There's a simple formula for figuring out the 1/4 mile et/mph from the cars weight and hp.
It shows 410hp & around 3700lbs (heavy race wt.)will give you a potential 11.60@113, but this is if the car is set up for the 1/4 and hooks well.
If not you should still be able to run some low-mid 12s at around 110mph.

 

67RS502,

Thanks for the reply. Where can I get my hands on that formula? Does the formual take gearing into account? I am just trying to figure out what I will gain in performance and time with the 5 speed and gearing change.

Thanks again,

Victor

 

The formula has been around since the 60s, the Mopar book has it, I use the Moroso slide ruler (power speed calculator), but like I said it give the "potential" for a well set up car, so it doesnt take any chassis set up into consideration. Its just the laws of physics, wt. distance, mph & hp. Also if youre gonna go with a Tremec, you wont need a lot of gear, since the trans has a 3.27 1st gear.

 

67RS502,

That is funny, I never thought of it as a physics problem, but thats exactly what it is. Thanks for the insight, I was making it a lot more complicated than I needed it to be.

In reality it does get complicated with all of the friction losses but for what I was looking for the simple physics problem is perfect.

Thanks again

Just curious, what is that 502 putting out HP and Torque wise?


Victor

 

Go to prestage.com and look for the formulas section. Their's are based on HP at the wheels. Figure 10-20% loss through the drive line

 

Thanks for the info Greg.

What part of North Carolina are you in?.


Victor

 

Yes, it is all physics. You can go to a 4.XX gear using a 3-series carrier, use a thick ring gear style.

 

Prestage formula is WRONG - it gives the flywheel HP not rwhp, those
late model morons always screw things up!
The 502 made 625hp/627tq, (610hp with the alt. and water pump hooked up),
with 2" dyno headers & no exhaust.
And at 3300lbs race wt. the formula is right on, imagine that!
Physics are still the same today as back in the 60s, well for
all accept the late model crowd, I guess they have to make an extra 100hp
or so to run the same times as we do

(Use mph when figuring the hp, as et can very)

 

Obxhokie,

I am about 8 hours west in Winston Salem.

 

Originally posted by Obxhokie:


(P.S) Any body know if they make bolt on sub frame connectors for a convertible?

Yes, they are available, but I forget who makes them. If you post this question in the "convertibles" section you'll get an answer.

PS They hang awfully low because of the body bracing on the floor pan of the convert.

 

Are you thinking of Global West??

 

Yes, Global West is the one. Thanks, Paul.

 

Al & Paul,

Thanks for the insight on the subframe connectors. I will post over in convertibles and see if some has a picture to show how low they hang. I am running full length headers, are the SFC's lowere that the collector flange on those? Anyway hopefully I can get a picture of them. Al, How do you like that ZZ 383 engine? If it is the one I am thinking of thats the motor I am trying to pattern mine after.

67RS502,

Thanks for the heads up on the Prestage formula I was thinking the mph and time looked slow. I guess they use it for justification for using the giggle gas.

Greg, Thanks for the link. Even though the formula was off, there is a lot of other interesting info there. I haven't been to Winston Salem in a long time, but I am pretty familiar with it. I do get pretty close to there twice a year for the Martinsville races.

 

Al,

I did a search on Global West Sub Frame Connectors in the vert section. Jrager's thread was perfect for info and had a good picture of the SFC's. They do look a little low and are a little too noticable for me. Are you Running SFC's? I am trying to see if I can get away from using them and still run 400 to 425 HP.

Maybe someone will come along with a more stealth SFC later on. I want a bolt on that doesn't hang down so it is really noticable. I am restoring my vert is to look as stock as possible on the outside and interior, with modern technology beefed up internals such as the stroker engine, A TKO 5 speed, 4 wheel power discs, etc.

 

Bolt-ons will hang down a bit

I'll post back on the ZZ383 tomorrow in more detail - but for now I love it!

DS&E makes a very nice weld-in connector. I am running totally stock suspension but looking to upgrade over the winter.

TTYL

 

Al,

I saw your post on your engine and cam upgrade. Are you looking for more high RPM power? What are your 1/4 or 1/8 times now? Anyway, looking forward to the 383 info and I will be following your cam thread with interest.

Thanks again for your help.

Victor

 

On the ZZ383...

Mine isn't exactly what GM sells, but it is very similar. They use a 4.00" bore and a 3.8" stroke, where I am using the more common 4.030" bore and 3.75" stroke. I doubt it makes much diff.

The cam in the ZZ383 is a .509/.528 220/230 112 (I think) where the Hot cam is .525/.525 218/228 112. Again, very similar. The ZZ383 doesn't come with an intake - I'm using the GM dual plane which is made by Edelbrock and is a Performer RPM with the hot water crossover added. Both engines use the Fastburn heads.

My engine is nothing more than a bored and stroked ZZ430 with a slightly stouter bottom end. It runs fabulously well and I really have no complaints. I have just read a few articles on the xr282hr in a 383 and it sounds like an excellent cam for a street motor. Also, Gary from GMPP stated in a post on the Sallee website that a 383 can really come alive with a bit mor cam that the hot cam. But as I said, I really love this motor as is. My car is a convert and it's iffy as to whether I'll ever drag race it (I'd like to try) - my guess is that with traction and some tuning it could run around 12.0

I'm probably going to pull the engine this winter to fix a pan gasket leak, and thought I might as well try the xr282hr.

Cheers!!


PS Here is Gary at GMPP's post cut and pasted from the Sallee site.

Fast burn heads and a HOT cam on a 383 with flat top pistons (9.5 to 1 cr), dual plane intake and 750cfm mechanical carb will make about 440HP at 5800 rpm, but the torque curve is awsome flat with well over 400 ft.lbs. over much of the range. We just completed testing on an engine like this. Demon carb made 10 more HP than a Holley, $1000 Braswell made another 10 over the Demon. Single plane intake made no more peak HP and torque fell about 10-20 throughout the range. The HOT cam is a little small on a 383 due to the bore/stroke relationship and the difficulty with cylinder fill with the longer stroke. A little bigger cam and a little bit of valve job/cylinder head work wakes the combo up big time with power in the 470-500 range, and the torque curve is still flat.
In terms of FB385 vs. 383, a 383 will make a little more power (20 to 30 HP) and they have a flatter torque curve. But it's harder to make that power because the bore/stroke relationship is more "truck-like." If you think about a pro-stock engine, they are large bore short stroke and so they have very good cylinder fill characteristics. And subsequently rev higher before running out of breath than a smaller bore longer stroke engine with all else being equal. My personal opinion, I like a good 350 or 355 over a 383 for a light street machine with alot of converter and rear axle gear and a 383(or a big block) for a heavier "cruiser" without alot of gear and converter....but that's just me.A ZZ430 (FB385 w/HOT cam), zero decked with a little clean-up in bowls and a "tuned-up" valve job will make 450+HP at 6000rpm and it's a ball to drive with 3500 converter, 28" tires and 4.11 gear in a 3000 car.

 

Al,

Thanks for the info, and all of your help. Between your engine info and your paste of Gary's info I pretty much have all of my questions on the 383 answered. I always assumed I would build another 350 until I started reading up on the 383.

I think the 383 is better suited for a street cruiser that maybe sees a little track, (dragstrip time.) I used to love to do the road race thing but there are no tracks do do that anywhere near where I am, and the closest strip is over an hour away. So I don't need to spin the motor 6000+ rpm with a close ratio tranny to keep it in the prime power band like a road racer does or a more serious strip racer. I think the 383 with a very broad torque cuve and good HP numbers at 5 to 5.5 k is what I want
to push around my heavy @#$ vert, with a 3.08 posi rear and a M20. Later I'll swtich to a TKO 600 and change the rear gears. but I still wont be spinning any higher.

Al, thanks again for the help. I joined this March after lurking on the site since before I bought the car last September. There is a wealth of knowledge on this site that I have searched, and everyone has been so helpful with my posts. Great site, great people, who lend advice and aren't afraid to debate an issue, or two.

Thanks again

Victor

 

Thanks, Victor. This site IS the best....

As a reinforcement to what you said, I had this ZZ430 as both a 350 and a 383....while both were excellent, the 383 is without question more powerful. Here is some good reading, and another reason I'm considering the xr282hr.....

http://www.hotrod.com/techarticles/66278/index.html

http://www.chevyhiperformance.com/techarticles/57841/

Cheers,

Al