Team Camaro Tech banner
1 - 20 of 22 Posts

·
Registered
Joined
·
55 Posts
Discussion Starter · #1 ·
Hey Guys,

68 with a 468BBC, stock heads, 800cfm Edlebrock, 3.73 posi-rear.

Currently using a built TH350, but I want highway manners. The final goal of the car is to be a fun/fast cruiser, never a strip car.

I just got my hands on a pull-out R700 that "works fine". I called my local tranny shop and they said for $2500 they can rebuild/bullet-proof it. I am not questioning their work (lots of locals use them all the time). What I am interested in, is the opinions on what TQ to use.

Lock-up/Stall???

Also, would/should I consider changing the rearend? I've done a million "what ifs" on the various online calculators.. I know one benefit of the 700 is that bigger 1st gear, which should mean I could get away with 3.55 or 3.08s out of the hole... keep in mind, NO TRACK.. but at the same time, I better be able to make a little bit of noise/smoke when I want to.

thoughts???

thanks in advance!

Matt
 

·
Registered
Joined
·
3,151 Posts
your BB makes good TQ and the 700 OD gear means you can go with a higher gear in the rear given your not drag racing and the 700 has a real low 1st

so it comes down to how fast, MPH, do you want to drive on Fwy for sustained periods and at what RPM
so enter various rear in gear ratios in a RPM calculator to see where you want to be

3:27 or 3:31 (assuming 8.8" rear end) may be what you want with a 2400 stall but IDK what cam you have and the cam/TC relationship is important

Once you decide on gear set up then pick TC stall or discuss with the trans builder....

I have now and have used Hughes TC in a few cars
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #3 ·
your BB makes good TQ and the 700 OD gear means you can go with a higher gear in the rear given your not drag racing and the 700 has a real low 1st

so it comes down to how fast, MPH, do you want to drive on Fwy for sustained periods and at what RPM
so enter various rear in gear ratios in a RPM calculator to see where you want to be

3:27 or 3:31 (assuming 8.8" rear end) may be what you want with a 2400 stall but IDK what cam you have and the cam/TC relationship is important

Once you decide on gear set up then pick TC stall or discuss with the trans builder....

I have now and have used Hughes TC in a few cars
hey SoCal, thanks.. I didn't build the motor so I don't know the cam... I really don't want to pull the heads to measure, but I am starting to think that I am going to have to. /sigh

the question on the stall is... I have read a little about using lock-ups on 700s in order to keep the pressure normalized. I will talk to the trans builder about that before I make my final decision.. this is me trying to crowdsource more things to be "smart" about so I can ask him meaningful questions. :)

So you are saying, pick my cruise speed/RPM, and reverse engineer from there? Obviously, powerband matters... Do you think it is necessary to get a true dyno? I feel like most BBC run fairly consistent powerbands... I am gut/guessing my output in the mid-high 400s...

Given this, I would like to cruise the highway in the lowish 2ks (2200ish) at around 75ish... I just rechecked the maths... 3.08 with .7 OD will do [email protected] is that going to lug the engine? Damn.. so much to consider! :)
 

·
Registered
Joined
·
3,151 Posts
My suggestion was to settle on rear gear first for what RPM you want at...75 mph as you note

Rear gear is also a factor in stall speed, as is weight of car, on TC but the cam/stall is more

Yeah with 3:08 and the low 1st gear of the 700 work well for a cruiser gear but still get the car moving but I doubt you will be cruising at 87 mph (2250 RPM) so the 3:31 may be the right match. Just put in that 411 in the RPM calculator you are using and decide. you have a BB so not a high RPM motor so cruising at 1800-2200 RPM at Fwy speeds is a good range

If you have more than 14" of manifold vacuum your cam is not to big so a 2200-2400 stall would be good and you should be able to do without a external trans cooler although they never hurt with higher stall TC. If you drag race I would suggest higher stall and keep the 3:73 but sounds like you want a cruiser and low Fwy RPM.

Ask your builder about a lock up TC for your trans . Ideally someone who is running a 700R can post about if/how they enable TC lockup

I have a TH350 and have 3:08 with a 2k stall behind my 411hp 355

I have Motive gears now. Made in Italy. IDK if US Gear is still made in USA. Several others now though are made in India

If you don't have posi, good to go with one if doing a gear swap as it does not increase labor
 

·
Registered
Al - Waterloo, Iowa
Joined
·
5,037 Posts
As Roger pointed out the torque converter to cam relationship is quite important. You can get a reasonable assessment of the cam by checking engine vacuum at idle and in gear while idling. Get those readings and then talk it over with your tranny rebuilder. They should have a recommendation at that point.
 

·
Registered
Joined
·
481 Posts
My 2 cents, lock up converter is a better cruiser, no slip and heat buildup.

Have you considered a 4L80E? More dollars and needs a controller but better gear ratios for a BB and far stronger in design.
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #8 ·
Hey Al, thanks for your response:
You can get a reasonable assessment of the cam by checking engine vacuum at idle and in gear while idling. Get those readings and then talk it over with your tranny rebuilder.
How do I check that??
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #9 ·
My 2 cents, lock up converter is a better cruiser, no slip and heat buildup.

Have you considered a 4L80E? More dollars and needs a controller but better gear ratios for a BB and far stronger in design.
I did.. but I don't have the other electronics (crank sensor, etc), and I came across a friend's 700 for free.
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #10 ·
My suggestion was to settle on rear gear first for what RPM you want at...75 mph as you note
Gotcha.. that's where I'm trying to vector in now.
you have a BB so not a high RPM motor so cruising at 1800-2200 RPM at Fwy speeds is a good range
Yeah, that's where I'm thinking I will set most of the time
If you have more than 14" of manifold vacuum your cam is not to big so a 2200-2400 stall would be good and you should be able to do without a external trans cooler although they never hurt with higher stall TC.
already have the trans cooler installed. I was worried about the 3500-stall TQ that came on the car generating too much heat.
I have a TH350 and have 3:08 with a 2k stall behind my 411hp 355
do you ever wish you had OD???
 

·
Registered
Al - Waterloo, Iowa
Joined
·
5,037 Posts
Hey Al, thanks for your response:

How do I check that??
You need a vacuum gage to start with. Check manifold vacuum. The easiest way is check it at a port on the carb that is below the throttle blades. Youtube will help you. Or post pics of all 4 sides of your carb and we can tell you which port to use.
 

·
Moderator
Joined
·
11,606 Posts
I like the 200r4 better than the 700s. They can be built stronger just like the 700s, plus then are the same length as the TH350 (no driveshaft mods). Getting a 200r4 from a Monte SS (I have that one) or a Grand National, they are already set up for 3.73s.

I have 3.55s and wish I put in the 3.73, my small block runs too low with those gears.
 

·
Registered
Joined
·
3,151 Posts
How do I check that??
A vacuum gauge you can sometimes borrow from auto part stores that have a loan-a-tool program, Ideally you should have one in your tool box. Harbor Freight has them for not much $

As Al noted you just put the hose from vacuum gauge on a manifold port on your carb to read vac at idle in park and then in drive. This will give you a solid indication on how big or small your cam is.

do you ever wish you had OD???
Sure. I only did the TH350 because I had one to replace the PG the car came with. If I did put a OD trans in it would be a 5 or 6 speed manual. I have a T56 car with 4:10's and really like that combo

Also the 200r should be considered if you are staying automatic. IMHO better geared. The 700r has a really low 1st but 2nd gear it is high. OK for cruising but not so much drag racing but since the 1/4 mi is not your thing it will work

The 4L80E can take a BB and is another option but the most $ to do that swap for automatic and I believe a tunnel mod to keep drive line angles right is needed

Plumb your current external rans cooler into the new trans swap,

If you have a 3500 stall now than you know what a high stall TC behaves like on the street. IMHO that is to much stall for a street car that will never see the 1/4 mi

For a shifter checkout Shiftworks for modding your stock console shifter for the OD trans
 

·
Moderator
Joined
·
15,638 Posts
I agree 100% but 200 are harder to find than 700. I’ve run 700 with 3.55 26” tires. Street car all worked well
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #16 ·
Plumb your current external rans cooler into the new trans swap,
Will most certainly do
If you have a 3500 stall now than you know what a high stall TC behaves like on the street. IMHO that is to much stall for a street car that will never see the 1/4 mi
agreed.. I hate the 3500 on the street
For a shifter checkout Shiftworks for modding your stock console shifter for the OD trans
I am running a Hammer Shifter from B&M
 

·
Registered
1968 Camaro SS Clone
Joined
·
692 Posts
Not to take a tangent, but have you considered a Gear Vendor’s overdrive unit. Bolts to the end of your TH350, shorten the drive shaft and drill for you go. Assuming you are happy with the TH350, it’s probabaly less work. You don’t get to lock up torque converter though so there is that.
 

·
Registered
Joined
·
394 Posts
I like the 200r4 better than the 700s. They can be built stronger just like the 700s, plus then are the same length as the TH350 (no driveshaft mods). Getting a 200r4 from a Monte SS (I have that one) or a Grand National, they are already set up for 3.73s.

I have 3.55s and wish I put in the 3.73, my small block runs too low with those gears.
Good advice,
often ignored.

Few mods kill a performance motor
than a high rear gear lugging motor.

700R4 provides way too low 1st gear producing uncontrollable launches, then, when it takes big jump to second, motor falls off its’ power band and rolls over. This mess is muted to some degree if one uses a computer motor.

Heavy, unreliable, expensive to build and junk gearing.
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #19 ·
Not to take a tangent, but have you considered a Gear Vendor’s overdrive unit. Bolts to the end of your TH350, shorten the drive shaft and drill for you go. Assuming you are happy with the TH350, it’s probabaly less work. You don’t get to lock up torque converter though so there is that.
I did consider it pretty heavily... This TH700 just fell into my lap. I am keeping the TH350 for a minute, so if I hate the gearing ratios of the 700, I will sell it or repurpose it and go back to the drawing board
 

·
Registered
Joined
·
55 Posts
Discussion Starter · #20 ·
Good advice,
often ignored.

Few mods kill a performance motor
than a high rear gear lugging motor.

700R4 provides way too low 1st gear producing uncontrollable launches, then, when it takes big jump to second, motor falls off its’ power band and rolls over. This mess is muted to some degree if one uses a computer motor.

Heavy, unreliable, expensive to build and junk gearing.
Muncie,

I get the launch issue, but I am not running this car on the strip.. it is street-only. Does that change your opinion any?
 
1 - 20 of 22 Posts
Top