Advice for an OD trans for a 455

[Red78Calais4speed]

I have a 1979 Hurst/Olds that I put a mildly built 455 in 12 years ago. (The car had a non-original Olds 350/Turbo 350 combo so I wasn't worried about numbers-matching.) I also swapped in an 8.5" rear with 3.73 posi at the same time, but kept the Turbo 350 transmission and a Hughes 2500 stall converter. I don't drive the car on long trips because of the gearing. I'd like to swap in an OD transmission, preferably a 200 R4. I have one out of a 1987 442 (KZF code) sitting in my basement now. Should I consider having it beefed up or just sell it to buy one already done. Who reliably builds the 200 R4 to handle the power of a big block? I need an OD to be able to enjoy the car more. It's a fun car but only when I'm doing things locally. Since I swapped in this power train combo I only drive the car about 700 miles a year or less. 8-10 mpg just doesn't cut it anymore.
Plus, what do you think the engine is making for power? It is a 455 that is .030 over, Edelbrock aluminum heads out of the box (no porting), 10 to 1 compression, Comp Cams Xtreme energy 274H cam, roller rockers, Edelbrock Performer intake, Edelbrock 770 cfm carb, and stock "W" and "Z" cast iron exhaust manifolds into a 2.25 in true dual exhaust. The machine shop that built it for me guesstimated about 350 HP and 475 FT/LBS.
Think that's accurate? I need an OD transmission that will be reliable. I don't plan on taking it to the track but I can't rule out the occasional street shenanigans. Any advice would be appreciated.

 

[olds307 and 403]

You should have way more power than that. I would think 400 HP/500 ft/lbs isn't unreasonable even with 2.25" exhaust, I would upgrade to 2.5". CK Performance, Extreme Automatic among others build high torque 2004R. Go to CK Performance site and you can see what upgrades are needed at what power levels under competition components. A billet forward drum, hardened sun shell, stator, shift kit, servo and deep pan are all needed.

 

[lilbowtie]

That's a lot of work to go through to save $100.00 a year in fuel not to mention the $2000.00 your probably going to have in the trans and converter. Ever think of changing the gear??

 

[Bar50]

Put a replacement Turbo Buick (like 2200 stall) converter in it and slap it in. D5 originally. I will check, it may be a B29 Dacco...

I bet you would be just as happy with a 3.42 gear with the 455, but, it will go. The 442 200-4R has a govenor for 3.73 anyway.

Just be certain you have the geometry corrector for the carb and a good cable bracket TV cable has to be right.

 

[Red78Calais4speed]

I've thought about changing the gears, possibly to a 3.23. I feel that 3.73's are way too much gear for an Olds motor that makes a ton of torque. The only reason I went with the 3.73's was because the day I went to my local salvage yard to look for some other misc parts, they had just brought a white 1985 442 into the yard that morning. I saw it had the 8.5" rear and posi so I asked the guy at the counter about it. He said I could have the complete rear for $200 (that was in 2000). I couldn't get the money out of my pocket fast enough! Within 40 minutes, the rear end was in the trunk of my 1996 Buick Roadmaster sedan. (Damn, I miss that car. Awesome ride!)
Before the rear end change in my Hurst, I used to drive the car about 3,000 miles a year. I drove it every time I could and everywhere I could. Then I swapped in the 455 and the rear end. It was still a fun car, but a little too much to deal with on the highway for extended rides. I drove it less and less and only used it for short, local trips. I want to get back into using it more. I think it's been neglected too long.
I will definitely check out CK Performance and Extreme Automatic and see what they have to offer. Do they require a core to return or do you just buy a transmission outright? If not, I have a good running 1987 KZF trans to sell.

 

[oldsofb]

I'm with lilbowtie. Just spend the extra on gas and it will prob be cheaper in the long run. You could go the Gear Vendors route. You would spend another $700, but have a bullet proof OD. http://www.gearvendors.com/buy-now....TAILHOUSING&submit.x=13&submit.y=11&submit=GO

I would say spend the money on something else. I would keep the 3.73's too

Hutch

 

[thepcsurgeon]

I have blown 3 transmission's already (Wait, that did not sound right). Here is my secret. B&M Race TH400 Manual transmission, Gear Vendors unit( drops 700rpm when engaged), Ford 9 inch rear with 3.50 gears. My motor is a 502 making to the rear wheels, 564 HP and 785 ft. lbs. torque. I did kill a sprague in this transmission with less than 300 miles. Had it replaced and I have had no driveline issues since. I do make 12MPG on average unless my foot gets heavy. In that case, 3-5MPG. But my 502 is also FAST EZ-EFI 2.0 fuel injected.
My point is, if it's a couple of MPG increase you're looking for, you will have to drop some big coin to get there. If you plan on a wicked nasty street beast AND better MPG, it's going to cost some cash. HTH
Your motor makes more then they're reporting to you. 350HP is very low. A ZZ4 makes more than that. You need some dyno time to get the real numbers.

 

[Red78Calais4speed]

Sounds like changing gears might be the better (and cheaper) solution. Still like the idea of 3.23's. 3.08's may be too tall and 3.42's are only a step down from what I have. Plus, I can upgrade to a better posi unit. With the torque of the 455 I can't imagine I'd lose much in the way of acceleration with the 3.23's. The car still has the stock rims with 205/70R14 tires. I currently turn 3200 to 3400 rpm on the highway at about 65 or so mph.

 

[Texas82GP]

I would put a built 200-4R in it if it were mine. I'm an overdrive man. I'm ditching my four speed for a five speed.

 

[565bbchevy]

To me overdrive is the best of both worlds in a street car, I have a 200r4 in my Regal and if I blow that up I will be replacing it with a built one and someday I will put a GearVenders in the Monte since that is probably the strongest and least expensive route for that car.