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I have an '81 Pontiac Firebird, 468 Olds, 224/[email protected]/2", .507" lift 110 LSA Hydraulic Roller cam, 1.6 Roller Rockers, Edlebrock Heads, Dual Plane , Edlebrock Air-Gap Manifold, 3:73 gears/positracton, 750 Holly HP, built TH350, B&M HoldShot 2500 Stall Speed, 28" tires, Hooker Long-Tube Competition Headers, MSD-6AL-2 & Distributor, 10.1 Forged Pistons, runs 11.3s @ 115 mph in the 1/4 mile.

Problem is that I blow up my TH350 about once every year to a year & a half. I have a B&M Shift kit in it and a heavy duty sprag with heavy duty disks and I don't know what else. It's been rebuilt through my Mechanic who built the engine, rear end, fixed my axels when I twisted them out of the 3rd member, and has been with me through 2 engines...... good mechanic but I don't alway get satisfactory answers.

Should I just buy a Hughes/B&M/TCI or Monster Transmission and have him install it for me? Looking for suggestions/HELP.... Jerry
 

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Install a T-400 transmission. 34 element sprag. Attention to detail as the trans is built, will work well.
 
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Discussion Starter #3
Install a T-400 transmission. 34 element sprag. Attention to detail as the trans is built, will work well.
I know that a TH400 is an answer but I hear they take more HP to operate them and I'm not interested in going slower. I don't have "that much HP already" so trying to keep what I have. Can't a TH350 be built for a 400 RWHP/430 RWTQ Oldsmobile in a 3200# Firebird that lasts longer?
 

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What spedifically happens when you "blow up the trans" every year?

Is it typically that you lose 2nd gear, blow up the roller clutch sprag and race? Becomes a second nuetral almost instantly?
if that's true, then...

You appear to be at the point power-wise and timeslip-wise that you need the aftermarket drum with the "dogbone style" 36 element intermediate sprag rather than the 8 element stock roller clutch on a stock drum with an added hardened race.
More than doubles the strength of second gear.
A hardened stock sprag race and HD clutches is not the answer....the stronger clutches just make it that much easier to pop the sprag race.
You should also have a heavy-duty Sun shell added.

We really need to know details as to exatly what heavy-duty mods your mechanic is supposedly making.

As far as shift kit goes, making the trans hit harder just breaks parts, it doesn't improve reliability. B&M isn't the best choice.
 
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Discussion Starter #5
What spedifically happens when you "blow up the trans" every year?

Is it typically that you lose 2nd gear, blow up the roller clutch sprag and race? Becomes a second nuetral almost instantly?
if that's true, then...

You appear to be at the point power-wise and timeslip-wise that you need the aftermarket drum with the "dogbone style" 36 element intermediate sprag rather than the 8 element stock roller clutch on a stock drum with an added hardened race.
More than doubles the strength of second gear.
A hardened stock sprag race and HD clutches is not the answer....the stronger clutches just make it that much easier to pop the sprag race.
You should also have a heavy-duty Sun shell added.

We really need to know details as to exatly what heavy-duty mods your mechanic is supposedly making.

As far as shift kit goes, making the trans hit harder just breaks parts, it doesn't improve reliability. B&M isn't the best choice.
I don't know what breaks but this time I Launched OK and shifted to second at 5800 rpm and a loud metallic "Bang" and no gears anywhere. No reverse, 1st, 2nd, or 3rd. I can't remember the other two times but the first time the Trans had over 500 runs between the previous owner and me... it was just "time" for that one to go down. The second time I had to send it back twice to meet my expectations shifting. I'll talk to my mechanic about what parts are failing and get back to the Forum - Thanks!
 

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Stop with the "the T-400 takes more power" thing... I doubt you will be slower. That CID of engine needs the T-400 or a very well built T-350 in a 3200 pound car. The strength difference of the T-400 over the T-350 for maybe 10-12 extra (real life, not internet life) Horse Power is a wise decision.

When the T-350 made a "bang" noise and stop all movement forward or reverse... Likely the input shaft broke out of the forward drum. Also possible the turbine hub inside the convertor broke since all vehicle movement stopped
 
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Discussion Starter #7
Has anybody had any experience with either the Mad Dog "The Godfather" TH350 Level 3 or the California Performance Transmission's Street/Strip TH350. These both say that they're the toughest TH350 in their category? CPT is close to my house so it's a "no freight" deal from them but it has to handle my engine/car at the Drags almost weekly - Jerry
 

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CPT is where Art Carr is now, you don't get much more experience in the industry than him. He is one of the pioneers.

I'd go with him way before Mad Dog.
 
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Discussion Starter #11
455Olds, what Drag Strip are you going to?
Something local, or are you traveling weekly?
I just started with the Summit Series #1 last week and every first Sunday at Irwindale, CA strip. Usually they've had a Test "n Tune Saturday the day before Before that it was once a month maybe twice. There's a Test "N Tune this weekend and the 21st then Summit #2 on 4/11. It's no Spectators and Two Crew people per car... Keeps the crowd in control. Must wear masks, Police have been on site every time I've been there......
 
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Discussion Starter #14
Cool, so they're just running 1/8 mile then I assume...
Yes they're running 1/8 mile as always. I can't wait until Fontana opens. I've been running 7.68x's currently with a slipping transmission but I should be running 7.3xx's. My 60' is 1.69x's and should be 1.60x with an occassional 1.5xx. If you don't make your 60' time you don't make the 7.3xx's. I expect that a updated Trans will solve that. Then it's up to me. - Jerry
 
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Discussion Starter #15
power glide ? or is this a street car?
No Powerglide. It's my daily driver and has a TH350 as noted above so, it's a "street car". I have a lot of fun playing with Corvettes, Mustangs, and other street "muscle cars". I don't street race, just play. There's enough "street legal drags" happening so why street race? Just invite them to Irwindale........ - Jerry
 
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Discussion Starter #18
CPT is where Art Carr is now, you don't get much more experience in the industry than him. He is one of the pioneers.

I'd go with him way before Mad Dog.
Eric, I met with Art Carr yesterday, what a nice guy, and we discussed using his modified 200R4 built for my engine (Drag Racing). He has a convincing argument. He can rebuild my TH350 to handle my engine but the price difference is about $500? The 200R4 is the same length as TH350 so no Drive Shaft change , has a lower 1st gear, and has overdrive. I've read to not "Power 4th" when drag racing or you'll have problems but that shouldn't matter with my setup. I'm considering this option. Anybody out there that has first hand experience?? - Jerry
 

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Yes they're running 1/8 mile as always. I can't wait until Fontana opens.
Not to be negative, but...
Have you been following the "news" regarding Fontana?

They're "reconfiguring" the Speedway...
On their drawing of the "proposal" to the county, it doesn't look like the area of the property with the Drag Strip (and backstretch of the speedway) is part of the plan at all.
Since they're shrinking the speedway down to 1/2 mile, it will fit within the current front-stretch to pit area of the infield, so the rumors are that everything beyond the garages will be sold off... which includes the Drag Strip.

I'm pretty pissed off, since I just replaced my entire drivetrain so that I could go to the Strip, since it's about 3 miles from my house...
Just as I was building my 383, the last piece of the puzzle, I found out that Nascar (who now owns the Speedway) had proposed this "reconfiguration".
F-ing figures...

If you run across any drag racers with ideas on how we might be able to keep the last 1/4 mile strip in So Cal, let us know...
I don't know if they're planning on opening the strip at all before the "reconfiguration". As of now it says "will remain closed" (due to COVID)... not "until", just "will remain".
 

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Eric, I met with Art Carr yesterday, what a nice guy, and we discussed using his modified 200R4 built for my engine (Drag Racing). He has a convincing argument. He can rebuild my TH350 to handle my engine but the price difference is about $500? The 200R4 is the same length as TH350 so no Drive Shaft change , has a lower 1st gear, and has overdrive. I've read to not "Power 4th" when drag racing or you'll have problems but that shouldn't matter with my setup. I'm considering this option. Anybody out there that has first hand experience?? - Jerry
Not personally with Art Carr parts, but I have used a well built 200-4R in a 383 powered '86 Monte Carlo SS, probably an honest 475 hp or so....trans was built fairly local to me, 50 mile drive, but he has since retired. Never had any trouble with it and the converter he built to go with it. Runs really well, but my freind has never taken it to the strip....this summer I think I'm going to tie a Dragy to him on a test hit ...LOL.
 
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