My 350 turbo which has been previously rebuilt will not stop leaking from the shift linkage and I'm starting to loose way too much fluid than I care for. My options are to rebuild the same tranny again and re bore the linkage hole from the inside out or rebuild build another 350 core. I was wondering if at this point I might as well switch to an overdrive tranny if its not cost prohibitive. I'm currently running a 350 with a 284 cam and other mods along with a B&M shift kit, stall converter and 3.08 gears with 14" tires so I'm curious about the pros and cons. What would be the best combo? I was thinking of going to 15's but want to keep the wheels so they can be rotated. Most of my driving is around town and I want some bite off the line but I still do higway driving now and then. Any ideas??
If I were converting to an overdrive transmission like the 2004R, I'd certainly want to make sure that it was built to withstand the power level of my engine, and the street/strip performance that I would demand of it. That and a good torque converter will cost you a lot more than a rebuild on the common THM350. So the question really is, can you afford it, and if so, does the fact that it might take a while to pay for itself (better gas mileage) bother you?
Thats exactly my concern at the moment. One way or another the tranny needs attention. I don't know enough about the overdrives which is why Iposted my concerns and thoughts. I want performance more than gas mileage as mycar is not an everyday driver but since I'm going to absorb the expense of arebuild one way or another I thought I'd explore my options. I guess my mainquestion is, can I get performance out an overdrive tranny or will it be costprohibitive for what I am looking for?<o></o>
All you need to do to answer that question is to call a rebuilder and get a quote on building each transmission. See the cost difference and you can decide. The 2004R has a 2.74 first gear vs. the 2.52 of the THM350. That gets you performance right there. The .67 overdrive gets you MPG , and reduction in RPM. Racing the car with a 2004R? Leave it in Drive instead of OD. You can have the same or better performance out of the 2004R, but it will cost more to beef it up and make it reliable. Find out the costs and decide.
I say go for the 2004R, and at your power level 350 I would just find a good working trans and swap it in without a rebuild. I found a 88 Caddy with a 2004R for $200, and I drove it for a long time and eventually will pull the trans and use it in my 75 Regal without a rebuild as it works great! I got a best of 26 MPG with my big old caddy and that was with a 2.42 gear so the car revved REALLY low even going 100 MPH LOL. Not quick off the line till we installed the nitrous! Regarding the tire diameter and gearing, if you were to use the 3.08 with your stock tire size and the overdrive trans you will get very good fuel mileage on the highway! If you go to a taller tire you will still be ok due to the fact that the 1st gear is better on the 2004R as Larry points out. An ideal ratio for a taller tire would be a 3.42 or 3.73 if you race however if it is a street car then the 3.08 is great.
Looks like I'll be going with the 200r4 as Ive been told my 350s days are numbered. If I can get a good 200r4 tranny that would be great but if I can't I'll buy a rebuildable core and do a performance rebuild if there is such a thing. I was told the only real concern with the swap will be shortening my driveshaft. There's a local shop that gets rave reviews as to having no balance issues. If I have the funds left I'd like to get an OEM 15" wheel set up to replace my 14" to get a beefier look.
Steve... save your penny's...Go for a manual coversion... 5 speed! http://americanpowertrain.com/i-852...a-body-lemans-gto-cutlass-442-skylark-gs.html ProFit TKO Installation Kit for 1968-74 Gen 2 BOP A-body (LeMans, GTO, Cutlass, 442, Skylark, GS) SKU: PFGM-20011P Pricing: $3145.00 American Powertrain Pro-Fit TKO kit for Gen 2 BOP A-Body for factory 4-speed cars. This kit uses your stock 4-speed bell housing. Note: You need to will select a clutch plate to match the splines for the TREMEC. You can reuse you stock flywheel and pressure plate. Or call us to help you select a complete clutch package. For Automatic conversion to manual please give us a call so we can custom build your kit. Kit includes: Transmission Streamlining - For a great, no cut/low cut fit in your tunnel AP Revolution Shifter Mechanism - Original 4-speed shift position Seamless DOM Driveshaft Assembly - Race Balanced, Solid U-Joints Driveshaft Slip Yoke - Cryogenically hardened steel Transmission Mount - Polyurethane Pilot Bearing - Stainless rollers, grease pre-pak Reverse Light Harness - Weatherseal Speedometer Conversion - Mechanical or Electronic Shifter Knob Console Shift Pattern Plate Hardware, Instructions, Warranty and Customer First 24-Hour Support Transmission sold separately
That kit assumes you have a manual already, but they do kits for conversion too, closer to $4k for the auto to manual conversion
Some 200r4 questions. 1. Can I re use my recently installed 350 torque converter? 2. Will the 200r4 benefit from a shift kit upgrade? 4. Are there certain year 200r4's to avoid?
No you can not use the th350 converter, however it should be easy to sell if it is a good one. One of the best parts about the 2004R swap is that you can get a lockup torque converter that gives you 100% lockup on the highway. In my truck I have a 3500 stall converter so the truck just launches off the line and on the highway I lock the converter with a toggle switch and enjoy 100% lockup and 22 MPG. In general the later the year 2004R the better. The trans from the SS Monte Carlos and Turbo Regals are the best but any trans can be built to be as good or better. YOu may or may not have to have the driveshaft modified to work. There is aonly about a 3/8" difference in length of the two trans. Yes, the 2004R can benefit from a shift kit. Contact Ken at Everday Performance for some tips on this swap and on a 2004R build if you go that route... :TU: I do not think he is building trans anymore for people however he might make an exception if you tell him Sean sent you.
No problem, and be sure to PM me when it is time to hook up the lockup wiring and I can talk you through it.
Sean, Any ideas on where to look for the lock up converter you refer to? Would the converter that comes standard with the 200r4 serve my needs?
I have had great luck with these low cost converters for a mild application like yours. Typically when you buy a converter only the $500+ units give you the stall speed you want and also a nice tight feel on the street without a bunch of slip. This is where the lockup style converters are superior as you get the stall you want and 100% lockup with the flip of a switch. I just love the 3000 stall converter in my truck and it is great to be able to get 100% lockup when ever I want. The stock converter is OK however to take advantage of your 284 cam you would really like a higher stall. For your combo I suggest this converter in a 2800 stall: http://www.revmaxconverters.com/index.php/torque-converters/car-torque-converters/2004r.html
Sean, As usual you have been a great help. I want to do this swap right the first time!! Thanks Steve
