my 1984 monte carlo ss has a 350 and a 3 speed out of an 88 el camino... problem is the car wont go faster than 50mph without red lining... tranny and motor fully rebuilt with less than 3k on both... has aftermarket b&m starshifter in it... was told it has a drag rearend in it... anyone have any advice on how to fix or what might be wrong...

 

Thats your problem, a 3 speed. You probably have the stock rear end (3.42:1) if its the stock 84. you might have 3:73's in the back. I dont understand if its stock because with the stock 3 speed and 3.42:1 gears your rpm's should be 3000 at 65mph. Otherwise the timing might just be off.

 

are you getting into all 3 gears? when mine was running i think my readline was 50 in first!

what is the trans? th350? th200? depeding on the year of elky it was taken out of it may have a tourq converter lock up that wasn't made to work when they made the swap,

did they remove the computer? if so what kind of carb does it have on it and did they replace the orginal one with a vac advance dist?

 

Rearend is not stock bt origins unknown... Im runnin 6k rpm at 50 mph... Motor is the 350 frm 75 monte... Tranny is a compatable mv4 from 88 el camino... Btw non diesel 350 guys... If that helps...

 

Edelbrock performer intake and edelbrock 4 barrel carb with electronic choke. Ive been told that the tranny was a compatible swap for the non diesel 350...

 

Emnasty are u saying my issue may be caused by the possibility that the rearend is for the stock diesel? Ran vin and it registers a 350, bt 84 was a diesel with the th200r4... Which is a 4 speed tranny...

 

The rearend probably has really tall gears. If it was described as a "drag" rear end it probably has at least 4.10s but as fast as it redlines, its probably in the mid to high 4.xx range. Put the car in neutral and jack the back end up. Rotate the rear wheel and count how many times the driveshaft turns. For example, if the driveshaft turns 4 1/2 times for 1 revolution of the rear wheel, then the rearend ratio is 4.50:1. The higher the number, the taller the gears and your engine has to spin at a higher RPM to get up to speed. If you lower the ratio then your car will drive down the road at a lower RPM.

 

i just researched for like 2 hrs and found that the rear end doesnt look like its ever even been unbolted... so that must mean its the stock limited slip with 3.42:1. stock motor was a 305... im now runnin a 350... any advice?

 

Did you check the rear ratio anyway?

 

even if it was 4.10s he shouldnt be spinning that hard at 50. when i first swapped in the 3.73 ss rear into my car with the factory cam 400 i could keep up on the highway 60 70 and not be spinning 6k. im with bud on this one first thing would be to insure that you are actually getting into 3rd. i dont remember what the second gear ratio is in the 350 but its got to be like 1.7, or somewhere in that ballpark. 3rd is a 1.1. this might sound like a stupid question, but you dont have a full manual reverse valve body do you? if you do then that would explain a lot. when you put the car in drive it would go into 1st and wouldnt shift unless you shifted down into second and down again into 3rd. idk know if you were to run a standard full manual valve body what would happen when you shifted directly to drive. if it would only run in 3rd. i would assume so, but ive never had one that was full manual, or reverse pattern. just manual auto. you can try shifting by hand to see what happens. i also agree that you should attempt to find out your approximate gear ratio. all the housings look the same and youll never know if they swapped out the carrier and gears.