|11-22-2007 03:01 PM|
I seem to be leaning more towards the isky & crane as I'm hearing too many complaints about comp cams. I don't mind a little lope as long as it doesn't rattle the fillings out
of my teeth ! The car has collector plates on it so I have to stay with orig. intake and exh. manifolds and basically keep the car looking original.
I don't race the car, more of a summer street cruiser, but it's nice to have the extra kick there when you need it. Also want the engine to complement the new 3:55 gears and M20. The car originally came with 2:73's but was brutal off the line so I went up to 3:55's
The 3:55's made a difference but it's still lacking in torque. Now I've installed a 4 speed but haven't taken the car out yet, thought I would start on the motor while I'm at it. Thanks for all the pointers F-Bird !
|11-22-2007 01:51 PM|
It's a little more aggressive than a stock cam but not yet lopey.
the Isky 20124/271-12 is very similar. Both have good idle vacuum. both will make a little more low/mid range torque than the old 327-350HP 151cam.
What idle are you looking for? Remember as you increase duration and overlap the idle gets rougher (sounds cooler) but the torque curve gets shifted up in the rpm band, which reduces low rpm torque. manifold vacuum is also reduced.
Either of these cams will make a good bit more power than the stock 327-275/300hp cam (929 cam) but will have a little stronger low/mid end torque than the 327-350HP 151 cam does, by the effect of the the shorter intake duration.
In your motor, these cams will give up nothing in peak HP to the 327-350hp cam. Just a little nicer nature if you drive your car more than you race it.
If you want to improve the 327 cylinder heads, keep the 1.94" intake valves and go to to a 1.60" exhaust valve. Then fully port the ports. By fully porting your heads I do not mean take it to the absolute biggest possible race port size. I mean fully rework the ports including the bowls, short side radius, valve guide boss contour shape.
You can gain all the airflow and power you'll ever need (for this motor) without going to a 2.02 valve. The 2.02 valves requires specific chamber reworking to pay off.
This combined with a moderate cam like ones I recomended will get you a good bit more power and torque than what you started with, without getting carried way.
|11-22-2007 11:25 AM|
|super_silent||Funny you should say that......I've alway's used Comp Cams and never had problems but a guy in town here who is well known for building HP engines won't touch anything by Comp Cams. He say's he's had a few fail on him and comp cams never did anything for him.|
|11-22-2007 09:57 AM|
I stay away from Comp cams
had nothing but problems with their junk.
|11-22-2007 09:00 AM|
|super_silent||Thanks everyone for all the info, with all the different cam grinds out there this will make things alot easier.|
|11-21-2007 12:38 PM|
The 268H or the nostalgia or that second crane recommendation will run fine.
Head work is a real good idea. Bigger valves will help, but smoothing out the bowls after the bigger valves are put in is critical. Your heads will flow worst with the bigger valves if bowl smooth is not performed. Bowl smoothing is the low hanging fruit in cylinder head porting. You can pick up 20 easy hp with this procedure.
|11-21-2007 11:11 AM|
I'm really not that knowledgeable on lift and duration specs
but I'm looking for something to squeeze out a few more horses without a really lopey idle. I don't mind a little lope but the car has power brakes as well. I'm also considering getting some work done on the heads as well, I think the heads have 1.94 or 1.96 valves, which I'd like to change to 2.02's
|11-21-2007 10:31 AM|
I looked up the specs on compcams website.
258/265 advertised duration
211/218 duration at 0.050"
This cam will have a good idle. I wish the lift was around 0.450" and the LSA was 110.
A 268H has 268/268 advertised duration
218/218 duration at 0.050"
lift is around 0.450" ( i forgot).
It also has a little lope and will make power to 5800 with a 327. The 110 lsa with help the low speed torque.
|11-21-2007 09:39 AM|
Comp's "Nostalgia" cams came out a couple years ago, but never got a big splash. I think Summit used to offer them. I could never figure out how they could offer the performance of the older cams with newer technology, i.e. different grinds. Maybe I missed something.
Anyway, I believe the 300hp factory cam was just the old "929". I've found a good replacement is the "151" mentioned above: 222/222 @ .050 and .447 lift.
|11-21-2007 09:14 AM|
Here are a couple you may consider if a rumbly idle is your goal, without giving up much torque. They're older grinds that are easy on the valvesprings and not noisy at all.
|11-21-2007 08:59 AM|
I don't think you'd notice any difference between the original cam and the 300HP cam. Probably the same cam, if you're talking factory cams.
If you want a little more cam, you might want to try the 350HP cam. I think the last 3 numbers of the original 350HP cam were 151.
It'll give you a little bit of a lope, but is very streetable, especially with a 4 speed. Or you would get about the same effect with any of a number of more modern grinds, such as any of the cams mentioned earlier.
|11-21-2007 08:39 AM|
The 327 is pretty much stock, it has the camel hump heads on it and I believe the compression ratio is 10 : 1
I've had the quadrajet slightly modified and added a pertonix distributor & coil.
Here are the specs on the Nostalgia cam:
Product SKU: CAM CL12-670-4
HYDRAULIC-Sound of GM 300HP camshaft with improved power and performance.
Intake/Exhaust Lift: 426/420
Intake/Exhaust Adv. Duration: 258/265
RPM Range: 1000-5500
|11-21-2007 06:59 AM|
Sorry, I haven't used one of those cams. What are the specs?
duration at 0.050"?
What is the 327's compression ratio?
I would use an old school compcam 268H. Those new high lift flat tappet cams tend to go flat quickly, especially with todays reformulated engine oil. I'll give up a few horses to allow the cam to live longer than a month.
Use diesel engine oil or an EOS additive with your new cam.
|11-21-2007 12:17 AM|
what is the comp cams #12-208-2 idle like ?
|11-21-2007 12:05 AM|
Comp Cams does a good job of marketing the latest trick of the week flavour cams. Their Thumper rabbit cams are a good example.
The nostalgia serious are modern interpretations of the old factory cams
The 300+ cam grind is a little short on valve lift. Valve lift is good for making torque. (with short/moderate cam duration)
I would look for a similar .050 duration cam with a little more valve lift.
Isky #201264/271-12 or Comp cams #12-208-2 are good.
use a Isky 205D or comp 981 or Lunati 73943 valvespring.
A mild Lunati Voodoo cam like Lunati #60100 or 60101 would work very well also.
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