Turbo 400 to 700 r4 conversion on 72

[photovette]

The only thing I haven't replaced on my 'vette is the left back-up bulb and the transmission--and the bulb just burnt out. So, I've been researching what I would do when the my transmission does decide to go **** up--now, I'm fairly convinced I'd just put in a 350C--a lot less trouble, expense, and mods, but a respectable MPG gain and RPM reduction at highway speeds.

For the price of an 700 or 200 OD transmission (+install and mods) , I could add about a grand and put in a six-speed manual--which is darn tempting too.

 

[dfw81shark]

dfw81shark: What i really wanted to say also, is there should be 3 shifts, (or four speeds) if the lockup us working. I've found, (and continue to find), reasons for the lockup not to work. The 80 in California, and 81 all had th350C (for computer) auto trans. (unless of course you had the 4speed) The lockup depended on temperature, computer, and just yesterday found out a speed sensor on the back of the speedometer(?) If you are not getting lock-up, it would be worth it to correct this to improve gas milage and less strain on the engine. I'm probably going to switch to one of the overdrive trannys: the 200R4 or the 700R4. If I wasn't , I would probably bypass all of the above problems with a B&M harness that costs about $160 at Jegs.

In that case, my lockup is DEFINITELY NOT working. It hasn't since I got the car, and I have had the tranny rebuilt (still not working, didn't have the knowledge that it wasn't working this time last year). All signs are pointing to overdrive, even though I'd rather not spend that right now... Also, I noticed sitting in the drive-thru at Wendy's tonight that she likes to start pouring smoke out the sidepipes when idling for a couple of minutes. Sounds like rings, which sounds like I'll be pulling the motor- I'll be up there with photovette on replaced items. I've already got a 10:1 355ci that needs to be gone through- sounds like my candidate.

 

[dfw81shark]

As for settings, I installed the carb, warmed the car up, set the idle mixture, idle speed, a/c idle increase soleniod (whatever it's called), and secondary opening. Followed by choke and fast idle the next morning. It's very easy. This is something that everyone should be doing to their carbs every tune-up anyway--we've got spoiled with our modern fuel injected other cars, and forgot what a real tune-up involves.

This carb (1903) is indentical with the original--everything mounted and hooked up the same. Except for an extra bowl vent which I put a rubber cap on.

I looked into their other carb, and by the time you add all the stuff you need to get it to work on a stock 'vette (10 separate and distinct and individually priced parts), it was about the same cost as the new Quadrajet. I bought mine at Pace for about $435.00. Besides, the Edelbrock tech said that the Quadrajet was a far superior carb--I took their advice.

So if I had a nonemission vehicle, how many of those 10 items would I need? I am assuming you are running a legal car. The reason I ask is that I'm thinking of getting a 2nd carb for my camaro too, and $475 (Summit) * 2 is a bunch. If I could get by with a cheaper, say Road Demon Jr., which claims to get good mileage too, I could get 2 of those for just a bit more than the price of 1 quadrajet. Again, that's before the extra items I may need to buy. I've seen bad reviews on the other Edelbrock carbs, and I want to stay away from Holleys. Both my cars have very similar setups, with no emissions junk. Convince me I need to bite the bullet and get 2 quadrajets anyway.

As indicated in the last message, I will be pulling out the L81 and putting in the pull out of my truck after I go through it. The new motor has an aftermarket intake, so there'll really be nothing "vette" about my vette engine when I get done. Don't worry, I'm keeping the L81 intact whether it is worth more if I get rid of the car or not. I could just re-ring it, but after all the hassle, I'd rather pull it out and get a bit more performance with the new engine. Hopefully my carb swaps for better mileage won't be cancelled by the engine swap. The carb on the truck motor now is junk, so it'll be most likely thrown away (some Edelbrock).

And I couldn't find the Edelbrock 1903 or any other carbeurators at Pace.

 

[photovette]

Yes, I keep mine completely stock--emissions and all--though 48-state '77's didn't come with an air pump/AIR system otherwise I might have yanked that system--I did on my '81 in 1983.

Let's see if I remember:

You need the EGR spacer/adapter
The 90d Bango fitting
Fuel line & filter
The cruise control adapter
The wire etc. to hook up the electric choke ('77 has hot air choke)
Oil pressure switch for the electric choke
Idle compensator kit
Linkage kit for kick down
Plate & gasket to cover the hot air choke hole in the intake manifold

And I'm forgetting something...

But for the 1903 Quadrajet, I needed nothing. The cruise control post and idle compensator soleniod from my old Quadrajet swapped over and installed perfectly (as factory) on the new carb. It was a 15 minute as factory install.

WOW! I just checked the prices on the Edelbrock Quadrajet at Pace, $598.95! I paid $435 about a year ago there--that's what the reconditioned Edelbrock Quadrajets cost now almost--what a hike!

http://www.paceparts.com/index.asp?PageAction=PRODSEARCH&txtSearch=quadrajet

 

[like2drive]

wonder what the difference is between the 1904 and 1903? I've seen both recommended. Like dfw81shark, I have an 1981 original which means the computer mess.

 

[dfw81shark]

wonder what the difference is between the 1904 and 1903? I've seen both recommended. Like dfw81shark, I have an 1981 original which means the computer mess.

Correct me if I'm wrong, but the 1903 is a Hot Choke, and the 1904 is the Electric Choke. I think the 81 is an electric, but I haven't checked. I think the way to find out is to a green wire attached to the choke on the passenger side of the carb. If you have that, then you have an electric choke...