Speedmaster billet planetary 727 gear set.

[TIMINATOR]

Has anyone had any experience with the Speedmaster billet planetary gearsets? They are 5 and 6 pinion straight cut 8620 steel and look good. Are they a standard ratio? They gotta be better than the stock stuff.?
PCE 550-1010
I'm building a street, occasional strip 512 raised runner headed solid roller motor that will have some squeeze on it eventually.
Nobody even knows if they are stock ratio.
Thanks for any info!
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[GTX JOHN]

I run the stock stuff in my 512 9 second Bracket Duster for
10 years and no problem.

I do not trust Speedmaster

I use straight cuts and custom ratios in my Stock/Superstock cars
and get them from ProTrans in Waco Texas = I have for 30 years.

 

[TIMINATOR]

How much stall, trans brake? With stock stuff in your 727?
I am a retired machineshop owner (40+ years), and have extensively used and installed heads, manifolds, alum radiators, fuel cells, rocker covers, roller rockers,, and more, from Pro Comp/Speedmaster during their time in business.
The only failures were three roller rockers from a set that were sold over the counter. The customer never told us the application or we would have recommended a race quality Comp Cams set instead.
The Street rockers that failed after 2 1/2 + years were installed in a 1955 Chevy Bel Air with a 383 CNC aluminum headed street/strip car with 3.70 gears and 2800 stall convertor that ran mid 11s. They were 1.6 ratio street series rockers on a Comp Cams .592/.598 lift Hyd. Roller cam, regularly shifting at 6200+. He thought they should be warrantied! That was the only failure that I am aware of.
We don't sell their studs or bolts, only ARP, and some of their distributors have a really poorly designed advance system that is very hard to curve. We do sell their distributors for locked out race or H.P. street use though.
The funny thing is that a LOT of folks that say they would never run Speedmaster "junk", but buy it in a "house brand" from SEVERAL major retailers!
My deal is, I have never sold any brands at my shop that I have not run the items in my own street/strip or racecars first.
My 512 has: 1/2" stroker crank, 7.1" rods, heads, intake, aluminum water pump housing, alum water pump, starter, roller rockers, rocker covers, and valley pan, among other parts from Speedmaster.
The straight cut 5 and 6 pinion planetaries and billet drum kit is probably not because I need it, but because I will find out if it will live behind a tran braked, TCI 4500 stall, aluminum headed, solid roller cammed 512 on drag radials.
I'll let ya know!
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[Tig]

You should be OK. Once we got past 850hp n/a we seemed to highlight the weak areas in the drivetrain. I've upgraded to steel planetaries after tearing the splines out, std ratio, think it was an A and A piece. The car is heavy (4023lb w/d), footbraked and the bigger of the 2 engines makes well over 1000 h/p and 950 lb/ft N/A but we've broken the upgraded Dana 60 and 727 several times, even with the smaller 900+hp N/A engine. The 727 is surviving OK so far but has just about everything upgraded internally now. Talking to the experts (I'm not one) there are a few design issues with the 727 that prevents it being upgraded further to handle high H/P and Tq, a weak (ish) case and a small bell housing necessitating a narrow and therefore weaker converter being a couple.
We're putting a 500hp fogger kit on the big engine so I'm going to have to go to a 9" derived rear and an aftermarket TH type 'box before pressing the button. At a potential 1700+ hp and the N2O tq to match I've been recommended to go to a 'glide or Rossler 3 speed by a couple 727 specialists.

 

[TIMINATOR]

Thanks for the great feedback TIG!
Mine is a lot calmer than your setups, but I will keep in mind everything you said. My Challenger is predominatly a street car that will only go to the track a few times. I expect it will run 9.80s or so on the motor, but it only has a bar and is only legal to ten flat.
I'll tune it as close as possible with a wideband and Draggy on the street and drive it to the track to see what it does. My standard deal with the last few street cars is do some good launches and back off on the big end to stay in the high 10s. Then when I am comfortable, I'll make a full pass and get kicked out.
Then in about a month I'll come back and "hit the plate."
My goal is to run 9s N/A and whatever on the bottle. Bragging rights ya know....
It has P/S, P/B, A/C, P/W, quiet mufflers, and a full interior with roll bar. It's just a weekend cruiser and for the weekly car show nights. I'm sick of looking at gutted 5.0 moostangs and shoebox Novas that run 10s that are popular here.
THANKS AGAIN FOR THE INSIGHTS!
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[Tig]

We had to make around 800hp before we broke into the 9's and go over 137 but the car is heavy. We picked up over a 1/10th and a lot more consistancy by just switching to a radial slick. Car has run 9.51 @ 142 and some change. 1.29 60ft best but normally it's mid to hi 1.30's on the rear wheels. We ran the big engine for a while but had some issues. that went a best of 9.46 @ 145.9 with a poor 60ft of 1.49 we chased a bog for a few meeting before pulling the motor and discovering stuff. All things fixed it would easy go lo 9's but we have rebuilt and upgraded and it made a lot more H/P on the dyno BUT we don't race dyno's. The timing tickets will tell.

 

[TIMINATOR]

Well... My 1972 Chevelle ran 10.80 @124+ with P/S, P/B, A/C, 3.73 gears and an off the shelf Hughes 3000 stall convertor at 3660 lbs (w/d) thru the mufflers on Hoosier 295/50 street treaded tires with a stock stroke, iron OVAL (ported) port 454 at 10.9 compression, Comp Cams 262/.651 solid street roller cam. I built it in 1988 and It was my daily driver and only car for over 3 years. I ran it most Friday nite drags. With a plate system it regularly ran "greasy-all- over-the- lane" low 9.90s@ 134. In 1988!
I machined and built the motor and modified the rear suspension. It solid hooked on the motor, but I couldn't hit the plate till near the 60' lites. I don't remember the 60's, but they were dismal.
The iron oval port heads only flowed around 270 cfm and that's why the fastest carburetor (head flow limited) was an 800 dp on a Dart single plane intake. Horsepower calculated to lo/mid 500 range.
I have 9 sec hopes for the Challenger since it's lighter, has 4.10 gears, 4200 TCI, trans brake, 275/50 R code drag radials and my custom spec leaf springs with relocated front spring eye mounts, subframe connectors. Not to mention 512" w/TFS raised runner and ported heads, a bigger roller cam, HP 950 holley, and 7.1" rods as opposed to the 6.135" of the chebbie.
I expect around high 600+ HP numbers. I have learned a LOT since 1988. Since I still own my own HP machineshop I believe this is doable. I will not quit until I get a 9 sec. time slip thru the muffs. Then whatever it runs with the plate.Time will tell.
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