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Old 09-21-2013, 11:05 AM
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Camshaft Suggestions

Boy I know camshafts there's only a million inputs needed to make a decent suggestion, then a million different brands and grinds.

Basic engine is a Gen 1 350. I would love to set it up for a roller but the machine shop says gonna cost ya $700'ish I've never had one done so I honestly haven't any idea.

Pickup will be street driven. I'm way past trying to impress anyone with a huge cam pat. Sure would be nice to have some serious low end torque.

Expected C/R will be 9.1 to 9.3

Presently has a set of headers honestly don't what they are.

I have a performer intake with a Holley now.

For trans I'm installing a 700R4 I'm not sure if I will upgrade the rear gears I have 3.50's in it now considering 3.73.

I forgot to mention I have 902 Vortec heads. They are in very good condition and haven't been hogged on. I look to clean up the ports and runners. No real hogging just smoothing things up a bit.

I have a HEI distributor and I intend to set it up where everybody's home at 3,000.

I'm looking at a Hyd Comp cam CL -210 -2

Lobe separation at 110 218 duration at .050 .454 lift.

I have seen some references to RV cams I have not researched that but I'm wondering if this is close.

Appreciate any info.

Dan

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Old 09-21-2013, 11:15 AM
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700? buy a roller cam or dont,your choice.
changing from 3.5 to 3.73 is a very small change,not worth the money,,,buy the roller cam instead
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Old 09-21-2013, 11:29 AM
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A flat tappet cam would suit your needs just fine.
However if you want to go roller on the cheap then ditch the block you got and get a 880 Casting Vortec block, these came with factory roller cams, so you can reuse the GM roller lifters so it's done on the cheap.
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Old 09-21-2013, 12:59 PM
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Most stock camshafts are ground to produce lotsa low end torque for pulling heavy loads and trailers. . If you want good low end torque, keep your stock camshaft and leave the rear end ratio as is. Torquing camshafts typically have less thanb 218 degrees duration and less than 35 degrees valve overlap. The advantage of a roller cam is that you will have faster valve acceleration rates off the seats for quicker cylinder filling and more low end torque. A high lift roller cam with a faster opening and closing ramp profiles require high rate valve springs or valve float will occur at a lower RPM than with a flat tappet camshaft. You need at least 140 lb. seat pressure and 310 lb. open pressure with roller camshaft and no more thanb .500" valve lift with stock Vortec heads. . Don't use factory valve springs or make comparisons to factory roller cam valve spring rates. The factory valve springs are low rate springs that are designed for extended valve seat and valve train life and are used with light weight titanium and sodium filled valves.

If you buy an aftermarkt RV type flat tappet camshaft, you will be buying a copy of a stock camshaft and will be paying extra for the brand name.

My suggestion:
Purchase an aftermarket camshaft with no more than .500" valve lift, no more thanb 218 degrees duration and valve springs that have at least 130 lb.seat / 310 lb. open pressure. Machine work will be required to fit those type valve springs. Higher valve spring pressure and stiff rear end gears are not required because you will run out of engine at 5,500 RPM. With no more than 9.3:1 compression ratio, 87 octane pump gas will work great and you can also keep you stock radiator because you will not be driving on the freeway with the trucks and busses.

Last edited by MouseFink; 09-21-2013 at 01:04 PM.
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Old 09-21-2013, 08:27 PM
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Based on what I've tried with my pickup, I have some suggestions.

Your truck is heavy and 3.50 or 3.73 gears are just barely enough to get the it moving off the line. With a 700R4 (3.06 low gear and .70 overdrive) you would be better off with about 4.10 gears. I am assuming you have standard height pickup tires, which are usually about 31".

218 @.050 cam duration is probably a little too much for your current combination in a vehicle this heavy, although with additional power from the Vortec heads it might be okay. You need more gears (as above) and a higher stall torque converter to get the vehicle moving. I think you would be happier with a dual pattern RV cam of about 204/214 @.050. If you want to save a little money you can use one of the Summit cams and new lifters.

A roller cam would be a very good choice, but a lot more expensive than a standard cam. I'd try a standard cam first with a good break-in, making sure to also switch to a motor oil with high ZDP content. For example, Mobil 1 15w50 has high ZDP/Zinc and it is sold at WalMart, Autozone, etc.

Bruce
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Old 09-22-2013, 12:19 AM
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What kind of pickup is it going in? There's a big difference between a lowered 60's c10 and an 80's crewcab 1 ton.

Hotrodding around town, or hauling hay down the Highway?

I built a 350 for my '80 K20 with 186 heads, 9.35:1, and a sum-1103 cam (214/224@.050) and I have to back the timing off a bit and run 91 octane to haul more than a few thousand pounds, but just hotrodding around town, I've got plenty of get up and go on mid-grade.
I'm running a 4spd granny tranny, so that definately helps with any lack of low end tq, but even so, I'd go with a size bigger cam if I were to do it again.

If you're worried, go with the Sum-1102, but don't expect to wind it past 4500..

BTW, all the summit cams are under $100 for a cam/lifter KIT.
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