That's awesome to see someone else exercising the same trick I've been doing for years! It's how i got those 390/428 GT Holley carbs (780cfm) to behave on my small blocks! It works! I just wish that secondary set screw was more accessible! Usually a 1/4- 1/2 turn did the trick. I just hate drilling shit because it renders the carb useless to put on anything else without replacing the driled parts. That Summit carb you got there is/was a Holley, it was initially designed by Holley as a spin on the Autolite 4100. For whatever reason it wasn't working for them and Summit bought the design and was able to sort out it's issues. I hear they are pretty good carbs. Great video fellas!
@@CCAutoWorks I think giving Edelbrock a run for its money was in the plans with this design. The Autolite 4100 was a bad ass carb, it just never caught on with the aftermarket since at that time Holley was overshadowing almost everyone.
Chris you could always bump the timing up a little and another trick I’ve done is drill out the idle air bleed to get more air into the idle circet and I’ve also drilled holes in the front throttle blades to let air in and be able to close the blade to square up the transfer slots, just trying to help out with some old school tricks lol , keep up the great work 💪
Advancing the timing would help in more then one way probably but I'm already at 13° initial hate to go anymore with the fuel we have available here and the drilling trick works great I do that on the Edelbrock carbs thanks for the info I'll look into the idle air bleeds
Yessir it's basically the same concept as a two or four barrel idle screw mixture screw accelerator pump adjustment more less depending on engine needs
@@CCAutoWorks I’m not sure 🤔 the guy said it had 14.5 to 1 compression so if true we need a big one maybe a 900 or something but we have a 750 double pumper right now
Wow that is a weird carb. I have a Holley 850 double pumper on my sbc 383 and it works great. It took a little tinkering but I finally got it dialed in very nice. What are the cam type and specs you are running? Mine is a hydraulic roller with .550" in/.546" exhaust with 202°in./212°ex. duration @ .050". Idle to 5,000 RPM advertised but pulls to 6,000. With that cam I get 22 inches of vacuum at idle so I run a 10.5 power valve because they don't make an 11. I can't recall what the jet sizes I used. All of the dual plane RPM Airgap style intakes flow around 220 unported cfm so it doesn't matter how big the carb is because you're only going to get 220 cfm through the intake. You just set it up accordingly.
That's a lot of info to take in an 850 wow I thought this 750 was to big thought I'd never get it to stop filing plugs the cams like 585 lift 230/236 duration and 110 LSA 7 inches of vacuum at idle sounds like u have all the vacuum
Looking good bro at least yours runs Both my fords that got 460 wont idle with edelbrock carbs cant figure it out tried everything except blowing out my fuel line 😩
@@CCAutoWorks yea i have rebuilt the carb got new fuel filter and pump checked my. Floats runs but will not idle i guess my fuel line might be plugged this problem after parking for a while
