joshh44

i need some help with choosing a cam.
i have a 1977 chevy 350, 4 bolt main block.
i would like to make it a convert it over so i can use a roller cam. since i have a non-roller block,

i heard so many people saying mixed things on how to do it.
saying you have to bore out where the cam sits. and the pushrod holes.
others say you need to just get a roller cam and get special type lifters.
and other say you need a retro cam.
i ready how to do the conversion thing and i just dont get it. i looked on the web and i still dont get it. they eather ramble on and totally off topic. its frusterating.
anyways can someone just explain how to it?
like step by step kind of thing?
non of these long expaling details about how the part works. i can figure that out on my own. just straight to the point stuff.

and once that is out of the way what size of cam should i use?
im hopinto get 500hp if not more.
im building a 383 stroker with 6" rods. (less side load on the cly walls)
anyways here are the heads ill be using and the specs to help figure out cam size.

Dart SB-Chevy Iron Eagle Platinum Series Cylinder Heads

2.05'' Int/1.60'' Exh Valves
1.550'' Springs, 195lbs @ 1.900''
.690'' Max Lift
Straight Plug
64cc chambers
215cc runners

doc221978

From everything i've read it's no good to try a factory style roller setup over 0.500 lift. I got 0.520, but it's close.

I would recommend a call to comp cams for a grind, and i think it would last longer if you went with a retrofit lifter set. The spider on the stockers doesn't hold to high lift, cause it wasn't designed to be raised up be the lifters.

HiTech5

iTrader: (4)

Josh - In order to run a hydraulic roller in your block, you will need the following:

1.Retro fit HR lifters. These will run you between $450-500.
2.New pushrods sized to the proper length. I recommend 1 piece.
3.New springs with a lightweight retainer or a set of Comp Camps beehive.
4.Thrust button for the timing chain. The roller cam tends to push forward.

sofakingdom

iTrader: (1)

HiTech's list is all it takes.

Roller cam - duh

Roller lifters - People call them "retrofit" nowadays. They're the link-bar style; we've all been using them for decades before the factory created their modified blocks.

Cam button - The lobes of flat tappet cams aren't flat, rather they're sligthly taller on the edge toward the rear of the motor; and flat tappets (lifters) aren't flat either, they're convex, with a radius of curvature of about 6'. This combination, which a roller cam doesn't have, makes the lifters try to hold the cam in (in addition to the load on the dist gear created by the oil pump). A cam button goes between the front of the cam and the timing cover, to hold the cam in place.

Push rods - roller lifters are taller, so the push rods need to be shorter. But you'd be buying push rods no matter what, so it will just so happen that the ones you'll ned for a roller will be shorter than flat tappet ones, usually by about .400".

Valve springs - those would work fine.

The original roller system is so simple, so reliable, so cheap, fits so well in ANY block with NO MACHINE WORK OR MODIFICATION WHATSOEVER, and isn't patented or otherwise protected; kind of makes me wonder why the factory invented all that other stupid crap. I'm sure they had their reasons, I just can't fathom what they are.

Those heads are WAY TOO BIG for a street-driven 350, or even a 383. Likewise, you don't need those big valves; they're so big that the edge of them will be up against the bore (shrouding) in a 4" bore motor. Think about it.... no flow can occur if the vertical surface next to the valve isn't WELL away from it; it hardly matters that you open the valve .600" or whatever, if there's only a .050" or whatever crack around the adge of the valve between it and the next obstruction. They may actually flow LESS than 2.02" ones because of this, in the little motor. Unless you're building a 400 block, stick with the 200s and 2.02" intakes.

joshh44

thanks hightech. i figure it would be about a grand to get a roller setup for my engine. i think ill just go and get a roller 350 block insted.
or just keep my engine flat tappet. im not to sure at the moment. gotta give it some thinking.

i thought they would be alittle big.
you should seen the last heads that i was going to get haha they were like twice the size of these heads with 2.10 valves with 235 runners.
i was always told that bigger is better for engine.
there are some assembled dart heads with 2.02 valves with 200 runners for about $549 each. or bare ones for $350? or so.
if i had to upgrade the springs i think i would just get the bare heads and build em up with quality parts.

sofakingdom

iTrader: (1)

Not a good plan; unless you know, BETTER THAN the head company, what fits and works best with THEIR product, and you have the tools and know-how to do head setup. Much better to buy them already set up like you want them. Usually costs ALOT less, besides.A typical hot-rod myth...

Engines, and CARS as a whole for that matter, work best when all the parts work TOGETHER consistently toward a common goal. Matching stuff works infinitely better than sticking ONE thing in there that's as ginormous as will fit while everything else (cam, intake, exhaust, carb) is sized smaller.

Following that logic, you don't build a street motor with heads designed for 5000+ RPM operation on a LARGER motor than yours and giving up 1500-4000 RPM performance to favor that top range, and expect it to work well. Instead, you pick heads that are matched to YOUR size motor, in the RPM range that YOU will be running it at most of the time, if you want something that you will enjoy and be able to afford to operate.

The 200s are just about perfect for a 383. I'd strongly recommend going that way instead.

joshh44

ill check into some 200 cc heads with 2.02 valves.
well lets say i got thos heads. with lets say. .540 max lift.
what cam setup would bet match thos heads?
i found afew but they were flat tappet style cams. i would like to have a roller style setup.

stevenb

What about sportsman 2 heads? Mine have 2.02/1.60 with 200cc intake runners. What your looking for right? I mean they're an average head, not too bad for the street.