It started w/Drop Base Air Filters.
Seeing as I was leaving some HP on the table, got me to thinking.
My 218-224 w/1.6RRs, AG, TFS heads and 2' RHs.
Puts out 300 rwhp and 330 rwtq.
Long ago the forum posted 300 rwhp for 160mph and 600 rwhp for 200mph.
Not sure if I can believe that?
I would like to get into the 12s and hit 160n in a mile?
I like my cam, but some CNC porting should give me more than a few HP!
MY TFS heads are 500 hp heads at best.
What would CNC porting and headers give me?
Enough for 12s and 160 on top?
TIA
R

 

This calculator will get you in the “ballpark” for figuring out your HP numbers.

https://www.gofastmath.com/Horsepowe...wer-Calculator

 

Some of the Pros here on the forum have said my current set up should be good for about 13.2 in the 1/4.
I would like to know how much I would gain from mods.
If AFR 190cc heads would produce an extra 30 rwhp as some have claimed.
Would porting and headers give me an extra 40 rwhp?
How much faster would that make me?

 

430HP will get you into the 12's around 108 to 115 mph with good tires before anything should break. With that HP you can tear teeth off your diff and rip the rear snubber apart...IVe done both and at that level with my 327. My best was 13 flat at 108mph spinning my tires in the first 3 gears.....I couldnt launch to save my life. 108 mph should be right around 12.5. My cams were above 250 duration and .510 lift on 93 octane with 3.70 gears. I did eventually go to a 427 BBC and 4.11s but havent been able to get it on the track

 

I am well aware of how much strain drag racing puts on a car.
For years I have read about HP breaking parts.
I have never dropped the clutch on my 3;55 gears.
I know extra traction strains on the trans and rear end and breaks things.
I was thinking of making A 12 sec run for bragging rights. No more!
A top speed test shouldn't be as much strain.
My engine peaks @ 5600.

 

Hp and torque cross at 5252 and hp generally is highest at higher RPM so you will be accelerating through your torque and shifting just as you get into the HP power band......Torque gets you up to speed fast, HP keeps you there. Do you have an automatic? If you have a clutch you are going to want to go higher into the rpm because everytime you shift you will be falling down to 3000 rpm. With that low of a max rpm I would believe you have a big block engine, if not you will want a different cam for your goal either way you will be into 4rth gear pretty quick shifting at 5600 rpm

You dont need to drop your clutch to get up to speed but you will need to feather your clutch and get to max rpm as fast as possible to reach your goal for 12 seconds. As for max speed a rolling start wont hurt your drivetrain as bad as a launch but when you get over 500 ft/lbs just the torque of driving normal will tear up a transmission. I tore my first 5 speed up that was rated for 400 ftlbs by sticking it behind my 427

 

Nitrous is by far the easiest, most cost effective, most fun way to achieve your goals.
go order a 125 shot WET SHOT kit off summit and have fun. If you’re making 300 at the wheels the 125 shot will land you mid 12s easy

 

It may take more than one run to get that elusive 12 second time slip. Nothing humbles a man like a disappointing time slip!

 

Or Six Sacks, 2 interceptions, a fumble and the worst half time there ever was....!

​​​​​​​60

 

Too bad the refs got the memo not to interfere by Roger Goodell after his interview where he stated that the refs never decide the game.....then had to be reminded 4 plays into the game.... then had to be reminded a few more times as the game wore on. IF the refs were able to help then the Chiefs might have won

 

​​​​​​​I was watching reruns of Bob's Burgers.

 

My engine has 300 rwtq @ 3000 rpm.
It pulls very hard!
My M21 trans close ratio is a waste and will be replaced by a 5 sp.

 

I love that show!

 

Going fast with a later model Corvette might be more challenging and very expensive. The early C3's were made with higher horsepower engine and have some of the important power parts that later C3's didn't come with.

To be able to go fast and break into the 12's will be a lot harder and far more expensive than you might imagine. I built a copy of an L88 and I enjoy the immense horsepower but like Rescue Rogers mentioned getting traction can be a real challenge. My 427 will spin the rear tires way past the 1/8th mile mark while trying to go. The only way for me was to launch gently and roll the power on slowly and it will turn a 12 second or faster quarter mile easily.

The M-21 transmission, drive shaft, differential and half shafts are all highly stressed when you launch hard. I would like to start with the transmission, the bevel cut gears push "outwards" when they are loaded up so switching to a set of Straight Cut gears and make your transmission into a "rock crusher" and reduce the side loading inside the gearbox. Then you need to remove any U-joints that have any grease fitting on them. I have solid u-joints everywhere on my C3. My differential came with Blocks to secure the u-joints instead of the little wire cap. Since the car was built for a 427 it has several parts that were beefed up from the factory.

My old Gtech Pro was a great tool as it gave me data that helped me fix my problems before Air/Fuel meters. I weighed the car and entered the weight into the Gtech Pro which then could tell me if the new part made power and how much or it showed that the new part was a loss. I did 0-60 mph runs as that was convenient for me and it would tell me right away when the car was faster and how much horsepower it was making. This one tool was invaluable to make the car faster and it even has Shift lights on it.

I don't know about the 1977 Corvettes but the 1968 C3 feels like the front end is taking off like an aircraft at above 120-125 mph unless you do some serious aerodynamic work on the front. I used a pace car front spoiler and that certainly helped as it kept the nose from lifting up.

 

Thanks to everyone for the info.
I would still like to know how much HP porting and headers would give me?
And how fast that would go?

R

 

have you tried as is?
Getting the clutch release just right is vital for a solid 60 foot.

I think you’d be best off hitting a few test runs and then you’ll know how much power(if any) you’ll need to add. Headers worth maybe 15ish hp? If you end up being 13.1-13.2 that’s maybe all you’ll need.

Also, tires are very important for drag racing. You can have a 500 horse motor and not being able to run a 12 if you’re on hard crappy street tires.

Everyone’s first trip to the drag strip is always humbling lol just FYI

 

I just got my 74 back on the road.
Scared to break it so soon. lol
I haven't run the car for a time.
It spins them hard in 2nd.
I'm trying to keep my car a "Parts bin special' where ever possible.
I understand that big tires go fast and break parts.
I'm going to A 5 SP, I would like to avoid a rear end and driveline upgrades?
If I go over say 350 rwhp w/big tires, I will break **** for sure.
I will have to wait and see.

Thanks

 

Here is some data from my experience with my 77.

I had my Vortec heads pocket ported and picked up 2 tenths in the quarter mile.
When I originally put some runs on the car I had stock exh manifolds, 2.5 inch dual exhaust (no cats) and stock type mufflers. I changed to 1 5/8 primary, long tube headers and Magnaflow mufflers. The car picked up 4 tenths from that. A very significant change.

What rear gear is in your car? Is the diff original from 1974?

 

Some one from C&D wrote when testing the LT1, it sucked w/M21 trans.
They had to use 3:70 gears before the tires hooked.
I believe they ran low 13s?
My 3:55 is perfect for my engine, but M21 has to go.
it should get a good price?
Supposedly it came from a 69 camaro?
I will check.

 

I NEVER trust C&D for truthful and independent reporting.

A good friend had a 1970 LT1 and it had the M-21 and it worked great with that beautiful engine and it was an awesome Corvette to drive. That combination was powerful and in the hands of a good driver it was quite formidable. That engine made some serious HP for a SB from the factory.

Spend the money and buy the five speed transmission and it will still blow the differential to pieces. Either the differential or the half shafts will break next and after spending thousands of dollars on performance parts. In the end you will forego the independent rear suspension and have to go with a solid rear axle and a huge Ford rear end.

It is expensive to make any Corvette go REAL fast. The faster it goes on the track, the less you will be able to drive it on the roads as easily or safely. There is something as TOO MUCH Horsepower....