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Old 05-20-2011, 08:18 PM   #1 (permalink)
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1985 Caprice Computer Controls What?

I have an 85 Caprice with the stock lg4 (700r4) transmission and a 305 (H) engine. I'm restoring the car but the engine will be the last thing and I hope it will last several more years. I took off about 25 pounds of emission equipment over the weekend and was able to improve my mileage by almost 3 MPG. It has dual exhaust with no cat and an H-pipe. Still no check engine light and there is a bulb in there!

What does the computer control in this car? When I check out the Hypertech and Jet performance chip sites they indicate that the computer chip will affect the transmission as well as advancing the timing. I know the computer controls the timing because there is no mechanical or vacuum advance in or on the distributor.

I was thinking a stage 2 chip with a 180 degree stat and a K&N air cleaner combined with dual exhaust might buy me 20 HP. If I can get less torque converter slip or a higher shift point out of it then I can really justify the money on a 305.

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Old 05-22-2011, 11:42 AM   #2 (permalink)
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The computer controls the advance, but not the base timing. It doesn't do anything with the transmission, your shift points are controlled by the TV cable. As for the torque converter, the 700R4 has a lock-up coverter, you can't get any less slip than that.

1978 Caprice Classic Landau
350 2-bolt, stock 4bbl
Stock rebuilt TH350
Edelbrock performer cam + intake
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Old 05-23-2011, 08:20 PM   #3 (permalink)
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Thanks for the info. The best power mod will be a new small block that is completely free of computers. Do you happen to know what the electrical plugs going into carb control?

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Old 05-23-2011, 08:29 PM   #4 (permalink)
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^Your computer has a lean burn setting which the computer tries to keep the engine as lean as it can for a carburetor.

Best power return for the money would be to buy a Vortec 350 and custom build it up with a 4 barrel carburetor and HEI from a late 70's Chevy engine. When I get one and start the rebuild I am shooting for between 325 and 400 hp out of it, and mate that up to a custom built 700R4 to handle 400 hp.


1977 Chevrolet Impala Sedan, 305, TH200, 2.56:1, 110K miles, 37 Lifetime Warranty Parts.
1989 GMC C1500 Sierra ECSB 350, HM290, 3.08:1, 338K miles, 15 Lifetime Warranty Parts.

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