TireSmoke.org

MostMint wrote:Most of the time this problem comes from not enough fuel dumped in to overcome the "stall" in the air when you open the butterfly in the carb. The way to fix this is install a more aggressive accelerator pump cam and/or a larger shooter nozzle to et more fuel in faster to compensate.

I know nothing about the Edelbrock but on a Holley these are easy changes. I assume also that your accelerator pump cams are adjusted properly. You'll need the chart that shows which cam is the best (they are color coded) and you'll need to know your current shooter size. I bought a box of parts from Holley that has the cams and the shooters a ways back. I looked in it tonight and it appears I gave you several shooter sizes a while back (I left a note for myself). Maybe you still have them and can remember where they are?

It's funny you say that, because I do have a selection of about 3-4 shooters in my parts box along with an assortment of pump cams. I found that box in the basement that had a lot of my various carb parts. I didn't remember ever buying them (I might've bought the pump cams, I seem to have a pretty complete set).

I have a bigger issue than an acceleration pump. The drivability is just not very good in general, even when making slower throttle movements, which makes me think the basic jetting is off. Being that both these carbs are 'used', I might even try what has worked well for me in small engines -- just run some fuel system cleaner through it. I've had that fix a bunch of poor-running lawnmower size engines.

-Dave

You might also look up the stock jetting for the carbs and go back to that.
Even if you have to tear those carbs down to no moving parts, buy a kit and rebuild you'll still spend a lot less time than the EFI setup.

You could always pop the 600 on there from the Vette for a short hop to make sure the problems are all related to carb and not ignition or ?

BTW, I have your jet kit in my cabinet...

-BP

Basement Paul wrote:BTW, I have your jet kit in my cabinet...

-BP

Really? The #82 - #99 jets?? I couldn't remember who I loaned them to!

-Dave

MostMint wrote:You might also look up the stock jetting for the carbs and go back to that.
Even if you have to tear those carbs down to no moving parts, buy a kit and rebuild you'll still spend a lot less time than the EFI setup.

Actually, that is what I did from the start, which is why I was surprised when neither worked very well, especially compared to the Eddy 600 on the Vette. I even threw on my old 3310 and it doesn't run right either. In fact, the engine wont stay running for more than a few seconds with that one. But I have literally 10-15 minutes of effort into that one. So I'm kinda feeling 0-for-3 on my carbs right now.

I have a fair degree of confidence in the ignition. This distributor is a brand new large-cap HEI. I'm seeing what I'm expecting to see with the timing light and my balancer, and it sounds/feels right.

To be honest, with the mechanical pump working again, I feel like I could make up a quick surge tank and have the EFI working right in short order. I'm looking forward to putting it back on at some point. The grass is always greener on the other side, right?

MostMint wrote: You could always pop the 600 on there from the Vette for a short hop to make sure the problems are all related to carb and not ignition or ?

I realize that would be a smart thing to do, but right now, I'm really reluctant to take a (good) running car, and take it apart to test parts on something else. It's one of those irrational fears that it won't run as well when i put it back on the Vette.

-Dave

Part of me is thinking that the 750/770 is way too big for that motor. That being said, if those are vacuum secondary carbs, you might need to slow down the secondary engagement a lot. Quadrajets have this setup that allows you to adjust the tension on the secondary flap so it will open RIGHT NOW or not until you get into the RPMS.

I ran a 750 on my 455 and I know I had jetting that was too big so I had to cut it back a little. That 350 should be running a good 650 IMO.

I'll be running around this weekend if you want me to bring the jets back.

-BP

If you're within 5-10 minutes, sure, drop them off. I don't need them, dont go out of your way. I'm just happy to know where they are.

-Dave

Well, I made an interesting score online, in the thirdgen.org classifieds. I found a set of new-never-used .030-over forged pistons for my 400. They're dished, so it'll lower the compression from the current 11.3:1 to somewhere around 10:1. I took a gamble that they'll work for me, $160.

The cool part is, look where they were made!

Yes, it is a good find!

TireSmoker wrote:The cool part is, look where they were made!

All us TRW alumni, are saying... "Cool...."

I still love TRW!

That's a good deal!