Hi Guys! I'm New to this site and have been lurking for a few days,Reading and trying to learn about the 3rd Gen body while waiting for my new project to arrive. I am wanting to get back into Racing after a 10 year absence. A friend called about a clean 87 RS project that his Chassis shop had started on and the P.O. lost interest in. I went and looked it over and deal was made for Car incompleted. It consists of a Clean Body with original redish maroon paint,Stripped down on the inside,No seats or carpet,No motor or trans.. New S&W Chromoly FAB9 Housing 2 inches narrower than stock with Strange aluminum center,Spool w/3.90 pro gear, Strange 35 spline pro axles,Strange disc brakes,Chromoly adjustable trailing arms,Chromoly Torgue Arm, Santuff D/A Coilovers,Has 10 point C/M cage and Sub frame connectors, The NOT so good, front is rolling but bone stock, It has a new AJE K-member for it. The "PLAN" I have a All Aluminum 565 with Dart 360's, Trans Brake PG from previous ride,and a shoe horn. The "Goal" make it Hook up on 29x10's? Any help with where to start lightening it up would be appreciated, crash bars, fiberglass,lexan, and so on....Thanks Ron

 

why a powerglide?

 

With his power the powerglide will be a good option


Sounds like a solid start. I've heard some not so nice things about aje. I'd get a Racecraft or Pa Racing k member/ a arms. What struts are up fro? With a little work the strange mustang struts can work.

I imagine hooking up on a 29.5x10.5 wouldn't be a hard task with what You have planned. Make sure to get a good anti-roll bar in it too

 

lot of hp in a light ride... I don't see a problem with a glide...

 

The 3.90 gears will mean a low rpm at the finish line. Even with 29" tires, they probably won't be deep enough. With the 1.76 (assumed) first gear in the powerglide, launches will be dead slow. 4.10, 4.56 or deeper gears would be better unless you plan on keeping the engine rpm below 6000 rpm which I highly doubt based on your current list of parts. No sense building an engine that makes power to at least 7500 rpm then restricting it to low rpms. If it was intended to be a street car, the Dart 360 heads would be far too big even for the 565. I ran some 310 heads on my 540 but it was running out of breathing room above 7000 rpm. The Dart 360 I have are heavily ported and still allow the engine to breathe at 7800 rpm.

35 spline axles for this combination will be a huge overkill. Without the deep torque multiplication of a 3 speed and deep gears in the diff, 35 spline is way too much which means a lot of extra unsprung weight. With my 4.86 gears, I can still get by with 31 spline axles but upgrading to 33 spline for me would be better. If a 3 speed transmission was being used or the car was 3500+ pounds then 35 spline would be optimal.

When I ran 29.5 x 10.5 slicks, I was using 4.56 gears. I was able to dip into the 9's. I back halved the car to get more rubber on the pavement for better traction so I could hook up easier on poor track conditions. It's always nice to say you can go fast on a small tire but with monster torque, a big tire is the way to go.

 

I see a problem with losing 30% torque at the line .

 

Well finally arrived back home from working out of town and the Toy is here. Started by giving the thing a good bath and sorting out the parts that were piled up in it.Most of the Engine parts and trans are what I have left over from previous racing operation.The chassis and rearend components will have to do for now and should provide a starting point or baseline and can make adjustments from there. As far as gears? Will probably leave them as is for now! Sent motor back to Nickens bros. to have it freshened up and still made 988hp and 806 tq....Trans is a A1 pro glide with 1.76 low and 5200 Chance converter, Will send it off and probably have it tightened up a bit....Now to decide on headers? Ed Quay or Dan Lemons? Hmmmm Will look into the AJE product a little more Thanks for the info

 

i dont think that you can go wrong with the ed quay headers or the Lemons headers. where did it make peak torque on the dyno? and we need pictures!!!!

 

an 87 RS huh? must be a special edition RS

and def need pics!

 

I'm actually a bit surprised that anyone would run 31spline axles in anything f-body like that needs a 9inch. It seems that you run out of torque capacity with 31's pretty quickly, last I looked there aren't many good parts choices for 33 spline (though it would be the sweet spot for most cars), so you end up with 35 by default...

I'm going to have 35 spline axles behind my 305 but I guess I'm special...

 

Using the old Moser axle calculator, axle size depends on the amount of torque you're putting to the axles.

Maximum engine torque x First gear ratio x Diff ratio x 0.9 = maximum torque to axles.

I'll do an estimate to say my engine is producing 850 pounds of torque but because I'm down on power from racing at altitude, I know it's actually lower.

850 x 1.76 x 4.86 x 0.9 = 6543 pounds

The Moser axle chart lists axles by pounds of strength. One axle should handle the total torque. An OEM axle is much weaker and other brands may have different limits. I had Strange axles once and didn't like them. The axle was thinner than the splines so the axle couldn't be shortened. Moser axles are the same diameter as the splines.

31 spline = 7000 pounds
33 spline = 8200
35 spline = 9600
40 spline = 12000

Now without knowing a lot more details about his 565, lets estimate he'll make around 800 pounds of torque.

800 x 1.76 x 3.90 x 0.9 = 4942
That's well below the requirement for 31 spline axles. If he decided to run a 3 speed tranny then 33 spline would be a minimum especially if he went with a deeper gear in the diff.

TH350
800 x 2.52 x 3.90 x 0.9 = 7076 - Just over the limits of 31 spline

TH400 (better choice)
800 x 2.48 x 3.90 x 0.9 = 6963 - Just under the limits of 31 spline
800 x 2.48 x 4.56 x 0.9 = 8142 - Slightly under the limits for 33 spline

One axle needs to be strong enough to handle all the torque. Any more than that and it's dead weight. When I first bought my axles, I painted a line down the length of them. Last year when I pulled my axles to install disk brakes, the splines and the line down the length were still straight.

Saying you have 35 or even 40 spline axles in your car when they don't need it is just bragging rights. He never mentioned anything about using a power adder which will increase the torque output of the engine which would be a good requirement for larger axles. A big NA BBC engine with a transbrake on a 10" tire will probably always get some sort of tire spin which will decrease the load on the axles anyway.

 

yea, I figured that it was pretty much working out because of the powerglide's very moderate first gear ratio.

What is the .9 in there? And shouldn't you factor in the converter's torque multiplication?

 

90% efficiency calculation.

 

my 31 spline axles are twisting behind a 350/th400 and some nitrous. lol

my suggestion to this build would also be to spray it and leave the gear in there.

 

OK,Bit the Bullet today and ordered Headers from Ed Quay! Funny think was they would not recommended a specific Primary ,or Collector size and suggested I get with Engine Builder! Well long story short, 2 1/4 tube and 4 1/2 diameter collector 12 inches long! They spent the time to answer any and probably too many questions.Have great customer service... Old Cam setup Max Horsepower was @ 7400 and Torque @ 6200..... .785 int and 750 exh....Not intended for street use...Heads are from RMS have 2.30/1.94 Titanium int and Inconel exh and Flow over 420 @.800 and are from My OLD Blower motor...Hoping the PG and 3.90 will help bleed of some torgue at Launch...Any way Headers will arrive in 10 days and will have Camera shots coming this weekend....

 

should be a solid setup, i 2nd the vote to hit that thing in the face with some juice

 

Hey im new to this also, however many thanks goes out to everyone! i have used this site for so much in the past year. I currently have an 89 rs 305 with mild mods...open element intake bigger throttle bodys 3.73 pro gears with posy. long tube headers with true dual flowmaster one chambers. Just curious on any ideas of other "cheap" as far as that goes....horsepower gains

thanks again to everyone!