got a heck of a deal on a georgia 1990 rs t-tops, only surface rust...but its got a 305/700r4.....had a 70 split bumper with 307 points and muncie long time ago. dont know anything about 305/700r4 and would like to take the 90 rs olds shcool....... lose the computer and go with a 350 or 327 can i use the 700r4 or do i need to find a 350 turbo.........and about any new wireing that might be needed?..... anybody help with whats involved. thanks

 

any question you can think of with respect to that 21 year old car has probably been asked/answered several times. Use the search function and you'll find a wealth of information; good luck.

I was beating my head against the wall with my steering column, a quick search and there was my answer.

 

Welcome to TGO!

There's a ton of posts about swapping almost anything into these cars.

Sounds like you want to do basically what I did with my 1992. You can keep the 700R4 (gets better mileage anyway), remove the 305 and install 350 with no problems since all SBC are the same. There are 2 major wiring harnesses, driver side remains, pass side goes. There's a few wires that run between the two, just fish out the wires that originate from the pass side harness. I recommend not cutting out any wiring, just tuck it in the pass side fenderwell sight unseen just in case you need later. All gauges will function normally.

You can use the intank electric fuel pump as well - just need a Mallory 4309 fuel pressure regulator to reduce fuel pressure for a carb (I'm assuming you want a carb).

Only other thing is torque converter lockup - can rig your own (see sticky in carb section about TCC Lockup), or buy a kit to install in tranny to lock it (normally the computer locks it, but you won't have computer any longer).

700R4 tranny is very particular about the TV cable - these are NOT just kickdown cables like the old days - the distance the cable is pulled and the pressure used to pull it is critical - wrong and it can burn up the tranny. You need a good strong throttle cable bracket and a TV geometry corrector for the particular carb you choose to keep everything straight.

Pass on the 327 - was the thing in the old days, but doesn't hold a candle to a 350.

Check with local emissions laws, can't legally carb these cars in many states/locations - would be a shame to do all the work and not be able to get plates!

 

Welcome aboard thirdgen.org.

Reality check - That 305 TBI has more power than the old 307 2-bbl. Runs cleaner, drives better, lasts longer, goes farther on a gallon of fuel, etc.

If you insist on downgrading, there is a Tech Article linked from the thirdgen.org home page that goes through the details of what it takes to go from EFI to carb (also in the stickies in the Carburetor forum).

Now, if you actually want to improve on the 3rd gen system, look into an LS1 swap. Computers are a hot rodder's best friend.

 

thanks for the info