Ok, I have a 86 Camaro. I put a 350 in it. Bored .060 steel crank, flat top pistons,comp cam 470/470 lift 270/270 duration-224 @.050, aluminum heads 2.02 int and 1.60 exh edelbrock 600 cfm carb. Hei dist. My issue is it doesn't launch good. After it gets to about 3000 rpm, she takes off. The tranny is a th350. I bought it cuz it was built strong and has a 2500 stall. At idle, the timing is a hair past 12 degrees. I replaced the rear end with a 373 posi. I was hoping for a quicker launch. I realize there are a lot of variables here, but does anyone have any ideas on where I need to go from here? Thanks Larry

 

Everything seems good except the TH350. Get a 700R-4.

 

When I got the car, the computer was gone along with the harnesses. No motor or tranny. I had to build her from scratch. Doesn't the 700r4 run with the computer?

 

Only the TC lockup. Everything else is still mechanical - springs & weights for shifts, and a TV cable.

Hopefully you don't take this offensively, but are you actually loading the torque converter up to 2500rpm when launching? You wording makes it seem like it has quite the distance to travel before it gets to 3000rpm. Just thought I'd ask - sometimes the simplest solutions are the best.

 

I take absolutely no offense. Any help is appreciated. I have questions about the 2500 stall. I've been asked that pre load question before. Perhaps I need to study up on the stall converter before I assume it has one. I bought the transmission and converter under the idea it is a 2500 stall. I don't know it for sure. Is there an easy way to check? Back to the power, when I get on the gas, it kinda goes. A few seconds later, you can feel and hear the engine come to life. Roughly 3000 rpm. If I try to hold the brake to 2500 rpm, the tires just smoke.

 

Do you get a bog or hesitation if you try to go to full throttle at idle, in gear? If so, it's a carburetor problem. If not, watch the tach next time you leave a red light. Light turns green, move right foot from brake to gas, instantly slam go-pedal to floor while watching tack. The tach needle will jump, then you'll feel the car begin to move, or the tires will break loose. Whatever rpm you saw is your "flash stall".
Try it again with the brakes AND E-brake applied to the maximum. Whatever the rpm is when the tires start ti turn is your "footbrake stall".
Go get those readings for us, then report back. even so, your effective first gear is no better than if you had a 3.08:1 axle with a 700R-4.

 

Ok. I do get a very slight hesitation when a romp on the gas. I have the accelerator pump at the longest travel. This is where its at its best.

The flash stall is 1400 rpm, and the foot brake stall is 1200.
Thanks Larry

 

I am going to look into a 700r4. My th350 is the 6" tail shaft, so its probably going to be costly to convert it back, but I can get some figures.

 

It's not a 2500 stall. It's a stock 305 converter. For the 700R-4, you can find cheap re-manufactured Corvette converters for around $100 that are supposed to be 2200 stall, but if you want to go that route, the converters for the 4.3L V6s are slightly better results. If you want to be sure of twin black stripes on demand, then the B&M 70418 will do it cheaper than any other, and will be strong enough for your combo.
Also, with the 700R-4, your cruising rpm will drop to 2200 at 65 mph. You'll love that, too.

 

take the auto out and go t5 or t56 ... then theres no torque converter variable .. only your pedal skills :P thats what i did on mine , even though im running a crappy 305 with 210560 miles on it i noticed a better launch and it seemed to have more power.

 

The truth is, you were getting more of your power to the driveshaft. About 9% more.

 

I don't see how a 700R4 is going to really help your situation here... Yeah it has a steeper first gear but I guarantee your problem is tuning and torque convertor related... Fork out the $250-350 for a new one that is right for your combo.

You say your timing is at 12* at idle... how fast does it advance and what is the total timing? Also, for lack of a better word, your "600 edelbrock" probably sucks... I'd say a 750cfm 4160 style Holley would be a much better choice and you can find them all over the place used for cheap.

Do you know what your compression is at? and what brand "aluminum heads" do you have?

 

3.73x2.52 is not enough gear for a good launch. I've tried it more than once.
The 600 is too small for top-end breathing, but for getting across an intersection with that lame gearing, it's plenty.

 

with those gears and a good stall converter their is no reason you shouldnt be roasting tires when you romp on it from a standstill its more of a tuning issue than a trans issue aside from the low stall torque converter.

 

I have a TH350 with a convertor that is about 2000RPM too tight for my motor along with 3.92's and a 27" tall tire... The car will do 1.60 60ft's on motor and yank the driver's side tire a few inches off the ground. I'd say that's a pretty good launch.

The steep gear of a 700R4 is fun until you actually start making power and then it becomes annoying for 3 reasons: traction, duration, and the fact that you need to fork out a lot of dough to build one that'll actually live the abuse. When I had a 700R4 the car would not launch very well at all because the first gear would be so violent that it'd spin the tires. When it didn't spin, first gear was so short that you would have to shift before passing the tree at the track. Finally, my stock 700R4 died within a summer of abuse and then the "built" one I put in didn't last much longer.

...After killing both 700R4's my friend gave me a TH350 that had been sitting in his yard for years. We took it to the shop, threw all it's guts inside a parts washer and then rebuilt it using a cheap non-performance parts store rebuild kit. Total investment was $200 for the trans and $350 for the convertor and it has been alive for almost 7 years now behind 550+HP with thousands of miles of street abuse and hundreds of 1/4 mile passes.

 

Thanks 88IROC. I plan on putting in a 2500 stall converter. I am using pro comp heads. 2.02/1.60w/64cc combustion chamber. I don't know how to test how fast it advances or what the total timing is. I had a friend look at it during the build. He said my compression is 10:2-1. I don't know how he discovered this. As far as carb. Ive been told go holly, but right now, I'm stuck with edelbrock. I bought a 750 cfm but it ran to rich. The engine is running really pretty well. After I was notified the converter is stock(thank you Atilla) I'm thinking that is my issue. We will see. Is Hughes a good brand?

 

Hughes is a decent brand for the streetuse and some light duty track use. But do not use nitrous or any other power adder behind them.