73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: Rib Tickler on January 11, 2009, 06:55:47 pm
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Hey guys so I`m looking at throwing an RV cam, intake, Headers, and dual exhaust with an "H" pipe and possibly a set of roller rockers into my 1979 1 ton dually. the motor is stock at 35000 kms and I need more grunt for pulling a trailer daily. it`s a work truck so it needs to be reliable. my parts guy tells me he thinks there are three stages of rv cams, I`m thinking of going with the stage 3 for the most power, I`ll find out on moday about price and availabilty.
Thanks in advance.
Ron
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check out a slew of cams at www.summitracing.com
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A lot of what makes the horsepower depends on what you have. What heads, engine, intake. Since you are swapping the intake, it depneds on the heads you have and compression rtio of the engine. The roller rockers in my opinion arent going to make enough difference to justify the cost of them. At least not for your application. The most restrictive parts are the intake and the exhaust, which you are addressing, cam wise, on a small block a 268H Compcam? is what I have run and have been really happy. Save your money on the rockers and invest that towards a good carberator, unless you already have one. Replace the clutch type fan with a flex fan, or just go with electric fans. What engine does it have?
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it`s got the original motor for the truck, and 35000 are the original kms. just a rough horse power increase is what I`m after. 190, 200, 210, or maybe even 220 hp?
I don`t want to put new heads on I`m just looking to up the hp for towing.
Thanks,
Ron
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what engine? I thought I saw what it was in another post, but cant find it. 350,400, 454?? 300hp total isnt impossible or hard, but not 300 more hp
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350
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It would be hard to estimate without specifics but 200hp would be a reasonable guess.
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Ignition advance curves of stock GM HEI's of that era sucked
Once you decide on which parts to install, and get em on the engine
you may want to think about giving this guy a call
He will send you an HEI advance kit curved to your vehicle specifications
if you have no clue what you are doing with an HEI
it's well worth the $50
(http://image.highperformancepontiac.com/f/10860536/hppp_0708_14_z+hei+hei_curve_kit.jpg)
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Price the stock gM roller rockers at summit as well. They aint all that expensive.
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OK this is gonna be long and I apologize. Forget about the roller rockers you don't need them. Forget about horsepower you want torque. Horsepower is a calculation of torque over time in fact they are always the exact same on every motor at 5250 rpms. No truck in the world is gonna benefit from horsepower except a NASCAR truck and they ain't gonna tow. You want torque building parts like a dual plane manifold, small tube headers, a 600 cfm carb, a good ignition system and a cam to match all these. Instead of the roller rockers upgrade your ignition system you'll be happy you did cuz after all, these parts are worthless if the gas isn't getting burned to begin with. Also never pick out your own cam. Call the cam manufacturer and give them all your specs like engine size, vehicle weight, carb size, manifold type, exhaust type, overall gear ratio, tire size, type of tranny, is it a stock converter if auto if not what is the stall speed, intended use of the vehicle, operating rpm range, compression ratio and type of fuel are some of the questions they will ask you. Then they will be able to give you options and give you approximate hp or torque with each option. First things first get your ignition system upgraded with one of those proform complete kits that come with the coil and the module along with curve kit, vacuum advance can, cap and rotor. Then add the small tube headers on. Play with the mechanical advance till you get it dialed in. Then get a nice small 4 barrel like a 600 cfm Holley. After all that you may find you don't need a cam at all. Just so you know your compression ratio is probably around 8.5:1 and that 350 is making around 185hp bone stock. With the upgrades I suggest before a cam swap you will probably be making more like 225-250hp with similar torque numbers. Then add a cam and you can probably expect another 25-50hp assuming you don't over cam. To make anymore power you are going to need to either increase compression ratio or add a blower or nos. I hope this helps and is not confusing you instead.
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Thanks guys.
thats the kind of info I was looking for Russ...thanks.