[avman]

I have been planning and working towards a 6XX HP and 650+Torque stroker big block build for my 70 Roadrunner. Yes, I know this is a Pontiac forum. Once Dick Boneske gets our 3 Rochesters and works his magic on reengineering them to work with the performance rebuild we did on the 421 Tripower in the 65 GTO, I will have completed ALL of the other updates and upgrades. The TKO600 5 speed is going to be one of the last things installed, but I've got it, and it's going to make the 3.80 ring and pinion gearset easier to live with on the highway in 5th, but 1st-4th are going to move it on out. Coilover rear conversion too.

Anyway, back on topic: What is it like driving, cruising, doing the "local" monthly car show thing and maybe one or two trips a month to the local drag strip for test and tune night, and pick up a race or two, maybe a friend or race track acquaintance who you tell "I've seen you run, and I think I can beat you, let's line 'em up" when you have 6XX HP and over 650 ft lbs of torque?
Throw in a manual transmission. A strong one, like a M-22 or any of the stronger aftermarket transmissions, but not "race only" manual transmissions.
I've heard a lot of negativity about pairing a manual transmission with that kind of power. My 5 speed in my Roadrunner is guaranteed to handle 700 continuous ft lbs of torque, and a number of people say that is a safe, conservative number.
So tell me, the good, bad, and best parts of your experiences with that kind of power in a street/strip car.
Thanks

[i82much]

My experience with 575 horsepower and a manual transmission is that I am scared ****less and will be lucky if I ever summon up the sack to take it to a dragstrip.

Car is 100% driveable though, cruising is no issue whatsoever. Traction breaks parts, street tires save parts.

[pokey1]

After rebuilding my 467 2 years ago I ran it the first year with the same M20 I had been running for many years previous. Motor putting out close to 500 hp and more torque ( at rear wheels) and was using drag radials was always nervous about tearing it up. It lasted first year than switched to T56 Magnum and lower geared 9". Ran the next year feeling more comfortable but still using only the drag radials. Last winter added FAST 2.0 and 150 shot of nitrous and put on slicks. It ran good with no issues but first gear was short and had to shift to 2nd quickly then able to go full throttle and activate the nitrous. This winter will have adjustable coil overs all the way around to improve weight transfer and plan to go with 2nd gear starts so I can roll into full throttle and nitrous right away. Hoping that will improve times a fair amount. Feeling pretty good about strength of tranny at this point. See how that works... than maybe even step up nitrous shot a little more

[avman]

Thanks for the reply, and LOL for your choice of how to describe it.
Yeah, the "traction breaking parts" thing is one of the recurring themes.
So as soon as possible, I am doing a complete upgrade of the rear suspension in my Roadrunner. Unlike you lucky ba$tards with our 65 GTO (A-body) as my learning palette, where our GTO has a "factory 4 link" my Roadrunner has 1890s technology, aka leaf springs. I bent the crap out of the mounting bracket (the main spine) of the best pinion snubber available on my first run and on the 2nd run, it bent so bad I had to remove it. THAT told me my rear leaf springs were worn out, and wrapping up. So I was going to toss the whole leaf springs setup and go with a triangulated 4 link and coilovers (much like I'm doing with the Quick Performance Ford based 9" rear axle assembly in the GTO) BUT I was talked out of it, and I'm going with Calvert mono split leaf springs, sliders, and Assassin traction bars. Viking double adjustable shocks on the rear, and I've already got those kind of shocks on the front.
Anyway, my plans for traction off the line include the HitMaster launch control system that is made by the same manufacturer as the ClutchTamer. I have been wanting a hydraulic throwout bearing, and I have a Hydramax T.O. bearing to install, and I'm expecting that HitMaster will prevent excessive wheelspin AND protect my weakest link. Between a chrome molly driveshaft I'm going to get, and the Dana 60 that came in my car, along with a 4.10 ring and pinion gearset, I think it's going to take a lot of force and maybe a big mistake on my part to break something.

[AG]

Why not run CalTracs with Calvert split mono leafs? I will putting a TKO behind a 700 Hp motor next year and I am going to get the gears cryo treated, REM polished, change the synchros to the carbon fiber type and use the brass shift fork tabs to prep the trans.

[avman]

I'm running the Calvert split mono leaf springs, and I was going to use the CalTracks traction bars, but I found the Assassin bars were a better made, more adjustable version. Same concept and function, just better.

[GTO Dan]

About 10 years ado Ran a 474” n/a with a solid roller that made 600hp/600tq at the crank on the street (not a DD but drove it a lot. Ran on the strip occasionally. Autogear M22 with a Centerforce DF clutch and 9” with 4.10s. Ran great, no real issues and very drivable. Now drivable varies by individual, it had an 8 pt cage and a Hurst RamRod (in-line shifter) for giggles.

Dedicated race.car and it’s a 535, GForce G5R ( get that if you have the coin) and McLeod adjustable clutch.

Keep banging them gears and have fun!

[GTOLou]

For your purpose - I think you are fine. TKO600 is supposed to be pretty strong.

I ran an autogear muncie behind my 474, 69 vert GTO and even went to a 535 - HR in low 250's. Shaker dominator. It was a solid motor - I NEVER really beat the crap out of my set up. Granny shifting. Maybe 3000 RPM soft launch.

My 12 bolt w/ forged axles held up. My autogear held up (have a 455 in car now). With 28, then 26 inch slicks, I spun a centerforce DF clutch. Went to a dual disc and that held great. My aftermarket driveshaft front yoke twisted the splines - better forged unit fixed that.


I think you're ok. You may break a clutch or yoke or something..lol. But a decent autogear or TKO 600, I bet, will be fine.