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Old 01-06-2008, 07:48 PM
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283 cam choice

Im bolting together a 283 and Ive got quick camshaft question.

The motor will see action in a '79 Buick Regal. No street, no strip, just backwoods, unsanctioned dirt track racing. Safe? Not really. Fun? You bet!

My question is this.. will I pull the studs out of the heads running a short lift, loooooong duration cam? The cam Ive got in mind is an Isky grind, part #201LR4. .420 lift / 296 adv. duration / 248 duration @ .050.

There really isn't a good reason at all to run such a large cam. Performance doesnt matter much because of the 'bald tire' rule. Good tires arent allowed, mostly to keep the ragged out cars from achieving a highly dangerous speed. Id like to run such a cam because Im not old enough to have experienced the glory days of small cube sbc's wound to the moon and Id just plain like to operate one myself. Heck Ive never even heard a small block spin past 6500r's.

Will the press fit studs stay in the heads? Will I be able to break that cam in without flattening it? Will the valve springs keep the valves away from the pistons? Any advice is appreciated.

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Old 01-06-2008, 09:18 PM
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Hi John,
Sounds like fun,
283 + .060=292
Vortec heads w/1.94/1.500 valves from GM Performance
pn. 12559060
Speed Pro domed forged pistons#L2275F
for about 101/2.1 CR
Edelbrock Super Victor intake for the Vortec's pn. 2913
Should spin well past 8,000

Also you can have the block sonic tested to see if you
can bore it .125 over making it a 4" bore =302ci
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Old 01-07-2008, 06:44 AM
How fast is fast enough?
 
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I would use screw in studs at that high of an RPM range. Along with super stiff spings, and good pushrods. The super victor is way overkill for that engine, hell a Performer RPM would run fine at 7,000 RPM in a 283. Also IGNITION becomes a limiting factor at those engine speeds. Hitting 8,000 RPM in a small block is not as easy as it sounds.
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Old 01-07-2008, 02:50 PM
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Yup Richard Steward that combo would be nice, but Im not planning on dumping a pile of money into this motor. Ill be using the stock bottom end, freshened up with rings and bearings, and the stock 60cc cylinder heads.

In short, is my thinking correct that a short lift, long duration cam will be somewhat easier on valvetrain parts? Or will it come apart immediately?
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Old 01-08-2008, 06:30 AM
How fast is fast enough?
 
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as long as you don't rev it above 6500 you'll be fine... but if you really want to rev to the moon then you need to pay for the space shuttle.
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Old 01-08-2008, 01:45 PM
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Unless you raise the compression ratio to over 11:1 that cam will be a mutt in a stock 283. that cam needs 12:1+ in a 283 to make power.

Does your 283 have a flat top piston or a domed piston?
On a flat top piston 283 you want a combustion chamber volume of 48 to 50cc using a thin shim head gasket.
You need to maximize the compression ratio, regardless.
Max mill the heads to get the compression ratio up higher. (consider using milled small chambered 53cc #601 (267-305) heads and use a thin steel shim head gasket.

Use Isky #201278 "278 Mega-cam" Hyd camshaft. 234-234@.050 106LSA .450" lift. Degree in the cam and install advanced on a 102 intake lobe C/L. (4 deg advanced) It will rev like no tomorrow. And actually make some power.
Use Isky anti pump up hyd lifters. Drill and roll pin the rocker stud bosses. Get some Lunati 73943 valve springs and a comp #4753 shim kit. Shim for a 1.68" to 1.70" installed height.

Modify the distributor advance curve for more initial advance at idle. (34-36 total) and about 24deg at idle.

Use a dual plane hi rise RPM style manifold.

Last edited by F-BIRD'88; 01-08-2008 at 04:10 PM.
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