Guest Orange Flame 72 Posted July 25, 2007 Share Posted July 25, 2007 I was swapping over the parts from my old TH350 to my new TCI TH350. I need to replace the dipstick tube and have one on order, but also found that the speedometer gear housings are not the same size. My old TH350 has a large (2"-3") opening where the new TH350 has a small (1") housing on the tailshaft. I simply swapped the old tailshaft (only 4 bolts) & speedo gears onto the new TH350 - had to get a new bushing & seal pressed in at the local trans shop...Not a huge deal, but got me thinking about the originality of the TH350 that came out of my Monte. I read somewhere that the larger speedometer gear housing is on Non-Chevy TH350s, and the Chevy TH350 has the smaller housing. Is it possible that the TH350 in my Monte is from another GM Make/Model? Confused... Quote Link to comment Share on other sites More sharing options...
montefrazer Posted July 25, 2007 Share Posted July 25, 2007 Is it possible that the TH350 in my Monte is from another GM Make/Model? Confused... Possible but not likely. Buick, Oldsmobile, and Pontiac had a different bolt pattern and won't bolt on a Chevy block. They also have the starter on the drivers side, not the passenger side like a Chevy. The possible exception is some trannys were made with dual bolt patterns and would fit Chevy or BOP blocks. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted July 25, 2007 Share Posted July 25, 2007 If somebody changed rear end gears and tried to get the spedometer reading correctly, they might have swapped out the chevy tailhousing for a BOP one because of the different speedo gears available. You can get a BOP/Chevy transmission that bolts up to either block, but they look a little different since they have extra bolt holes on the bell housing. My guess is just that somebody changed out the tailhousing. Quote Link to comment Share on other sites More sharing options...
Guest Orange Flame 72 Posted July 25, 2007 Share Posted July 25, 2007 Good - Thanks So the Chevy tail housing should have the smaller speedo gear opening and BOP has the larger? I just thought it was strange to see right after I read the info on TCIs website, and after finding all kinds of strange stuff on a car that was "never really worked on" according to the original owner... On the same note, how are the parking brake cables positioned on the trans cross-member? Mine has one cable going over it, and one cable going under it. Strange for a trans that was never removed, right? ...Thanks again for the info, Guys Quote Link to comment Share on other sites More sharing options...
1972mc Posted October 29, 2007 Share Posted October 29, 2007 Scott, ran into your July post and looked up your cardomain page. I see that you got the same blueprint engine I got. How is your's running? Have you taken it to the strip? What rear gear are you running? What about your carb and exhaust manifold? I am in the middle of a frame off on my 72 monte and just did the cam burn in this weekend. I still have the body off the frame, so I used a remote starter switch and temporary wiring. Ran pretty good, but would not idle without partially holding throttle or connecting vacuum advance. Am usinf a holley 750 vac advance and hi po GM HEI. Noticed after removing cast iron exhaust to install hedman ceramic coated header that #8 valve was very soot free and had gas in opening and in plug. Do you think this was normal due to no load on engine. Always had fouling problems on my old 350 in #8 cylinder. Carl Quote Link to comment Share on other sites More sharing options...
Guest Orange Flame 72 Posted December 16, 2007 Share Posted December 16, 2007 Sorry I am just replying to this post now. I have not been on the site for some time... Sadly, my 383 is not running yet. Been busy with other stuff. I am working on it over the winter to have the car on the street in the spring. I am using a Holley Avenger 770, MSD HEI, $180 Summit 1 5/8" Ceramic coated long headers (prety nice actually). How long did you run the engine? Did it have a chance to reach proper temperature? Does it sound lumpy? That would be cool...Let me know the details of how the engine ran. I need some sort of hope that my 383 will run at some point Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.