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Old 05-31-2009, 02:03 AM   #175
rfmaster
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Join Date: Oct 2003
Location: OC CA
Posts: 1,374
Re: Tbi swap build thread

Hey BrontoTX

Welcome to the board. IMHO, Mutts make best friends for life.

My '75 is as simple as it gets - no cruise control. I am not in a position to make comments regarding cruise controls.

VSS input - this is a tricky one, but you can probably adapt later DRAC unit to drive both ECM VSS input (2000ppm) and cruise control computer. The critical part is re-programming DRAC to match your rear end gear ratio, tire size and spedo gear ratios. In the past I found a page were this was documented, but it escapes my recollection at this time. Try Googling. Otherwise, get JTR 2000ppm VCC unit and DRAC in series with each other.

I am not a column expert - try a focused post instead.

TBI comments.
1) Definite yes, I pick-up B-Body FSM - it was cheap and covered ECM that I was using for my conversion.

2) I used pre -87 specific TBI intake, Holley 300-49. (I did not care for grinding) Alternative is to get Q-jet to TBI adapter plate and keep original manifold.

3) There are about dozen variation in 700R4 internal wiring. Two years later I have not hooked up my TCC function in my 700R4. Yes, I know I am bad.

3a) - Avoided back pressure problem by using 3/8" line everywhere. I also use Carter P5000 inline pump - works great. In addition I use a surge tank and a lift pump - both of my tanks are fully selectable and functional.

4) I run EBL conversion with my ECM - the best thing for tuning. I still have some tune work to do ( I have false knock due resonating exhaust system). Overall gas millage went from HWY 13MPG to about 17MPG (700R4). Original HWY (TH-350) was a dismal 10-11 MPG (I have 4.11 gears and 14 bolt rear)

//RF
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"The Beast"

1975 Chevrolet C20 longbed
350/700R4! with 3inch body lift
Dual Flowmasters Super 40's!
TBI retrofit completed (2007-07-29)
New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)
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