That's what I said in post #171.
My Vortec Combo disappoints
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
let me get this straight, you're suggesting spending $1,500 to swap rear gears; a problem that could be solved with a $200 cam swap? Not to mention that with the higher numeric gear the car becomes harder to drive, wears parts out faster, and gets much worse mileage.... while I certainly understand the idea of laying out all the options - I wonder about at what point the answer is in the weeds....
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Well, you guys certainly sound knowledgeable, but a hydraulic lifter has a spring below the pushrod cup that can compress to avoid lifter noise, wouldn't the hydraulic lifter spring compress when the lifter first starts riding up the cam lobe and the valve stay where it is until the slack is taken up in the lifter spring? In other words, with a hydraulic cam, how can the valve start moving as soon as the lifter hits the start of the ramp?
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Race Director
Joined: Oct 2000
Posts: 15,065
Likes: 79
From: central FL, near the beach.
Super BuickGuy
probably was only 40. that is my point about steep gears. it makes you THINK it is really fast, but it is just an illusion. Long time ago, I track drag raced a 318 Duster w/3 spd stick and 3.23 rear non-posi. Got a 4 spd and a 4.56 sure grip, and it was amazingly quick. My friends were dumbfounded when i took them for a ride. It was a rocket!
BUT, funny thing at the track, the times were NO BETTER!
sold 4spd and 4.56 the next day.
probably was only 40. that is my point about steep gears. it makes you THINK it is really fast, but it is just an illusion. Long time ago, I track drag raced a 318 Duster w/3 spd stick and 3.23 rear non-posi. Got a 4 spd and a 4.56 sure grip, and it was amazingly quick. My friends were dumbfounded when i took them for a ride. It was a rocket!
BUT, funny thing at the track, the times were NO BETTER!
sold 4spd and 4.56 the next day.
Last edited by Matt Gruber; Jan 16, 2013 at 10:49 AM.
Race Director
Joined: Oct 2000
Posts: 15,065
Likes: 79
From: central FL, near the beach.
Well, you guys certainly sound knowledgeable, but a hydraulic lifter has a spring below the pushrod cup that can compress to avoid lifter noise, wouldn't the hydraulic lifter spring compress when the lifter first starts riding up the cam lobe and the valve stay where it is until the slack is taken up in the lifter spring? In other words, with a hydraulic cam, how can the valve start moving as soon as the lifter hits the start of the ramp?
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
The op is well over 300 FWHP and 350 ft lbs with his present setup. A cam swap will not improve on that much without heads or head modifications and other upgrades. If you move the powerband up the resulting decrease in lower rpm power is not what he is looking for. If more seat of the pants acceleration is the objective a lower gear differential is the solution. It is no harder to drive. Fuel mileage will decrease. Crusing RPM will increase. It will feel noticably quicker. Price you pay.
Race Director
Joined: Oct 2000
Posts: 15,065
Likes: 79
From: central FL, near the beach.
The op is well over 300 FWHP and 350 ft lbs with his present setup. A cam swap will not improve on that much without heads or head modifications and other upgrades. If you move the powerband up the resulting decrease in lower rpm power is not what he is looking for. If more seat of the pants acceleration is the objective a lower gear differential is the solution. It is no harder to drive. Fuel mileage will decrease. Crusing RPM will increase. It will feel noticably quicker. Price you pay.
BUT, it sometimes did not spin the tires. Then in 2007 i put in the 4holer and shut off 1 unneeded carb passage. All this talk about TM, but mako doesn't believe what i'm doing really works. What a shame
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Isn't there a small hole in the middle of the side of the lifter to allow oil to escape?
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Race Director
Joined: Oct 2000
Posts: 15,065
Likes: 79
From: central FL, near the beach.
i started with a 265 56 chevy.
then a 283. They were fun to drive with their stock cams.
a 350 has massive torque by comparison. Guys put the wrong cam in a 350, and think they need a 383. With the right cam/setup they usually don't. Talking about real street cars, not drag cars with slicks. I don't see the point of say, 500 hp, if my street tires are maxed out at ~375. I always chuckle at the high HP guys complaining about wheelspin, even at 60 or 100mph. Those guys wasted $$$$$ on power they can't use. A shame. And despite all that "HP", often it is still a dog off the line without a steep gear/high stall. I have to apply throttle very slowly so as not to spin the tires. Otherwise my tires won't last 3,000 miles. That's with a 3.08 and stock stall, 2100.
then a 283. They were fun to drive with their stock cams.
a 350 has massive torque by comparison. Guys put the wrong cam in a 350, and think they need a 383. With the right cam/setup they usually don't. Talking about real street cars, not drag cars with slicks. I don't see the point of say, 500 hp, if my street tires are maxed out at ~375. I always chuckle at the high HP guys complaining about wheelspin, even at 60 or 100mph. Those guys wasted $$$$$ on power they can't use. A shame. And despite all that "HP", often it is still a dog off the line without a steep gear/high stall. I have to apply throttle very slowly so as not to spin the tires. Otherwise my tires won't last 3,000 miles. That's with a 3.08 and stock stall, 2100.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
The 260 rwhp and 309 torque were measured at the rear wheels. taking into acount the power required to turn transmission, ring and pinion your car would be producin roughly 300 hp and 350 ft lbs of torque at the flywheel which is pretty good.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
i started with a 265 56 chevy.
then a 283. They were fun to drive with their stock cams.
a 350 has massive torque by comparison. Guys put the wrong cam in a 350, and think they need a 383. With the right cam/setup they usually don't. Talking about real street cars, not drag cars with slicks. I don't see the point of say, 500 hp, if my street tires are maxed out at ~375. I always chuckle at the high HP guys complaining about wheelspin, even at 60 or 100mph. Those guys wasted $$$$$ on power they can't use. A shame. And despite all that "HP", often it is still a dog off the line without a steep gear/high stall. I have to apply throttle very slowly so as not to spin the tires. Otherwise my tires won't last 3,000 miles. That's with a 3.08 and stock stall, 2100.
then a 283. They were fun to drive with their stock cams.
a 350 has massive torque by comparison. Guys put the wrong cam in a 350, and think they need a 383. With the right cam/setup they usually don't. Talking about real street cars, not drag cars with slicks. I don't see the point of say, 500 hp, if my street tires are maxed out at ~375. I always chuckle at the high HP guys complaining about wheelspin, even at 60 or 100mph. Those guys wasted $$$$$ on power they can't use. A shame. And despite all that "HP", often it is still a dog off the line without a steep gear/high stall. I have to apply throttle very slowly so as not to spin the tires. Otherwise my tires won't last 3,000 miles. That's with a 3.08 and stock stall, 2100.
Though, I'm not going to knock on the guys with the big power builds... if they enjoy it let 'em to it.
Race Director
Joined: Oct 2000
Posts: 15,065
Likes: 79
From: central FL, near the beach.
Lots of guys with big power do go to the drags, with slicks, and it is a great hobby. 
They just forgot, or never knew how to harness the great torque of a 350 on the street. Then they give bogus advice to street only guys like: NEED GEARS, NEED STROKER NEED HIGH STALL, NEED ROLLER CAM, etc. It just sends them down the wrong path FOR THEIR INTENDED USE.
They just forgot, or never knew how to harness the great torque of a 350 on the street. Then they give bogus advice to street only guys like: NEED GEARS, NEED STROKER NEED HIGH STALL, NEED ROLLER CAM, etc. It just sends them down the wrong path FOR THEIR INTENDED USE.
Melting Slicks
Joined: Aug 2012
Posts: 2,548
Likes: 379
From: Woodinville WA
The op is well over 300 FWHP and 350 ft lbs with his present setup. A cam swap will not improve on that much without heads or head modifications and other upgrades. If you move the powerband up the resulting decrease in lower rpm power is not what he is looking for. If more seat of the pants acceleration is the objective a lower gear differential is the solution. It is no harder to drive. Fuel mileage will decrease. Crusing RPM will increase. It will feel noticably quicker. Price you pay.
I tried the low gear ratio idea in a 06 GTO. It went from nearly impossible to launch in 1st gear, to impossible in 1st and 2nd, and sluggish in 3rd (3.46 to 3.91)....
and I'm still sticking with my opinion - he doesn't have enough cam for the combo -
Melting Slicks
Joined: Aug 2012
Posts: 2,548
Likes: 379
From: Woodinville WA
Super BuickGuy
probably was only 40. that is my point about steep gears. it makes you THINK it is really fast, but it is just an illusion. Long time ago, I track drag raced a 318 Duster w/3 spd stick and 3.23 rear non-posi. Got a 4 spd and a 4.56 sure grip, and it was amazingly quick. My friends were dumbfounded when i took them for a ride. It was a rocket!
BUT, funny thing at the track, the times were NO BETTER!
sold 4spd and 4.56 the next day.
probably was only 40. that is my point about steep gears. it makes you THINK it is really fast, but it is just an illusion. Long time ago, I track drag raced a 318 Duster w/3 spd stick and 3.23 rear non-posi. Got a 4 spd and a 4.56 sure grip, and it was amazingly quick. My friends were dumbfounded when i took them for a ride. It was a rocket!
BUT, funny thing at the track, the times were NO BETTER!
sold 4spd and 4.56 the next day.
that was a good guesstimate about the final gear ratio - it calculates to 6.1:1 in low range.
Melting Slicks
Joined: Aug 2012
Posts: 2,548
Likes: 379
From: Woodinville WA
Lots of guys with big power do go to the drags, with slicks, and it is a great hobby. They just forgot, or never knew how to harness the great torque of a 350 on the street. Then they give bogus advice to street only guys like: NEED GEARS, NEED STROKER NEED HIGH STALL, NEED ROLLER CAM, etc. It just sends them down the wrong path FOR THEIR INTENDED USE.
They just forgot, or never knew how to harness the great torque of a 350 on the street. Then they give bogus advice to street only guys like: NEED GEARS, NEED STROKER NEED HIGH STALL, NEED ROLLER CAM, etc. It just sends them down the wrong path FOR THEIR INTENDED USE.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Well, you guys certainly sound knowledgeable, but a hydraulic lifter has a spring below the pushrod cup that can compress to avoid lifter noise, wouldn't the hydraulic lifter spring compress when the lifter first starts riding up the cam lobe and the valve stay where it is until the slack is taken up in the lifter spring? In other words, with a hydraulic cam, how can the valve start moving as soon as the lifter hits the start of the ramp?
I'm not trying to be a B, but how can the valve start opening as soon as the lifter hits the start of the ramp when there is a spring in the hydraulic lifter, a moveable cup holding the pushrod, and the oil in the lifter can escape through a bleed hole allowing the pushrod cup to lower in the lifter when it starts going up the ramp?
Melting Slicks
Joined: Aug 2012
Posts: 2,548
Likes: 379
From: Woodinville WA
It's the size of the hole that matters. The tiny hole can't possible let fluid out fast enough to allow compression of the lifter. Generally, the problem is just the opposite - valve float because the lifter pumps up
Another way to illustrate the principle.
A 'trick' to get a hydraulic lifter to act more like a solid lifter is to turn the adjust nut 1/8" turn from zero lash - then it can't pump up as much at high revs - the fluid doesn't rush out at high rpms, it gets trapped in the lifter at high rpms - which holds the valve open
Another way to illustrate the principle.
A 'trick' to get a hydraulic lifter to act more like a solid lifter is to turn the adjust nut 1/8" turn from zero lash - then it can't pump up as much at high revs - the fluid doesn't rush out at high rpms, it gets trapped in the lifter at high rpms - which holds the valve open
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
It's the size of the hole that matters. The tiny hole can't possible let fluid out fast enough to allow compression of the lifter. Generally, the problem is just the opposite - valve float because the lifter pumps up
Another way to illustrate the principle.
A 'trick' to get a hydraulic lifter to act more like a solid lifter is to turn the adjust nut 1/8" turn from zero lash - then it can't pump up as much at high revs - the fluid doesn't rush out at high rpms, it gets trapped in the lifter at high rpms - which holds the valve open
Another way to illustrate the principle.
A 'trick' to get a hydraulic lifter to act more like a solid lifter is to turn the adjust nut 1/8" turn from zero lash - then it can't pump up as much at high revs - the fluid doesn't rush out at high rpms, it gets trapped in the lifter at high rpms - which holds the valve open
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
I had a 345 scout with a dual range transfer case.
i'd put it in low range in 4x4, and it would LEAP. Top speed was 60mph, but it got there FAST.
that is like a 6:1 rear.
.
I think the long GM ramps are early Torque Management. TM is used on new cars to cut back low rpm torque and reduce warranty claims. So they used the long ramps in c3's to prevent burning the tires at every stop. They even slighty cut down the divider in some cars to further reduce torque. I've also seen iron intakes with passages connecting the 2 planes. What do you think that was for? TM! Sneaky, Huh!?
i'd put it in low range in 4x4, and it would LEAP. Top speed was 60mph, but it got there FAST.
that is like a 6:1 rear.
.
I think the long GM ramps are early Torque Management. TM is used on new cars to cut back low rpm torque and reduce warranty claims. So they used the long ramps in c3's to prevent burning the tires at every stop. They even slighty cut down the divider in some cars to further reduce torque. I've also seen iron intakes with passages connecting the 2 planes. What do you think that was for? TM! Sneaky, Huh!?
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
You can go with a modern camshaft, like the xe262h or the one below that. This would reduce the rpm range some, if you go smaller than the 262 youll loose top end power. You might try advancing your cam first, a cheaper attempt at a solution. If you wanted the same power with a lower rpm range youd need better heads. You could change the gear ratio to multiply torque a little more and get you into the rpm range quicker.