What cam to use? Little advice needed SBC

R

rustorbust

Member
So I have my motor apart that I had in my Datsun 280z. Its more or less a stocker 350 with a set of dished forged pistons (Speed Pro ZLW2603F30). I originally put it together with a bunch of crap parts laying around....set of crappy 882 heads, new grind of the old 30/30 cam, single plain torker intake. Needless to say, it got the car putting around but was a total toad. So I have been collecting some parts (more stocker stuff but better), I had a set of 3947040 SBC heads that i had rebuilt and a good set of springs installed that im going to be using on it now. Question is, What cam should I run in it and what intake. The heads have been machined down and the spings are able to take up to a .575 lift cam. I want to be able to get as much out of this little motor that I can now.

Some of the other parts and stuff surrounding the motor are....Harland sharp 1.5 roller rockers, Stock Hei (do have a pro billet i can run in it with a 6al if I need to), I have both a 650DP or a 750DP that I can run on it, 1 5/8 block huggers, 2.5" duals to one 3" that collects under the diff and goes to a 2 chamber muffler, World class t5 trans.

Any advice is much appreciated....Thanks

James
 
is it a manual or auto transmission,?
if an auto trans , whats the stall speed?
and do you know your rear gear ratio ?
and your compression ratio?
are you willing to run high test gas ONLY?
will this be a weekend toy or daily transportation?
are you willing to lash solid lifters?
Im assuming this is a budget build so a roller cams out due to cash flow issues most of us have?

because the answers to those questions both restrict and point to the correct choices
of course you'll want to match the heads you select,
to the intended rpm/power range and application and match the cam timing, compression ratio, and drive train gearing, etc.
so lets discus the current car/truck weight, transmission, tire size, rear gear ratio and what your intended goals and budget limitations are, as a start point.
the last thing you'll want to do is select parts that may cripple or restrict the engine performance by mis-matching components or selecting parts on price alone, we all work on limited budgets,
but its will pay big dividends in power produced too carefully select matched components
and generally the biggest mistake is mis-matching heads, intake and cam combos or scrimping on the quality of the components used,
a couple extra hours or even days spent in detailed of research may prove critical, in fact anything less than buying and reading through several books and reading a couple dozen links and all the sub-links is very likely to leave you missing valuable and critical info youll need later, and thats usually going to cost you wasted time and cash.
the big mistake's most people make is in not selecting the correct cam, to match the displacement and compression and drive train gearing or selecting a restrictive cylinder head or intake that does not match the intended power range

yes it looks over whelming but youll be amazed at the detailed info and the mistakes you can avoid by reading carefully
http://garage.grumpysperformance.com/index.php?threads/sellecting-cylinder-heads.796/

http://garage.grumpysperformance.com/index.php?threads/semi-fool-proof-cam-sellection.82/

http://garage.grumpysperformance.com/index.php?threads/first-hotrod-build.12902/#post-67005

http://garage.grumpysperformance.co...ing-a-383-sbc-combo-planing.12168/#post-58778

http://garage.grumpysperformance.com/index.php?threads/bare-minimum-tools.11026/#post-48785

http://garage.grumpysperformance.com/index.php?threads/matching-parts-and-a-logical-plan.7722/

http://garage.grumpysperformance.com/index.php?threads/what-to-look-for-in-a-good-engine-combo.9930/

http://garage.grumpysperformance.com/index.php?threads/another-383-build.12786/

http://garage.grumpysperformance.com/index.php?threads/383-information-overload.11137/

http://garage.grumpysperformance.com/index.php?threads/a-383-build.10991/

http://garage.grumpysperformance.com/index.php?threads/impersonator.9600/

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.com/index.php?threads/port-speeds-and-area.333/

http://garage.grumpysperformance.com/index.php?threads/valve-seat-angles-and-air-flow.8460/

http://garage.grumpysperformance.com/index.php?threads/tbucket-engine-project-dart-shp.3814/
 
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Its has a World Class T5 5 speed, Rear gears are 3.54 with a 235/60/15 tire, Compression ratio will be 9.5 to 1, I want to be able to run it on 91 octane since it is a weekend car that I will run every once and a while at the local 1/8 mile stuff. I have no problem running a solid flat tappet setup...and yea, wasnt looking to spend the money on a roller setup. Thanks Grumpy
 
ok IL assume you don,t mind a lopey idle and want to maximize the power curve?
with the manual transmission gearing and your cars light weight and short wheel base you can get along with a bit more cam duration that a heavier combo could pull off, your small exhaust is slightly restrictive so a longer exhaust duration will most likely help, you'll want to maximize the mid rpm torque curve due to the 3.54:1 rear gear and street use, both the cams listed below are similar but have slightly different duration and lift Id doubt there will be a 20hp difference but the engines driving characteristics will be noticeably different so....

the components below should kill off a bit of low rpm tq but more than compensate above 3500rpm-6500rpm for that slight reduction in low rpm power, the components in green would be my choice for your car but it will run rough at low rpms and pull hard over 3500rpm so you will need to drive the car like you stole it to maximize the components potential.

ID suggest this cam, if you don,t mind a very lopey idle
http://www.crower.com/misc/cam_spec/cam ... 5&x=35&y=6


and this intake for general use
http://www.midwestmotorsportsinc.com/or ... 6&line=MWM


and Id point out that this intake,(below) could be substituted, but while it will produce better peak hp it will cost you a bit more low rpm torque, and the single plane intake is a better choice only if the object is far more toward long high speed track racing, where the engine spends a good deal of time at peak rpms than general use

http://www.midwestmotorsportsinc.com/or ... 1&line=MWM

this cam on a wider LSA will idle smoother and allow use of slightly lower octane fuel, but won,t be as crisp, but it will be easier to drive in traffic and will be a good choice on the street (your choice, either cam will be a decent choice)but on the plus side it has a wider useful power band allowing you to hang in each gear a bit longer, combined with the second intake it would be more of a high speed, track cam vs the first cams road race, pull from the corners type tq curve, combined with the first dual plane you'll get a smoother idle and a good street/strip combo but give up a bit of lope to the idle and peak torque, but gain better street manors
http://www.crower.com/misc/cam_spec/cam ... 1&x=46&y=7


keep in mind that a much better flowing set of heads like the BRODIX 200cc IK will really wake up the engines power curve, if matched to those components listed above in the future, as your budget allows
http://www.jegs.com/i/Brodix/158/1021001/10002/-1
 
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