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Author
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Topic: How much cam can stock valve train handle?
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mustangboy
Gearhead Posts: 1147
From: Ont, Canada
Registered: Mar 2002
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posted 08-29-2002 02:19 AM
  
I am building an original low mileage 66 289.I was planning on using a dual plane high rise intake like the ones they used on the shelby's and some tri-y headers.I would like to slip in a small cam but I don't want to get into having to go to screw in studs.How much spring pressure can the stock valve train hold and what cam should I use.This isn't going to be a race car and will probably never see the track but it must be reliable as I am building it for my sister who lives about 2000 miles away so I can't run out and repair it if something goes wrong.Oh by the way the car is a 66 coupe with a 4speed and 3.20 gears.
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Gearhead
Gearhead Posts: 2177
From: Brisbane, Australia
Registered: Mar 2000
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posted 08-29-2002 12:16 PM
I'm running a CompCam Extreme Energy 262H ( 218/224 duration @ 0.050, .493"/.500" lift) with the basically stock valvetrain in my 79 Pace Car's 302. It pulls up to 6000 rpm with no sign of valve float, and everything seems to be perfect. It's a GREAT little cam. Plenty of torque, and good high end breathing. It has a nice idle that lets people know it isn't stock, but has no problem idling at 700-750 rpm. I would highly recommend this cam for a nice little street engine(as people on this board did to me when I was originally trying to decide on a cam).FYI, the rest of my combo includes a hi-rise Shelby intake, Holley 600 VS carb, shorty headers, 2.5" off-road H-pipe, Flowmaster 2 chambers (LOUD!) T-5 transmission and 3.73 gears. The bottom end is fresh with 0.040" over flat-top pistons with relatively small eyebrow reliefs, crank ground .010/.010, and a hi-volume oil pump. The heads had some bowl work done to them, plus a 3-angle valve job, and fresh springs, but nothing wild or exotic (i.e. stock bolt-down stamped steel rockers). ------------------
Cheers,
Ian
M&M Member #395
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'79 Mustang Indy 500 Pace Car
Ian's Pace Car Website
Vancouver Island Mustang Association Website
Indy Pace Car Registry of Mustangs Official Website "A friend will bail you out of jail after you do something stupid... a real friend will be sitting beside you saying 'That was SO COOL!!'". [This message has been edited by Gearhead (edited 08-29-2002).]
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mustangboy
Gearhead Posts: 1147
From: Ont, Canada
Registered: Mar 2002
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posted 08-29-2002 01:12 PM
Thanks for the reply Gearhead, but I've got the old style pressed in positive stop studs.I'm worried that they may start to pull out if I go to a stiffer spring.Did you keep your stock valve springs?
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Gearhead
Gearhead Posts: 2177
From: Brisbane, Australia
Registered: Mar 2000
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posted 08-29-2002 02:33 PM
quote:
Originally posted by mustangboy:
Thanks for the reply Gearhead, but I've got the old style pressed in positive stop studs.I'm worried that they may start to pull out if I go to a stiffer spring.Did you keep your stock valve springs?
Yep, I put new stock valvesprings in when I rebuilt the engine (with a different cam that was a bit less agressive than the XE262H) but reused them with this cam, as they only had a couple of thousand miles on them when I did the swap. No problems at all. I rev the engine to 5500-5800 without any hint of valve float. I have taken it to 6000 on a couple of occasions, but there isn't much need to rev the engine that high (especially since it isn't balanced). It makes most of its power between 3500 and 5500, which is great for the street. My rockers are the later bolt-in style, which are a bit different from the pressed-in ones that you have (not sure if they are stronger or what?). I can't see it being a big problem though, as this cam isn't too radical. Maybe someone with the same vintage of head can jump in here and give a more informed opinion with regards to the limits of the press-in studs??  ------------------
Cheers,
Ian
M&M Member #395
-------------------
'79 Mustang Indy 500 Pace Car
Ian's Pace Car Website
Vancouver Island Mustang Association Website
Indy Pace Car Registry of Mustangs Official Website "A friend will bail you out of jail after you do something stupid... a real friend will be sitting beside you saying 'That was SO COOL!!'".
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smblk t-bolt
Journeyman Posts: 93
From: port alberni BC Canada
Registered: Apr 2002
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posted 08-29-2002 08:55 PM
quote:
I would like to slip in a small cam but I don't want to get into having to go to screw in studs.How much spring pressure can the stock valve train hold and what cam should I use.[/B]
Ive been running 69 351 heads with hi-po 289 springs for at least 6 years.the studs are still pressed in and its gone thru 2 different cams:first was a "no-name" 224-234@050/496-520 and the current one, a lunati 230@050/512 (for the last 3 years)never had a problem with either.the only one that gave me headaches was one with
244@050/540 which floated the valve on the original springs and broke a stud(I know, waaaay too much cam but whattheh*ll!)  64 fairlane
lots of fiberglass
even more bondo
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