redhotskittle Posted February 25, 2012 Share Posted February 25, 2012 I am currently trying to buy a 280z with a 350 small block. has a few problems. 350 small block truck bottom 64cc angle plug heads small cam aluminum intake carb 780 vacuum secondary turbo 400 stock stock 1976 280z auto rear diff (3.54) rear tires are 225/70/14 apparently he saids the gear run out at 50?...he said is just the tires ....what could be reason behind this. I really want this car, but i need to figure out what is making this problem occur. thanks Quote Link to comment Share on other sites More sharing options...
Zinpieces Posted February 25, 2012 Share Posted February 25, 2012 Make sure it's not an 80's smog low compression RV motor. They made some torque but no horsepower. Carb sounds too big. Get the casting numbers from the block and the heads. motor could just be a dog. Rear, trans, and tire combo sound reasonable. Good luck. Quote Link to comment Share on other sites More sharing options...
redhotskittle Posted February 25, 2012 Author Share Posted February 25, 2012 i also done few top speed calculators and it says it should top out at 130-140 mph Quote Link to comment Share on other sites More sharing options...
redhotskittle Posted February 25, 2012 Author Share Posted February 25, 2012 he thinks the gearing is topping out at 50, i just dont see that happening.....what are some possibilities that maiking it not go pass 50? Quote Link to comment Share on other sites More sharing options...
jhm Posted February 25, 2012 Share Posted February 25, 2012 Have you driven it to see for yourself? As I'm sure you know, the TH400 (like the 350) is not an overdrive tranny....3rd gear is 1.0. Which SUCKS on the highway, especially when you've got a torquey motor in a light car, and could cruise along at 1800 rpm IF you only had the right gearing. Maybe that's what the current owner is referring to?? It's not the tires...225/70/14 gives you 26.4" rolling diameter....entirely within the range of acceptable. I guess another possibility is that the tranny is so thrashed that it's slipping horrendously? Quote Link to comment Share on other sites More sharing options...
redhotskittle Posted February 26, 2012 Author Share Posted February 26, 2012 yea i drove it...shifts fine. i didnt get it to 50, was in a neighborhood. so does it need a new trans, i have a 700r4 chillin in my garage. Quote Link to comment Share on other sites More sharing options...
jhm Posted February 26, 2012 Share Posted February 26, 2012 The 700-r4 and 200-4r are both very popular set-ups in the V8 Z's. Check out the "Drivetrain" sub-forum... P.S. If you're planning on mostly race duty (especially straight-line stuff), the 400 might be great for you. All depends on your specific application for the car. Good luck. Quote Link to comment Share on other sites More sharing options...
Rusty Bomb Posted March 20, 2012 Share Posted March 20, 2012 I just got my car and it was almost the same. 350 with turbo 350trans. Got up to 50 and petered out. Had the carb adjusted (my carb is bigger than yours) and I think it has some kind of rear end gearing. I do 2700 rpm and I'm not at 60 mph. Quote Link to comment Share on other sites More sharing options...
fastzcars Posted March 21, 2012 Share Posted March 21, 2012 It sounds like it's not shifting into 3rd gear. t400 is a 3 speed and top gear is 1.1 ! Id slap that 700r in and enjoy the overdrive. Quote Link to comment Share on other sites More sharing options...
Rusty Bomb Posted April 24, 2012 Share Posted April 24, 2012 Humm my setup sounds similar. I'm about 2700 rpm at 55-60 mph. Crazy gas mileage for sure. And I do hit 3rd gear. Quote Link to comment Share on other sites More sharing options...
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