Team Chevelle banner
1 - 8 of 8 Posts
G

·
Discussion Starter · #1 ·
My car is running a little sluggish since I converted to an M20. I still have a stock 10 bolt rearend with really tall gears, when I had a TH350 it hit the gears ok, definately hit far higher speeds. Im in 4th gear on the freeway at 3k RPM at 70mph, does that seem right? Also coming out of 1st gear unless I give it alot of gas it gets really shakey and jumpy... if I floor it I get alot of pops and backfires.... which sounds like a tuning issue, but when I had the automatic in I didnt get that? Strange, im slightly tempted to go back to an automatic Turbo 400 :)
 

·
Premium Member
Joined
·
9,525 Posts
Pop and backfire is an independant problem. Is the shake and jump clutch chatter? If so you need to resurface the flyweel and check the pressure plate. What combo did you go with. (I know it's not the bellhousing:noway: )
 

·
Premium Member
Joined
·
839 Posts
Phil,

Sorry if this seems insulting, but did you disconnect the vacuum modulator at the tranny when you removed the TH350 and forget to plug it at the carb? It is an easy thing to overlook.

Also, what rear gear are you running? If it is too tall (numerically low) like the stock 2.73, your 1st gear launch is going to be a bit of a challenge due to no longer having a torque converter. If I don't feather the clutch a bit, mine bucks like a bronco until I get moving a bit. (I have a 12-bolt that will be getting 3.73 gears sometime soon).

Lastly, what clutch and pressure plate are you using. Some people are tempted to use solid hubbed clutches instead of spring hubbed, and this can also cause a lot of chatter with a tall gear and manual.
 
G

·
Discussion Starter · #4 ·
Yeah the vacuum is blocked off, it idles great. Just when I really give it gas I have problems. The rear end I think is a 2.73 or so, stock 10 bolt... sad little rear end. The clutch and pressure plate are both the 454 Competition series Zoom, I know alot of guys dont like them but I couldnt afford the Mcleod or Centerforce.
 

·
Registered
Joined
·
251 Posts
check your dist cap that is the first thing to get knocked loose when you drop a tranny, happened to me:D

also what carb is on there now and what is the timing set at?
 
G

·
Discussion Starter · #7 ·
I think its the #1405 manual choke 750 edelbrock. I'll check the distributor for sure, Its mainly just since I switched over to a 4 speed from automatic. I played with the timing and readjusted the mixtures on the carb. I might take it appart this weekend and check the floats and clean it out and check my timing again...
 

·
Premium Member
Joined
·
839 Posts
Phil,

Is the carb a mechanical secondary? If so, that combined with your rearend gearing and the 4-speed could all be contributing to your problems. You have to remember that you no longer have a torque converter between the engine and trans, so no slipping and no additional torque multiplication like what you had with the auto tranny.

Also, do you know for certain that you have 3.08 gears? I would think 2 series of some kind for a stock automatic equipped non SS car.
 
1 - 8 of 8 Posts
Top