets back to what that custom cam grinder told me , don`t overcam .
Scott , DONT forget the Comp 252H grind either . It would also be very good for a stock 304 .

Jeff



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Scott

If you want , grab the file I attatched , it sorts out some cam guidelines. Pay close attention to the RPM/TORQUE ranges .

Jeff



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Unfortunately, no cam card comes with stock replacement cams. I did find a site that gave stock specs though. For the Buick 181, 196, 231 & 252 V-6's, the duration at .050" lift is 187 degrees for intake and 194 degrees for exhaust. Valve lift of .374" for intake, .384" for exhaust. For the Buick 350 V-8, 191/208 .050" duration and .387"/.403" valve lift.

Remember most all of the builders involved in racing are in tune with what works for racing, but are usually not aware of what's best for general and off-road driving that warrants low-end torque that's fully in around 2500 rpm. The manufacturers did a pretty good job of finding the best of everything for the majority of us and did quite a bit of r&d to come up with it.

Tim
'66 Jeepster Commando w/Buick 252/4.1L V-6
'70 Wagoneer w/Buick 350 V-8
'76 Wagoneer w/AMC 401 V-8 (sold)
 
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Hey I dont know if they have this at the marine shops around you guys for the AMC motors...but I use a marine cam...they cost more due to the fact that they patented from Mercruiser, etc...but they starting RPM in these cams is about 500 RPMs! and top out about 4500-5000 RPMS...they are the real stump pulling-axle snappin'-tire smokin'-driveshaft twisting motor mount 'popin' bumpsticks...I even told my tow truck friend about them and Ive gotten two free tows from him he was so happy(both times snapping the model 20 axles=5 total...HEHE)...just my thought and insight

MARK (OIIIIO) LANGMOTORSPORTS
1977/CJ7/GLASSTUB/460CIFORD/C6AUTO/4"LIFT/33'S
 

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The other side of the equation, is how each cam manufacturer measures there cam. Numbers mean little between different manufacturers due to various methods of measuring. They should be good for comparing one manufactures offerings. To maximize HP, try to optimize lift.

Enjoying Montana's Big Sky & Snow(Skiing that is)
 

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I tend to ignore top HP figures in lieu of comparing torque figures. Even if the torque of one engine is greater than another, the other might have more usable power due to what the torque is on each motor at a normal operating range of 2500 rpm and below. Low-end grunt is the usable power that I look for since I don't race, mud-bog or sand drag.

Tim
'66 Jeepster Commando w/Buick 252/4.1L V-6
'70 Wagoneer w/Buick 350 V-8
'76 Wagoneer w/AMC 401 V-8 (sold)
 
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