camshaft for torque

[lobster]

ok my last post was a little general to say the least,so ill start on the basics

(this is for a 350 chevy sb by the way)

being a series III landy my 'racer' is quite heavy. obviously being a heavy off-roader while being used for daily driving it needs a short duration cam with buckets of torque. BUT ill be doing rallies etc. so ill be reving it at times too, so just a little top end power would be good (max 5500 rpm)

having looked around/read the tech, i was thinking of....
around 112 lobe separation
215 degress duration at 0.050
270 duration
0.500 lift

any particular makes to go for? Crane or Comp Cam prehaps.
will i loose a lot of top end power if reduce the duration by 5 or 10 degrees for more torque and mid power? is this combo ok as a start point?
cheers guys

[73RS]

What motors do they put in those rovers? Cubic inch and bore and stroke? Longer stroke will allow you to get away with a little more duration while still maintaining good low end torque.
I'm not at all familiar with a Rover engine though.

[Don Shillady]

Well with my limited experience with the SBC I have refered Lobster to several SBC sites so other folks should know that maybe Lobster is thinking of putting a SBC in his Rover, is that so? Otherwise what is said above is also true that increasing the stroke in whatever engine does help low end torque. Lobster, the thing to do is specifically tell us what engine you are looking at and somehow get Tech1 to reply or even send him an e-mail. He forgot more than most of us know about cams, although some other folks on this Forum also know about how to wring torque/HP out of a V8 whether Ford, SBC or Mopar. Try to tease Tech1 into an answer and consider carefully what he says but you need to spec your engine more completely.

Don Shillady
Retired Scientist/teen rodder

[76GMC1500]

My Comp XE256H cam did a 2.3 second 60' in the quarter mile in my 76 GMC half ton equiped with a stock 1200 rpm torque converter and 3.07 gears. Tires were BFGoodrich Long Trail 265/70r15, nothing super sticky. It ran 15.3 overall in the quarter mile at 88 mph. Bascially, it makes a lot of torque to get the lump rolling with only 3.07 gears. I'm guessing around 420 ft lbs at the crank. The cam really runs out by 5500, though. An XE262H will make power well through 5500 rpm. I'm also running just a performer intake, if you ran a performer rpm intake with the XE256, it would probably wake up the top end a little.

[lobster]

Bugger! Forgot the minor detail....... yes im talking about a chevy 350. Ive had enough of crap rover engines.

im not too keen about increasing the stroke as i want to keep engine size down for ecconomy and engine classes for competitions. maybe in the future eh?

the Comp XE265H sounds good, as i probably wont be going over 5500 revs. 420ft lbs would be great though.

would it be better to go for the XE256 with the performer RPM, or the XE262 with the performer if i wanted to gain a tiny bit of top end with minimal loss of torque?

[76GMC1500]

If you went with the XE256H cam, you could go with either manifold. If you went with the XE262H, I would most certainly go with the RPM manifold. The motor I put this cam in is a 9.25:1 compression 350 with Vortec heads. If you're feeling rich, you could just buy both manifolds and try them both out. Also, match it up to a set of small diameter long tube headers. 1 5/8ths in primaries and a 2 1/2 inch collecter.

[Ross]

i have a 292H Comp cam in my s10, nice cam, lots of lift, lumpy, ROUGH idling, no complaints, RPM Range is 2500-6500.

[erik erikson]

Originally posted by Ross
i have a 292H Comp cam in my s10, nice cam, lots of lift, lumpy, ROUGH idling, no complaints, RPM Range is 2500-6500.

I THINK HE IS LOOKING FOR A CAM WITH LOW END TORQUE NOT SOMETHING HE HAS TO RUN A 3,000 STALL WITH.

[Ross]

HEY LOOK I CAN RIGHT IN CAPITALS TO!

look at a 292's specs. the duration is 292 but the lift is exactly what he is looking for. hydraulic street cams dont come in that lift and duration combo. He may want a 4X4 Comp Cam though.

lift is .480, duration is 270 1300-5600 rpm range.

Xtreme 4x4 X4262H Hydraulic Flat COMP CAMS

[erik erikson]

Originally posted by Ross
HEY LOOK I CAN RIGHT IN CAPITALS TO!

look at a 292's specs. the duration is 292 but the lift is exactly what he is looking for. hydraulic street cams dont come in that lift and duration combo. He may want a 4X4 Comp Cam though.

lift is .480, duration is 270 1300-5600 rpm range.

Xtreme 4x4 X4262H Hydraulic Flat COMP CAMS

UMMM,YOU MIGHT WANT TO TAKE A LOOK AT THE HYD. ROLLER CAMS COMP. CAMS SELLS.WELL WOULD YOU LOOK AT THAT .500 LIFT ON BOTH THE INTAKE AND EXHAUST SIDES AND 215* AT .050 VALVE LIFT.I THINK THOSE WHERE THE SPECS. HE WANTED.PART #08-420-8. OH,BY THE WAY DO YOU HAVE PRINCE ALBERT IN A CAN? ANYONE, ANYONE, L.O.L.

[techinspector1]

lobster, the key to doing what you say you want to do is a looser converter. Any cam you screw into a naturally aspirated motor will have an effective "window of operation" of about 3,500 rpm's, so nobody can grind you a cam that will operate effectively off-idle to over 5,000 rpm's with a stock converter.

Here's an example of a cam that will give you low-end grunt from 1,000 rpm's with a stock converter, but runs out of breath at 4,600 rpm's..... It is ground on a 110 centerline.....
http://www.cranecams.com/?show=brows...tType=camshaft

Here's the next cam on the list, making power from 1,400 to 5,000 rpm's. Personally, I'd be using a looser converter in the 1,600 to 1,800 stall range with this cam if I were doing it....Also ground on a 110 centerline.....
http://www.cranecams.com/?show=brows...tType=camshaft

This cam may be getting closer to what you're looking for, making power from 1,600 to 5,400 rpm's, but again, personally I'd install a converter with a stall of 1,800 - 2,000 rpm's.....again, 110 centerline.....
http://www.cranecams.com/?show=brows...tType=camshaft

Let me say this about specing a cam. Crane probably has the most realistic power range listings of any grinder I've used. Some of the other grinders will lead you to believe that their cams have an effective window of operation of well over 4,000 rpm's, but it just ain't so, not naturally aspirated it ain't.

Pay close attention to the required static compression ratio to be run with any cam you put in the motor and try to build the motor to the middle of the c.r. spec with zero deck and a 0.039" compressed gasket for a tight squish. That will allow you to run normal spark lead on crap pump gas.

As far as manifolds, I'd use a standard Performer with any of the 3 cams I've listed to keep velocity up for good cylinder filling. Read these recommendations from Edelbrock and make your own decision, paying attention to the operating range of each.....


Performer® Manifolds (idle to 5500 rpm)
Performer manifolds are dual-plane, low-rise intake manifolds with a 180° firing order and patented runner design that you won't find in other brands. This patented design greatly improves torque over a wide rpm range for excellent throttle response, especially off-idle through the mid-range. Throttle Performers are ideal for passenger cars, trucks, 4x4s, tow vehicles and RVs. There are EGR and non-EGR versions available for most domestic V8 and some V6 engines. Most Performer intakes are 50-state street legal, when used with the correct carburetor and in the correct application.

Performer RPM™ Manifolds (1500 to 6500 rpm)
Performer RPMs are dual-plane, high-rise intakes with 180° firing order to produce incredible top-end horsepower while retaining good throttle response. Their larger plenums and runners match the free-flowing exhaust, high-lift cams and other modifications of a high output engine. They are intended for high-performance street or competition engines that run up to 6500 rpm. They are not for emissions equipped engines. Edelbrock's Performer RPM gives you the ultimate in street high-performance.

One last thought, keeping in mind that power is in the heads, pay attention to the post by 76GMC1500 about the Vortec heads. They will outflow any of the Gen I Chevy heads ever produced and will make excellent full-time-street / part-time-track heads.

[lobster]

Cheers Guys!

looks like the 272 H10 (the last crane cam from techinspector1 - cheers) is what im looking for. just seems to have a much better top end with only a little sacrifice in idle etc. duration looks fine. prehaps 1.6:1 rocker ratio on the exhaust valve to improve lift?

As for the manifolds, looks the Perfoprmer kicks the RPM's ass for torque, so ill prob go for that. has anybody tried the performer air-gap or the performer EPS???? is the air gap woth the extra 100 bucks?

vortec heads would be nice but probably a bit pricey (plus having to buy special manifolds etc). IF i had a bit extra to spend, what would people recomend to buy...

full roller valve train (so higher lift cam can be used)
OR vortec heads with a standard valve train??

maybe just sell my kidneys and buy a supercharger..... mmmmmm

[techinspector1]

Personally, I'd spend money on good heads before ANYTHING else. They will be the foundation for whatever else you want to do to the motor.

Let me give you a combination to think about. You can embrace it, modify it or discard it completely, but this might be how I'd do it...

350 block bored 0.030"
Scoggin-Dickey #KB193-030 Keith Black hypereutectic pistons (12 cc dish) $31.25 each for use with 3.480" crank and 5.700" rods.

I like these pistons particularly because of the way the dish is offset to one side of the crown, allowing a generous squish pad to mate up with the squish pad on the Vortec heads.
http://kb-silvolite.com/performance....tails&P_id=155

GM 12495499 head bolt kit $24.95
GM 10105117 Vortec head gaskets (0.028" compressed) $15.45 each
GM 12495490 rail rocker arms (kit of 16) $49.95

These rockers have rails on each side to form a "trench" for the valve tip to ride in so that the rocker will stay centered on the tip without the additional expense of machining the heads for use with guide plates.

Fel-Pro FEL1255 intake gaskets (pair) $23.95
Edelbrock #E2116 Performer intake manifold $158.95
Scoggin-Dickey #SD12550027 12 point intake bolts (kit) $14.95
GM 10046089 valve cover gaskets $9.95 each
GM 12558060 Vortec heads assembled with 1.940" intake / 1.500" exhaust valves, single springs for max 0.450" lift, retainers and keepers $249.75 each

Scoggin-Dickey #BG4282010VE Barry Grant Road Demon 625 cfm vacuum secondary carb $339.95 or my personal favorite, the Rochester Quadrajet Scoggin-Dickey #E1901 Edelbrock 750. $449.95. Don't let the 750 throw you, it's not too much carb due to the tiny little primaries for excellent mileage and throttle response and the huge secondaries for power when needed.

Crane 100052 hydraulic camshaft (not listed in Scoggin-Dickey catalog, but could probably be sourced from them on special order. I'm just trying to source all parts from one supplier) Vortec heads are limited to 0.450" lift with supplied springs and this cam has 0.454" lift, talk with the tech guys at Scoggin-Dickey to find if this cam should be ground with a little less lift to work with stock Vortec springs, retainer/seal clearance.)

By the way, you mentioned 1.6 rockers on the exhaust. You won't need them with the Vortec heads. 1.6 rockers are used to crutch-up poor-flowing exhaust ports in relation to intake ports and the Vortec heads are well-balanced as cast. You'll see that some cams for the SBC are ground on a dual pattern, more lift and more duration on the exhaust side and again, this is to crutch-up the poor-flowing (relative to the intakes) stock Chevy exhaust ports. You also won't need any more lift than 0.450"/0.454" with these heads in a street application with mild track time. They flow so well that you don't need an excessive amount of cam lift to crutch them up like you might need with stock OEM Chevy castings.

Scoggin-Dickey #CRA99377-16 Crane High-Intensity lifters. $119.95 set of 16. These are fast-bleed lifters that produce a variable duration effect. At lower rpm's, these can reduce running duration by 6 to 10 degrees and decrease valve lift by 0.020" to 0.030". This controlled oil pressure increases cylinder pressure and performance in the lower rpm range without sacrificing duration and lift in the upper ranges. Somewhat like having your cake and eating it too. You may be able to run a stock converter with this cam if using these lifters. Talk to the tech guys at Crane.

Assemble the motor with the pistons 0.012" down in the bore at TDC. This will give you a squish of 0.040" using the 0.028" compressed head gaskets and will allow you to run pump gas without detonation at the calculated 9.65:1 compression ratio with the 64 cc Vortec heads and 12 cc KB pistons.

Set initial timing at the crank at 12 degrees and re-curve your distributor for total initial and centrifugal timing of 36 degrees, all in by 2,800-3,000 rpm's. Adjust fuel pressure for 5 1/2 to 6 lbs at the carb inlet. Degree the cam according to the instructions from Crane. Include a way to advance or retard it by 4 degrees after you have the motor running (offset dowel or whatever). That way, you can tailor the cylinder pressure higher or lower according to what you think you need.

Valve covers for Vortec heads...
12355350 GM Chrome With Red Bow Tie In Center
SCTZVC New “Take Off” ZZ-4 Black Valve Covers (When Available)
24502540 Valve Cover Adapter, Converts Center Bolt To Outside Bolt
10046089 Center Bolt Valve Cover Gaskets (price is for one gasket)
241-75 Holley Custom, Cast Aluminum, Ball-Milled Top, Valve Covers. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise. (Pic)
241-74 Holley Custom, Cast Aluminum, Polished Flat Top, Valve Covers. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise. (Pic)
9415 MR Gasket, 87 & up SBC , center hold down, baffled. (2 covers, 1 oil fill cap, 2 PCV/breather grommets.) (pic)


Scoggin-Dickey Chevrolet website/catalog....
www.SDPC2000.com

O.K., the old tech guy is tired from all this and is going into the other room for a nap

[erik erikson]

Originally posted by techinspector1
Personally, I'd spend money on good heads before ANYTHING else. They will be the foundation for whatever else you want to do to the motor.

Let me give you a combination to think about. You can embrace it, modify it or discard it completely, but this might be how I'd do it...

350 block bored 0.030"
Scoggin-Dickey #KB193-030 Keith Black hypereutectic pistons (12 cc dish) $31.25 each for use with 3.480" crank and 5.700" rods.

I like these pistons particularly because of the way the dish is offset to one side of the crown, allowing a generous squish pad to mate up with the squish pad on the Vortec heads.
http://kb-silvolite.com/performance....tails&P_id=155

GM 12495499 head bolt kit $24.95
GM 10105117 Vortec head gaskets (0.028" compressed) $15.45 each
GM 12495490 rail rocker arms (kit of 16) $49.95

These rockers have rails on each side to form a "trench" for the valve tip to ride in so that the rocker will stay centered on the tip without the additional expense of machining the heads for use with guide plates.

Fel-Pro FEL1255 intake gaskets (pair) $23.95
Edelbrock #E2116 Performer intake manifold $158.95
Scoggin-Dickey #SD12550027 12 point intake bolts (kit) $14.95
GM 10046089 valve cover gaskets $9.95 each
GM 12558060 Vortec heads assembled with 1.940" intake / 1.500" exhaust valves, single springs for max 0.450" lift, retainers and keepers $249.75 each
Scoggin-Dickey #BG4282010VE Barry Grant Road Demon 625 cfm vacuum secondary carb $339.95 or my personal favorite, the Rochester Quadrajet Scoggin-Dickey #E1901 Edelbrock 750. $449.95. Don't let the 750 throw you, it's not too much carb due to the tiny little primaries for excellent mileage and throttle response and the huge secondaries for power when needed.
Crane 100052 hydraulic camshaft (not listed in Scoggin-Dickey catalog, but could probably be sourced from them on special order. I'm just trying to source all parts from one supplier) Vortec heads are limited to 0.450" lift with supplied springs and this cam has 0.454" lift, talk with the tech guys at Scoggin-Dickey to find if this cam should be ground with a little less lift to work with stock Vortec springs, retainer/seal clearance.)
By the way, you mentioned 1.6 rockers on the exhaust. You won't need them with the Vortec heads. 1.6 rockers are used to crutch-up poor-flowing exhaust ports in relation to intake ports and the Vortec heads are well-balanced as cast. You'll see that some cams for the SBC are ground on a dual pattern, more lift and more duration on the exhaust side and again, this is to crutch-up the poor-flowing (relative to the intakes) stock Chevy exhaust ports. You also won't need any more lift than 0.450"/0.454" with these heads in a street application with mild track time. They flow so well that you don't need an excessive amount of cam lift to crutch them up like you might need with stock OEM Chevy castings.
Scoggin-Dickey #CRA99377-16 Crane High-Intensity lifters. $119.95 set of 16. These are fast-bleed lifters that produce a variable duration effect. At lower rpm's, these can reduce running duration by 6 to 10 degrees and decrease valve lift by 0.020" to 0.030". This controlled oil pressure increases cylinder pressure and performance in the lower rpm range without sacrificing duration and lift in the upper ranges. Somewhat like having your cake and eating it too. You may be able to run a stock converter with this cam if using these lifters. Talk to the tech guys at Crane.

Assemble the motor with the pistons 0.012" down in the bore at TDC. This will give you a squish of 0.040" using the 0.028" compressed head gaskets and will allow you to run pump gas without detonation at the calculated 9.65:1 compression ratio with the 64 cc Vortec heads and 12 cc KB pistons.

Set initial timing at the crank at 12 degrees and re-curve your distributor for total initial and centrifugal timing of 36 degrees, all in by 2,800-3,000 rpm's. Adjust fuel pressure for 5 1/2 to 6 lbs at the carb inlet. Degree the cam according to the instructions from Crane. Include a way to advance or retard it by 4 degrees after you have the motor running (offset dowel or whatever). That way, you can tailor the cylinder pressure higher or lower according to what you think you need.

Scoggin-Dickey Chevrolet website/catalog....
www.SDPC2000.com

O.K., the old tech guy is tired from all this and is going into the other room for a nap

I LIKE IT ALL EXCEPT FOR THE HEADS.I WOULD TRY A SET OF DART IRON EAGLE S/S HEADS ,AND THEN GO WITH A SET OF SPEED PRO HYPEREUTECTIC PISTONS PART #H631CP.YOU WILL LOOSE ABOUT 3/4 OF A POINT ON COMP. RATIO BECAUSE OF THE CHAMBER SIZE BUT IT STILL SHOULD WORK FINE.AS FOR DEGREEING THE CAM I SAY JUST PUT THE CAM IN (STRAIGHT UP).THIS IS A DAILY DRIVER ANYWAY.GOOBLE,GOOBLE.

[techinspector1]

Erik, is that a nice way of saying you like the cam but everything else sucks?