355 cu in and 700r4

[gysgtc]

I have a new 355 eng with 700r4 tranny in my truck. The rear end is 3.08. When I flip the lock up switch the truck really bogs down. I have a stock edelbrock carb. Do you think the carb needs rejeting? Will it hurt to run without the lockup? Thanks

[Longhorn 70]

Running without lockup shouldn't hurt. It probably is only bogging because you aren't going fast enough when you flip the switch.

[luvbowties]

Originally Posted by gysgtc

I have a new 355 eng with 700r4 tranny in my truck. The rear end is 3.08. When I flip the lock up switch the truck really bogs down. I have a stock edelbrock carb. Do you think the carb needs rejeting? Will it hurt to run without the lockup? Thanks

Something to keep in mind: when you go into od, the engine goes from "seeing" the 3.08 to "seeing" a 2.16, which it probably did not like in the 1st place. [3.08 X 70% = 215.6 !] When u flip that lockup switch, it removes any slack the already-lugging engine was enjoying from the t-convertor. Sure we can all figure from there...
Sam

[bigmac73]

Need to change the gears in the rear end, go to a 3.73 or a 3.42

[hugger6933]

I agree are too tall for the 700 at just a regular hiway speed. If you will remember back and if you had one the 88-say 95C1500 truck[tbi][ because the 96 went to the vortec style head]were the same way they would "wander" for a lack of a better word in and out of OD around the 53ish mark and if there was a cruise control involved to keep it there and not your foot so that it stayed there it was really bad. A lot of that was solved by the General and the use of the 3:42 gearset. I think that may be another reason why you will find them more popular in the latter of than run than the early units most being the 3:08. The S trucks weren't immune from this either in fact they were more likely to happen to them because the truck was to heavy for the motors they had making that problem worse. I think you would solve your problem with a set of '42's but if a little more kick off the line would be more to your liking even though the 700's 1st gear is super low, the 3:73 rp would be the golden ticket. Jim

[gysgtc]

Thanks everyone. I have a 67 c10 rear end with 3.73 gears. Will they fit in a 72 rear end?
I think I will find someone to change my gears in the rear end. Love this board.

[slow-1]

I have the same set up as you.

350 (.40 over, mild cam) 700r4, 3.08 rear gears.

I have no problem at all with bogging...if I am driving up main street at 35 mph in od/converter locked and I get to the 55 zone I give it gas and it accelerates up to 55 with no problem. Of course if I really give it gas, it downshifts like it should and I get to 55 much sooner.

Out on the highway at 65 to 70 mph it seems perfect to me.

There are a LOT of people who say 3.08 gears with a 700r4 is no good...I drive mine every day and it works great for me.

[slow-1]

Oh yeah, as for not locking the converter.

With the converter unlocked, heat builds up fast...they say heat is the #1 killer of 700r4's, but I haven't burned one up yet so not sure.

[gysgtc]

I know i have to do some changes to my carb. Edelbrock 1406. As soon as I lock the converter the engine boggs down when I give it gas.

[slow-1]

Originally Posted by gysgtc

I know i have to do some changes to my carb. Edelbrock 1406. As soon as I lock the converter the engine boggs down when I give it gas.

At what speed (mph) is this happening?

You need to sort out your carb/motor issue first, then decide on gear swapping.

By the way, I have my converter wired to lock up when the trans shifts to OD, I have a switch for locking the converter when in 3rd for towing. This set up works good for me.

[Longhorn 70]

I drove my 700R4 unlocked for years. It has given me no problems since 1997. I did put a huge aftermarket tranny cooler in though.

Another thought on this is how is the cam dialed in? The engine may not like the lower RPM range. Is it a stock cam? If it is a performance cam, even mild one for higher HP, you may want to advance it 2º-4º for better low end torque.

[myyamr7]

Originally Posted by slow-1

By the way, I have my converter wired to lock up when the trans shifts to OD, I have a switch for locking the converter when in 3rd for towing. This set up works good for me.

I haven't done much research on it, but what you have sounds like what i'm looking for. Is there a lock-up kit to buy, and how did you figure to wire it so it would lock up in 3rd?
I have a 200 4R in mine and if I remember correctly, the guy that built it said the OD was even higher than a 700R4, I believe he said OD was .67 My truck also has the 3.08 gears

[slow-1]

Originally Posted by myyamr7

I haven't done much research on it, but what you have sounds like what i'm looking for. Is there a lock-up kit to buy, and how did you figure to wire it so it would lock up in 3rd?
I have a 200 4R in mine and if I remember correctly, the guy that built it said the OD was even higher than a 700R4, I believe he said OD was .67 My truck also has the 3.08 gears

I got mine with the trans when I ordered it from Bowtie Overdrives. They sell the kit on their website.

It is really straightforward.

One wire from the fuse box goes to a brake light switch then splits. One of the split goes directly to one of the terminals (there are 4) on the trans (this locks up the converter whenever it shifts to OD), the other goes through a switch I mounted at the bottom of the dash then goes to the terminal on the trans right beside the first one (this locks the converter when the switch is turned on in other gears).

It's been 11 years since I did it so I don't remember which terminal goes with which wire...but I can look next time I am under there.

[slow-1]

Originally Posted by Longhorn 70

I drove my 700R4 unlocked for years. It has given me no problems since 1997. I did put a huge aftermarket tranny cooler in though.

The only time I have had an issue with it heating up was one time towing my boat (4000#) i was in 3rd and did not lock the converter...things got hot real fast, but cooled right off when I flipped the switch.

[Jimjific]

Slow-1,

Any chance you know what mpg you are getting with that combo? I have the same set but in a 69 step and was thinking of going to an overdrive.

Thanks,
Jim

[gysgtc]

Just removed the metering rods and found there is no spring for the driver side rod. Also the 2 rods are different sizes. This was suppose to be a new carb.

[slow-1]

I have not checked it since my last engine rebuild but was getting 17 to 18 the last time I checked...which was probably right after I put in the trans 11 years ago.

I drive it a fair amount and seem to need gas at the same intervals as my wife who drives a Honda Pilot (20 gal tank and 17-20 mpg).

[slow-1]

Originally Posted by gysgtc

Just removed the metering rods and found there is no spring for the driver side rod. Also the 2 rods are different sizes. This was suppose to be a new carb.

Dang...did you buy it new?

[gysgtc]

I bought the whole engine in pieces from a guy. Every thing was new or rebuilt and I had to put it together. I would have never thought that a spring was causing all these problems. Are both metering rods suppose to be the same size? Thanks for all the help.

[slow-1]

I have no experience with Edelbrock carbs.

I would start a new thread about it to see if you can get someone who knows them to help you.

[Lattimer]

Originally Posted by gysgtc

I bought the whole engine in pieces from a guy. Every thing was new or rebuilt and I had to put it together. I would have never thought that a spring was causing all these problems. Are both metering rods suppose to be the same size? Thanks for all the help.

Yes, both should be the same.

[Coley]

What tire size are you running?
...noting that the bigger the tire the worse this situation becomes.

Coley

[gysgtc]

I am running stock tires. I think the whole problem is the metering rods and springs. Ordered the set today so now can't wait for them to get here.

[gysgtc]

Thanks Shawn.

[gysgtc]

Just got the metering kit and put in the rods and springs and it runs like it should. Now I'm going to play with different rods and springs.