carburetor

[walt]

Can anyone help me with a suggestion for a substitute carburetor. I know the original stock carb on my 79 scout is a Carter TQ. My mechanic seems to think that 650 cfm is sufficient. I think Iread somewhere that the TQ is around 750cfm. My engine is a 345

[78ssii]

650cfm is just fine. there is no need for something higher. I am running a Holley 350cfm and it works just fine no matter what I am doing.

[Allan E.]

Agreed. 650 works because most of the time you are just driving on the primaries.

The 345 originally did great with a 325 cfm carb. It can't really use more than that. The 4 barrel was put on there in the late 70s purely for emissions control. Naturally, you will have a higher cfm with the 4 barrel because that's the wide open throttle rating. The t-quad was originally chosen because it only uses as much as it needs.

As to "which" carb you can use, I believe there is a 390 cfm Holley now available that works great. I have been using square bore manifolds and off-the-shelf Edelbrock 1405 carbs for 345 and 392 engines. They require very little tuning, and once they are dialed in, they work great. Some folks go to the truck avenger series for the off-angle operation, but I have not found the need.

[walt]

I really appreciate your help. Its great to have such a good resource available.
I'm really glad I found this forum!:)

[chip trapp]

walt, although i have never tried replacing a thermoquad on an international engine, i have on several ocasions replaced a thermoquad carb on both small and big block chrysler engines with a rochester quadrajet and found this to be a very effective swap, it bolts right on and is easy to adapt. if you are planning on buying a new carb, i would go with the holley or edelbrock, but if a good used quadrajet is available, you may want to give it a try, best of luck with your project....chip

[walt]

Thanks again for all the info. I'm a new scout owner and really appreciate the knowledge. I picked up a Holley 410 w/ 390cfm on ebay last night. It should arrive by the end of the week!:)

[sturner]

Thanks for all the in put on this site about carbs. I have a 345 and we can't get it to have a smooth idle. My friend suggested my carb. may be too big, as we put a kit in the carb and cut the fuel down as much as it would let us, and it still seems to be loading up on gas. Sorry I left info. on what size the carb is in my shop, but is it possible that a too big of a carb would cause it not to idle well, it seems to run great when we reb it up? Thanks Sid

[sturner]

[QUOTE=sturner;512]Thanks for all the in put on this site about carbs. I have a 345 and we can't get it to have a smooth idle. My friend suggested my carb. may be too big, as we put a kit in the carb and cut the fuel down as much as it would let us, and it still seems to be loading up on gas. Sorry I left info. on what size the carb is in my shop, but is it possible that a too big of a carb would cause it not to idle well, it seems to run great when we reb it up? Thanks Sid

[scoutguy66]

[QUOTE=sturner;512]Thanks for all the in put on this site about carbs. I have a 345 and we can't get it to have a smooth idle. My friend suggested my carb. may be too big, as we put a kit in the carb and cut the fuel down as much as it would let us, and it still seems to be loading up on gas. Sorry I left info. on what size the carb is in my shop, but is it possible that a too big of a carb would cause it not to idle well, it seems to run great when we reb it up? Thanks Sid

I wouldn't think the big carb is your problem, I have seen 1000cfm's run on 350 chevy's that idle fine. You should be able to cut the fuel down to nothing with the air fuel mix screw. Find that screw, turn it all the way in, then out 2-1/2 turns and start there. turn it down till the engine runs rough, then out a bit and it's adjusted. This issue might be caused by your timing and point adjustment(if you have points) also, so check those.