700r4 on a 250

[Gibbelstein]

So, I just got a '69 C10 with a 250 I6 and a 3 speed on the column. Also, I have a Camaro I have been amassing parts for for a couple of years, including (both from a late 80's suburban) a 700r4 and a 350 which I'll be building as a 383. Eventually I was thinking of dropping them both into the truck for the time being because the Camaro will still be a few years coming, and I like to tinker with stuff.

I thought about dropping the 700r4 in for the time being because I have it, and the overdrive couldn't hurt =) However, I have looked at everything I could on the site here to find out about the possibility of doing this, but I don't know if the 250 will have enough heft to work Ok especially at such low RPM's. I know that they used them in S10's, with 2.8 v6's but that is also a smaller truck and a faster spinning motor.

Has anyone done this? was it successful? and was it worth the time? I would like to do it just for the hell of it, but if it's been done and would be a waste of time, i'd like to know. Especially since I need to have any project buttoned up in time to go to work the next day.

Thanks in advance for any responses, and for all of the informative stuff I've been reading for the last couple of weeks.

[Tx Firefighter]

You should be good to go.

Believe me, that inlie 6 will have more torque than those limp wristed 305's Chevy put in front of 700R4's in the 80's.

[lilred67]

your gear ratio in that truck if stock should be 3.73's,with the od,should put you in the low 3.00's depending on tire size.that should put your highway rpm's around 2000, rite were that six cylinder makes its most power.my 250 turned 3000 rpm's @ 70mph with 3.73's and 33" tires.its out of its power band. with the low first gear ratio in the 700r4 it should take off really well.

[Gibbelstein]

Thanks guys, for the responses. That's kinda what I was thinking, I just didn't know if there was anybody that had done it before that could add something that I had not thought of.

Along the same lines, I was also wondering if I decide to drop the 383 and the 700R4 in If it would be best to do them at the same time, or if It would work out OK to do the tranny and then the motor. Am I wrong in assuming that any mods that I would have to do for the tranny (i.e. shorten driveshaft, etc.) would not affect the motor install and anything I would do for the motor swap (i.e. mounts, etc.) would not affect the tranny? Or am I missing something? I Haven't really looked into the motor swap at all yet...

Thanks again guys,
Chris

[mr402]

If you do install the 700R4 with the L6 write up a FAQ for it. My son has a 68 Cutlass with the 250 L6, with gas where it is we're thinking about putting a 700R4 or 200-4R behind it. Would be good to see if anyone else has done this and what problems they encountered.

[Scooter67]

I'm extremely pleased with the 700r4 and 4.3 v6 in my truck. 3.73 gears and really quick off the line.

[PICKMUP]

I put a 700 behind a stock 250 in a short stepside w/4:10 gears...hated it! No power in OD. It just died going up small hills.
I switched to 292 and that pulled OK...so, I added 4bbl & headers/duals/HEI and it was starting to be a pretty good driver.
Some day I should put that thing back together.

[Gibbelstein]

OK, so recent developments (some "***hole" torched my camaro in my driveway while I was sleeping) have changed things a bit. I am now thinking of doing a motor swap instead. I may take the 327 out of the camaro and drop it into the 69, since it will be a loooong time before I can fire up the camaro again. I just have a couple of questions for you guys.

1) Does anybody know the ratios of the 3-speeds, and the probable rear end ratio for the truck (69 C10 with no options whatsoever, w/ column shift if it matters)? I am gonna jack up the rear end and spin the wheel later to find out, but if someone can tell me the rear ratio I'd appreciate it.

2) I have been searching the board, and I think that if I do it, I'll drop it in with the I6 mounts, since moving everything else up 3" will be a PITA. Does anybody have a link to a I6 to V8 swap anywhere, so I can at least run through it before I tear stuff up?

3) Will the 3-speed be OK behind a V8, even with the *relatively* low torque of a 327? Or was the tranny made with the low RPM high torque of the I6 in mind?

4) Finally, Has anyone done this that can tell me if it was worth it, or if I'd be wasting my time/ working against myself? I enjoy working on these cars, but if it's a bad idea, I'll find something else car related to take up my weekend =) .


I realize that was long, so if you took the time to read it all, thanks. And if you have some information for me than thanks again.

Chris

"Just a little edit by Rod"

[Gibbelstein]

I just saw lilred67's post about the rear end ratio again. Thanks for that. I don't know how I could have missed it until now.

Chris

[krue]

I know of a few guys running 350's in front of the 3 speeds from the factory so the 327 ought to be alright, long as you ain't trying to hot rod it (them 3 speeds don't shift fast atall. )

[Gibbelstein]

Thanks, that's what I thought, but I'm by no means an expert.

While I'm thinking about it, what kind of tranny would it be? Is it a saginaw 3 speed? I am trying to look up the ratios, but I'm not getting too far without knowing what to call it =)

Thanks again,
Chris