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Ok I'm new hear so we well c how this goes my truck is a 1980 20r with a 4 speed I'm about to have the motor rebuilt and I'm trying to figure out what to do about the transmission going down the highway at 55 it runs at like 3200 rpm's is this bad or can the transmission handle that kind of abuse what can I do to get it to run a little lower can I change the gears in the transmission or in the differential also anyone got any ideas for some mild performance upgrades for that old tired 20r for wen I have it rebuild it already has a webber and a header
Usually people would change the differential or the gears to run at lower rpms. Can you go up hills now without downshifting? My '81 probably has the same tranny and I have 3.90 gears in my differentials. But I haul stuff up hills so I wouldn't want higher gears.
I don't think 3200 rpms hurts anything except maybe gas mileage. Do you have a tachometer?
Oh: taller tires has the effect of raising your gear ratio. I have 32" tires and generally drive about 60 mph on open roads. I don't have a tach but it isn't over-revved.
I do have some problems with steep long hills at hwy speed if I am already doing 55 or 60 wen I start climbing I can hold on to fourth but if I start out on o hill wen I shift from 3rd to 4th it sucks it bogs down starts pinging I assume it is the valves pinging but I'm not really sure who ever put the weber on and did the de smogging did a half as job they didn't put a fuel pressure regulator on and they did not put a block off plate wear the egr goes on the head and there is one more thing they didn't do that I don't no what it is but I'm sure it needs to be removed and have a block off plate I'll include pix maby u can tell me what it is
Ok I finally got a fuel pressure regulator and gage and it seems to have helped but I can't seem to get the full pressure dyled in I set it to 2.5 thin go for a drive and check it and it has dropped or risen any apinon or segestions would be helpful
You need 5psi minimum to run a carb, better still 7psi for the long pull. You have a fuel pump problem or you lines are pinched. I would suggest moving up to 3/8 from 5/16 and new filter.
I finally got some carburetor cleaner to check for vacuum leek and of course that dam two piece redline adapter leeks so after some thought I ordered a one piece adapter I got the trans adapt 2120 I figured it was a good time so I ordered a rebuild /tune up kit for the weber 32 36 now I'm no carburetor mechanic so this will be my first one but after some research I thank I got it now I'm just waiting for parts in the mean time iv got the carburetor off pulled apart cleaned and took notes of the jet sizes and air tubs lots of pix any questions or comments are appreciated
Just after I got it out <br ><br >
if truck has stock gears its 4.375's 3200rpm is normal at speed. it can handle it; transmission, and engine. 79 and 80's are geared lower. you could put some 4.10's in it if you want to get the rpm's down some, but if you are running 31" tires are larger or plan on 31's or larger I'd keep the 4.38's. Carb looks good so far make a note of your jet sizes while your in there and where they are/were. I'm running that trans adapt plate too its a nice piece.
05-25-2016, 06:55 AM
