[mcgruff1]

When converting a 4.3 to carburated in a originally tbi truck, do you need to get a new throttle cable bracket--the edelbrock one? I have a 1" spacer on if that matters.

In comp cam's catalog, for all the cam accessories it lists 2 part numbers: 1 is the "premium choice" and the other is standard, whats the difference between them for lifters? #850 is standard and #875 is premium.

What length valves do I need to step up to 1.6/2.02? Do I just order the same spec valve as stock but different head diameter?

Whats the stall speed of a stock 700r4 behind a 4.3?

 

[mcgruff1]

anybody?

 

[Ed W]

In reference to the throttle/ carb conversion:
There is no standard answer to your question.
You are expected to be the 'creative engineer' in situations like this.

 

[mcgruff1]

Well I know of some people here who have done this exact swap that might know. I think "89shortbox" and a couple others have.

 

[mcgruff1]

bump

 

[mcgruff1]

.

 

[89shortbox]

When converting a 4.3 to carburated in a originally tbi truck, do you need to get a new throttle cable bracket

nope, stock bracket works just fine.

for the valves, yes, order stock length with bigger heads.

Stall, I think it is between 1300-1500. It will very between
vehicles and how much torque they make.

 

[mcgruff1]

Thanks man

 

[lunatic515]

as far as the bracket for carb conversion goes, i have the edelbrock adjustable one and would never do without it. If you use the stock one, you can bend it, but it creates problems with your tv cable at wide open throttle, it can be done, but its so much easier with the ede bracket, well worth the money. As far as valves go, depends on how much lift you are going to have, I have +.100" in mine with .608" lift and works great. with anything below .500", stock length should be fine. the probem created with a valve thats too short for the lift used is that the rocker arm will try to roll too far towards the outside of the valve stem at full lift. it just screws up the geometry basically, and if that happens you will drop valves at high rpms. i would use stock length with lash caps if your still using the comp 270. the stall speed is hard to understand, they typically stall around 1500, but they are a tight converter, so the wont slip much at takeoff like a loose converter. you can never reach the true stall speed of a converter, just very close. I have a B&M converter for the 700r4 that has a 2400-2500 stall for cheap if your interested. the boltholes are wore a little and could be fixed easily with a helicoil kit, but will still work like it is. I would rather fix it than worry about it though. Ill take 95 bucks for it. it was only ran for about 4 months.

 

[lunatic515]

im not sure about the standard and premium lifters, if its a roller, shouldn't matter a whole lot, you could even get by with factory roller lifters if you have a hydrolic cam. im not saying its the greatest, but if money doesn't allow, you can get by.

 

[mcgruff1]

I decided to use the comp 266hr instead, got a deal on it. That ones got .500 lift too so Im probably going to get 2.02/1.6 stock length valves with it. Does it depend on what carb you use whether or not you need that edel bracket? Im using an edelbrock 600 instead of the holley I had. Thanks for the offer on the converter but Im way over budget as it is.

 

[89shortbox]

you can use the stock roller lifters up to .350 lift at the lobe.
(1.5 rocker= .525 at valve)

I used the stock bracket with a Holley carb (dont know about using with an edelbrock carb) and I had enough adjustment for the TV cable.

 

[lunatic515]

edelbrock carb should work fine with stock bracket as long as its not a mechanical secondary carb.