Horrible acceleration- timing, shift points, torque converter??

[Black70c10]

Hey guys,

I'm new to the forum. I recently took my 70 c10 to Dukes Speedmaster to to get the torque converter lock-up switch installed. They did great work and I was very pleased with them. But they couldn't really help me with my acceleration issue.

I am looking for a shop somewhere in Houston that can tune carbuerated engines and that may also have a dyno. I've got a very clean 350 with headers and a mild cam, but it runs unbeleivably slow. It has a rebuilt 700R4 trans with a 1800 RPM stall. However, it just doesn't have any get up and go because it's not running throughout the power band. For instance, say I'm cruising at 20 MPH and mash the throttle to the floor... it only drops down into 2nd gear and then it shifts to third waaaay sooner than it should.

I was told that my kickdown cable is set up correct, fully taught with WOT, so I'm wondering if this may be a timing issue of some kind? Or maybe the shift points need to be adjusted? The timing appears to be set ok, it idles great and it drives very well until it comes time to get on it. I've driven crummy old beat up 350's that had twice the acceleration that this thing has. With an electronic ignition, cam, headers, et.. this thing should be halfway quick..

Any recommendations would be greatly appreciated!

[geezer#99]

Timing set OK!!
What's the initial timing set at?
What carb?
What intake?
What's the cam specs?

[Lee H]

Welcome to the forum! Lot's of very knowledgeable folks here more than willing to help out. In addition to Gezzer's request, tell us able your distributor, have you verified the mechanical and vac advance are working?

[Longhorn 70]

Timing shouldn't affect 700R4 shift points. What happens when you pull it down to 2nd manually?

You may also want to read 700R4 TV cable adjustment procedure.

[Black70c10]

Appreciate all the responses. Unfortunately, the previous owner could not give me any of the cam specs. It has a Weiand 1546 intake manifold, a 650 cfm edelbrock carb (1806 series) and a pro-billet MSD distributor w/out vac advance. I just figured the timing was set ok because it runs and idles well. I checked it a while ago and it looks like it idles at 35 degrees... This seems a little high. Shouldn't the base timing be somewhere in the 12-15 degrees range?

Appreciate any help.
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[Black70c10]

One other thing, I didn't have time to check and confirm that top dead center is in fact set correct, or that the marker falls on zero at TDC. I'll have to do this when I get back in town. But for now, assuming that it is marked correctly, any advice would be appreciated!
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[geezer#99]

I was just thinking that. Confirm tdc and your timing marks. You might have a mismatched tab and balancer or a slipped balancer.
With your combo you might need up to 18* initial.
Also check to see if your carb is opening fully. With or without the tv cable hooked up.

[NVBUYER]

Hello! You should definitely check you TV cable adjustment. While it may be taught the outer sleeve controls some line pressure from my understanding. Hopefully clinebarger can chime in and offer more on this.

[trac209]

Your tv cable setting controls shift point and line pressure in the trans. Do not drive with a mis adjusted shift cable on a 700r4 or that tranny will not last very long. Look up cable adjustment procedure or take to somebody that knows what they are doing so it doesn't burn your trans up.
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[cdowns]

what rear end ratio?? tire size??
exactly what type of vehicle are you comparing this truck to ?? acceleration for a beat up old ragged out nova or comaro will b quite different than a 21/2 ton brick like these trucks are

[Black70c10]

@geezer- adjusted the timing down to around 20 degrees from 35 and it seems to run a little crisper. Ill continue to tweak the timing and carb to see wnat works best. Confirmed TDC too by the way. I think it still has something to do with the shift points, it's not staying in gear long enough before it shifts. It's really just a cruiser though, so I'm happy with it for now. Thanks for the help.

[Black70c10]

@trac and longhorn- thanks I appreciate the advice, will look into it

[BrianG]

I'll second what cdowns asked. What gears and tire size? If your running 3.08's and large tires, your not going to have great low end acceleration and take off. If your comparing a setup like I just explained to a new Silverado, then it would surely seem very doggy.