Re: Gear Vendors Overdrive Unit

[fasterthanu]

Re: Gear Vendors Overdrive Unit

Are any of you out there running this with a 700R4 trans? Big performance difference? I am running my 76 vette with Dual quads, full race cam, Pro Action Heads open chambered, 700R4 with 2500 stall speed, 4.11 rear end, and hooker super competition headers/sidepipes with JCL spiral Inserts. Unfortunately all of these mods are done to the original block, with 8.5:1 compression and 100,000 miles on it =P . When I raced my buddies super charged mustang, 92 I think, he pulled like 1/4 car ahead of me in first, and he opened it up to about 3 car lengths total at the end of about a 1/4 mile. Now he does have a 5 speed stick shift, and a charger, so that is a big difference. But I believe the drop between the 3.08 1st gear and second gear is probably what is doing me in. So, I was thinking about going to gear vendors Overdrive Unit, or possibly, the much loved 6 speed conversion =)

 

[page62]

Ummm....I'm sorry to be blunt, but...

Why are you throwing money at the driveline when the engine needs serious attention? You're bolting a bunch of stuff to a tired, old L48. Quite frankly, you need to pull the engine and do a serious rebuild, or drop in a ZZ4 or 350HO. For the cost of the GV OD, you could have a badazz engine!

 

[1979toy]

I'd be real interested to hear about it if you can get a Gear Vendors O/D unit to fit in the driveshaft tunnel of a C3.
I think that a lot of your traction problem comes from your 4:11 rear gears being mated to the lower gearing in the T700. Try swaping in a set of 3:36 to 3:08 gears for a session at the track and see if your times don't pick up.
If your heads are 64c.c. steel heads then you've got almost as much compression as you're going to want for running pump gas if you've got a short duration camshaft like the stock cam. As long as your compression check OK then I wouldn't worry about the short block being a problem.
My 100,000 mile short block is doing fine with the mods I've done to the top end of my engine.

 

[fasterthanu]

Actually, the whole top half of my engine was rebuilt. I am not burning any oil, and if I need a rebuild, it will be cheap enough being that everything on the top half is new, so it can be reused. As for gears... With my cam kicking in at 3500 RPM, a 3.08 or 3.36 isn't going to give me the get up and go, i won't be in my power band too much. I did have a 3.08 in here even after the 700R4 upgrade. It pulled decent, it was a big difference, but now with the 4.11 the difference is night and day. Oh, and with a 3.08 I was running low 15's.

 

[fasterthanu]

As for the ZZ4 or the 350HO, throw them in, and you will with any luck hit high 13's low 14's. With the difference split between 1st and 2nd gear, that would make a big difference. I probably will do my engine first, but either way, it will make a big difference, and I would like to hear from people that have it, and can either say yes, it made a BIG difference, or no, it didn't.

 

[MaineShark]

I'd be real interested to hear about it if you can get a Gear Vendors O/D unit to fit in the driveshaft tunnel of a C3.

I was curious, so I emailed GearVendors. They said it can be done, but requires a small area to be modified to clear.

Joe

 

[fasterthanu]

wow, I think it's real cool they got back to you so fast. I seem to be asking a lot of stuff people haven't done too much lately. First asking if anyone out there had a 2-speed rear end installed in their vette, now this. Must be that kinda day... Hmmm.. 2-speed rear end, strong engine, and a gear vendor od system....

 

[MaineShark]

I emailed them a few months back

But they did get back fairly quick, as I remember.

Joe

 

[AKRAY4PLAY]

you stated that you are running a "full race cam" that comes in at 3500rpm and have a 2500rpm stall converter, i would start there. you are most likely over cammed for your engine configuration and stall converter. the dual quads and cam are for high rpm running and the heads and tranny are more suited for low end torque. the combination may be fighting itself for best performance. what are the specs on the heads and cam?? what does your comp test read for all cylinders?? and most important, were are your shifts at rpm wise????? dual quads and big cams kill lowend power, and unfortunately you have both. your set up will work if you are shifting at 7500 rpm, but your heads and the lower end are taxed heavily. give us some more specifics on exactly what you have, and maybe we can help you more. Brian

Joe, how's the motor coming along?? just a little curious.

 

[AKRAY4PLAY]

oh ya,
for the gear vendors overdrive, all you have to do is dent the tranny tunnel with a hammer in one small area and cut the driveshaft down. if memory serves correct, the driveshaft needs to be cut 8.75 inches. the wiring is supposed to be next to idiot proof. Brian

 

[fc3]

Brian, My cam and tq converter both come to life at 2500-2800 RPM. The dynomax mufflers come to life as well... The big problem... not enough road/ cant keep my foot out of it!!! When it shifts into second it is a scream-tires/ 4 barrel/mufflers itsa blast. Fred.

 

[AKRAY4PLAY]

Fred,
i am glad to hear that things are still going well with the ride!!!! the power is an addictive thing isn't it?? i had a nifty cruise today, several guys broke out their Vettes and were rolling around town. there were 4 C3's, 5 C4's and 2 brand spanking new C5's. we all seemed to gather in at the mall by accident. i was the last to arrive and leave. everyone hung out for an hour and bs'd. it was funny to learn that 4 of the guys had seem my video and not a single one wanted to run at the lights. i almost had the C5's talked into a run until one the C4's brothers spoke up and enlightened them to what was under the hood. i guess i will have to settle for the track to really prove the car. Texas is the second largest state, so i know there is some open road to let her roam wide open. glad to hear your still happy with the motor! Brian

 

[fc3]

Brian, the C5's dont want any part of your C3...Texas may be second largest state but we got a lot more people here in E. Texas. Been hard to find a spot to really open her up. The 3.08 dont even hit the power band till after 70 mph (2700 @ 70mph). But she will fly from 70 to ?(a high rate of speed). I cant believe how fast the roller will build RPM's. I still havent done a major burnout... still kinda scary. Fred.

 

[AKRAY4PLAY]

Fred,
i know what you mean by scary. my car still makes my butt pucker. keep getting used to her, in short time you will get comfortable and lay out a nasty smokey that will shame mine. and yes, Texas has way more people than Alaska, and all the good looking women! have you thought about a rode trip down the coast?? i would kill to have my car where you are. i still remember being a kid and coast cruzing to Kingsville and going to the King's Inn to eat, the best frog legs i have ever had!! Brian

 

[MaineShark]

Brian: still working on the plan. I was shooting for August as an installation date, but I think I need to replace the radiator, and possibly the transmission, so that might delay things, financially. I want to do some sort of performance modification before the Shark turns 25 in August, but a better transmission would qualify. Then I could always do the motor over the winter.

I just got my current setup on the dyno (since it is not original, I was curious what it was making). Two-hundred horsies and a hair over 250 ft-lbs, at the rear wheels. So it is close to stock... definitely needs an upgrade

Joe