Need some advice

Texas_85

n00b
Aug 11, 2020
4
3
Finally got a lift in my garage so I can start getting my 85 cutlass back together. I currently have a new 383 ready to by put in. I want to do this thing right this time and hoping I can get some advice on what transmission and rear end j should put in this build. Car will not be a daily driver, something that I can take out every so often for a cruise and be able to take it to the track and have some fun in. I was originally thinking of a th350 but now thinking a 700r4 might be the way to go with a ford 9” in the rear…. Looking for any input. Built a chevelle when I was 18 and thing was a slug because I didn’t know how to pair things up properly so this time around I want to get everything I can as far as hp/tq is concerned
 
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ck80

Comic Book Super Hero
Feb 18, 2014
4,547
113
Finally got a lift in my garage so I can start getting my 85 cutlass back together. I currently have a new 383 ready to by put in. I want to do this thing right this time and hoping I can get some advice on what transmission and rear end j should put in this build. Car will not be a daily driver, something that I can take out every so often for a cruise and be able to take it to the track and have some fun in. I was originally thinking of a th350 but now thinking a 700r4 might be the way to go with a ford 9” in the rear…. Looking for any input. Built a chevelle when I was 18 and thing was a slug because I didn’t know how to pair things up properly so this time around I want to get everything I can as far as hp/tq is concerned
Well, you're on the right track with your questions on 'pairing' to get the most oomph.

You say you have a 383... is it something you bought or built? Curious because wondering if you have a dyno sheet or if someone else may have a similar engine where we can tell what your power bands look like.

Once you've got that info, next question is your rin/tire combo, and how/where you plan to do most of your driving. In town off the line 0-50mph or lots of highway.

Then you add your transmission choice, and, you can use a calculator to pick your rear gearing so that at the given desired mph ranges you're hitting the right spots in your power band.

 
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melloelky

Comic Book Super Hero
Oct 22, 2017
3,767
113
mass
he's rite^^with the motor done build the rest of the combo around that.converter,intake.gearing,tire size are all relative.get a few options from company's on what to run and make your selection from there.example not all converters are created equal.i polled three companies and made my decision from there.
 
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scoti

Royal Smart Person
Supporting Member
Sep 5, 2019
1,639
113
Texas
If it's just an occasional use (sunny Sat/Sun) type of ride, a built OD trans will yield little return on investment as far as usage. How much highway driving do you anticipate?

Spending money on a better TH350 or TH400 would be smarter if the vehicle see's track time vs. extended highway jaunts. Match the converter to the cams range & then match the gearing to the converter.

TH350/TH400's have better gearing ratios vs. the 700-r4.

The 200-4r is similar to a TH350 but w/OD. Harder to find vs. the 700-r4 but it should be considered if thinking about automatic OD transmissions.
 
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scoti

Royal Smart Person
Supporting Member
Sep 5, 2019
1,639
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Texas
Nobody mentioned the 4L80e yet - you'd need something like this to make the electronic trans work: https://www.summitracing.com/parts/tci-302820
I didn't mention it because of the high cost. I figured it might be worth mentioning if he responds w/the need for an OD set-up if he plans on accumulating highway miles on his weekend jaunts.

Building a 4l80e isn't cheap. A decent converter for one is definitely not cheap. Since most 383's are likely carb'd, it didn't seem worth mentioning the 4l60e/4l80e options because of the added cost for controlling the trans.
 
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doood

Amateur Mechanic
Sep 24, 2020
260
93
I didn't mention it because of the high cost. I figured it might be worth mentioning if he responds w/the need for an OD set-up if he plans on accumulating highway miles on his weekend jaunts.

Building a 4l80e isn't cheap. A decent converter for one is definitely not cheap. Since most 383's are likely carb'd, it didn't seem worth mentioning the 4l60e/4l80e options because of the added cost for controlling the trans.
Since the guy has a 9-inch rear, the 700-R4 would be the weak link. Considering he just bought a lift he might have the $700 for the transmission controller. Three speeds are worthless if he wants to take it on the highway and he wants to have a good rear gear. If it was my car, I'd put a 4L80e with the controller, or would have kept the 7.5" if I had to go easy on the 700r4.
 

scoti

Royal Smart Person
Supporting Member
Sep 5, 2019
1,639
113
Texas
Since the guy has a 9-inch rear, the 700-R4 would be the weak link. Considering he just bought a lift he might have the $700 for the transmission controller. Three speeds are worthless if he wants to take it on the highway and he wants to have a good rear gear.
I agree. I wouldn't purchase one to use.
Not sure he actually has a 9" though since his statement mentioned:

Finally got a lift in my garage so I can start getting my 85 cutlass back together. I currently have a new 383 ready to by put in. I want to do this thing right this time and hoping I can get some advice on what transmission and rear end j should put in this build. Car will not be a daily driver, something that I can take out every so often for a cruise and be able to take it to the track and have some fun in. I was originally thinking of a th350 but now thinking a 700r4 might be the way to go with a ford 9” in the rear…. Looking for any input. Built a chevelle when I was 18 and thing was a slug because I didn’t know how to pair things up properly so this time around I want to get everything I can as far as hp/tq is concerned
It can be interpreted as a 700r4/9" combo he was thinking of purchasing vs he has a Ford 9" already.
 
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86LK

Royal Smart Person
Jul 23, 2018
1,078
113
If it's just an occasional use (sunny Sat/Sun) type of ride, a built OD trans will yield little return on investment as far as usage. How much highway driving do you anticipate?

Spending money on a better TH350 or TH400 would be smarter if the vehicle see's track time vs. extended highway jaunts. Match the converter to the cams range & then match the gearing to the converter.

TH350/TH400's have better gearing ratios vs. the 700-r4.

The 200-4r is similar to a TH350 but w/OD. Harder to find vs. the 700-r4 but it should be considered if thinking about automatic OD transmissions.
interesting because I know there is not that much that you can change in the system. I currently have a 305 with 200-4r in my 86. I recently got lucky finding an 8.5" rear from a member here. I do have plans to put a 383 in it eventually (block in the garage) and it would be a mixed usage, highway city driver. where would I find an explanation on finding the right converter for the plan?
 

scoti

Royal Smart Person
Supporting Member
Sep 5, 2019
1,639
113
Texas
interesting because I know there is not that much that you can change in the system. I currently have a 305 with 200-4r in my 86. I recently got lucky finding an 8.5" rear from a member here. I do have plans to put a 383 in it eventually (block in the garage) and it would be a mixed usage, highway city driver. where would I find an explanation on finding the right converter for the plan?
I'm not sure what you mean by "in the system"?

The converter needs to match the cam profile & rpm needs of the cam/heads combo to be most effective. If you have a stock converter but a cam w/>240° duration & 210cc heads you'd be leaving a lot on the table performance wise. Same would be true if you had a 3500 stall speed w/a stock cam/heads/<3.0 geared rear end w/>26" tires. The combo needs to compliment each other.
 
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