I am in the middle of changing to 400 turbo in 442. Ithas the factory 3.73 rear end now. I have been told that my rpm will be high at hi way speeds. What would a better gear to mate with this? Currently has a 403 turning between 350 and 400 horse.
442 transmission change
- Thread starter olds4ever
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3.08's may be a good gear. My 403 seemed to have endless low end torque regardless of what cam I put in it so I think your move makes sense. Why not use the factory 200-4R? The 4 speed is what makes the 4-4-2
Yeah, WAY better off sticking to the 2004r. A th400 is a very poor choice here. Please reconsider. You got a 442. Don't bugger it all up by shoehorning in an old dinosaur transmission.
Since you are commited to this. You want 2.41 gears if the goal is a highway cruiser... Because 3.73 x .67 = 2.49
You may be able to put a 2.73 gear set on the stock 3-series carrier; but, 3.08s are more readily available and a direct swap. A 2-series 8.5" carrier might be available for some truck applications.
Just so we are clear you gave up OD to go much slower all over the rev range. Your best bet is to get a stout torque converter to regain some of the holeshot you lost by lowering first gear and the rearend ratio.
You may be able to put a 2.73 gear set on the stock 3-series carrier; but, 3.08s are more readily available and a direct swap. A 2-series 8.5" carrier might be available for some truck applications.
Just so we are clear you gave up OD to go much slower all over the rev range. Your best bet is to get a stout torque converter to regain some of the holeshot you lost by lowering first gear and the rearend ratio.
OOF. Yeah, while the TH400 is a super-stout transmission, it's likely not a first choice for a semi-modern street car nowadays. It has its place, though, but likely not in an 80s 442. JMO.
Since you're in the middle of it as you say, you can elect maybe to go back to a "built" 4R or continue on with the conversion. A properly stiffened up 4R will cure your ills without all the extra work.
Unless there's something wrong with the 400 transmission, you'll NEVER tear that thing up with 350-400 HP. So that's a plus. But it's inefficient next to the 4R. It will waste more gas and then you're changing rear ends for what? The current set up with a beefed up 4R (many threads on this) and maybe some new U-joints and if it's still in good shape, the 8.5 back there should be able to handle anything from your 403 and still give you good grunt on bottom end and have nice cruising rpm to boot.
I'm not diss'ing your choices, but just wondering why go through all that change just to have a TH400? You'll need to do a little bit of console/shifter mods as well, so if you want to ever go back stock...= more work. In my experience if you're worried about higher RPM on the highway by swapping to a TH400, then you're doing it for the wrong reason. Again, JMO.
Since you're in the middle of it as you say, you can elect maybe to go back to a "built" 4R or continue on with the conversion. A properly stiffened up 4R will cure your ills without all the extra work.
Unless there's something wrong with the 400 transmission, you'll NEVER tear that thing up with 350-400 HP. So that's a plus. But it's inefficient next to the 4R. It will waste more gas and then you're changing rear ends for what? The current set up with a beefed up 4R (many threads on this) and maybe some new U-joints and if it's still in good shape, the 8.5 back there should be able to handle anything from your 403 and still give you good grunt on bottom end and have nice cruising rpm to boot.
I'm not diss'ing your choices, but just wondering why go through all that change just to have a TH400? You'll need to do a little bit of console/shifter mods as well, so if you want to ever go back stock...= more work. In my experience if you're worried about higher RPM on the highway by swapping to a TH400, then you're doing it for the wrong reason. Again, JMO.
I had a 74 GP with a TH400 and a 2.93 rear end. That was a decent gear for city and highway
Save the time and money on the swap and put it towards a stout 2004R. My biggest regret in my build is keeping the TH400. Its fun and its reliable but a 4L80E is better all around. I would recommend a 4L80E to you but you're not making that much power(no offense) so a mild 2004R should live. And keep some originality to the 4-4-2
And as an aside, there's some parts in a 4L80E that are the same as a TH400, like some shafts, bearings, bits and parts. Leads me to believe it's akin to an electronic TH400, or as close to it as you'll find. I'm not a transmission expert, but I do look at part numbers and cross-references, etc.
I motion to what the others have said about beefing up the 2004R. Swapping out the rear gears, modifying your driveshaft, changing out the crossmember to fit the th400 may not be as beneficial.
Out of curiosity why did you not choose a th350 since that would have been an easier swap?
Out of curiosity why did you not choose a th350 since that would have been an easier swap?
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