heres an initial review of the summit 600 cfm vs.\


install was easy 3rd one of these carbs ive bought

If your going from a street demon or edelbroke to the summit holley you will need a throttle cable bracket.

initial start up was great once i tuned the idle screw to 800 rpm.
i have the idle air screws 2.5 turns out both side ( running a 2 inch spacer my 1.5 plus the supplied spacer gasket made of wood i believe) the fuel rail was easy to install i used plenty of Teflon tape on the fuel fittings.the throttle cable needed no adjustment i also installed a quick change vs kit drive ability is great now that it is tuned. The throttle response is great and the car idles well the carb has been on 1 day i will update this in a week with an mpg update so far its matching or exceeding the demon in drive ability and ease of tuning . as stated before ive had these carbs before on the same engine and theyre a good value at 289.99

any questions about this or the demon 625 feel free to ask

 

I’m wondering how you can comment on its tunability when all you do is set the idle speed and idle mixture.

 

i'm taking the high road on this 1 i've had these carbs before and there easyly tunable the jets are spot on all i had to do was set the idle speed mix choke and change the secondary spring to my liking if you would like to donate the gauges to tune it to the letter ill be happy to do that

 

I getcha. But my point is that what you did was very basic, something most anyone with any amount of knowledge and the ability to read can do.
And at this time I think it’s safe to say you were fortunate to have a combination that was close to what that carb was jetted for. Wound you agree?

 

i wouldnt say fortunate i would say prepared ive got jets on hand but i tune mine by reading the plugs and listening to what the engine likes u can have high vacuum and poor idle so i go the old way of tuning

 

Aren't those flare fittings? If so, no need for thread sealant as the fittings seal at the flare interface, not the threads as a pipe fitting does.

 

they are but i put a little teflon tape on the threads i dont 100 percent trust flares on the rail the 1st one i bought wouldnt seal w/o tape

 

Just because it works well does snot make it good , I have a 750 holley dp that works great out the box on my 355 but leaves much to be desired to someone who knows carbs.

 

The threads have absolutely nothing to do with sealing.

 

So you can tell if it’s going mildly richer or leaner at the END of the power band by reading plugs? Or even how flat or not your fuel curve is throughout? That’s bs, you can’t. You don't have enough time to get color on the plug at that point.

If you want to over simplify this that’s fine. But don't make it out to be some in-depth extensive tuning session because at this point, it’s not.
Sorry.

 

Some people experience that "lubrication" of the threads assists in seating the flare. Teflon can provide that lube effect. Maybe that's why the OP had success with it.

FWIW: As for the Summit Carb. Everyone I know that uses one is very satisfied with it because it requires no tuning for general street use. Perhaps because it's set up on the rich side - I don't know. I use a 750 CFM one on my 427 gasser and it has been trouble free and performs better at the track than 3 other typical Holleys that I tried.

 

OK, that is a logical explanation if the threaded parts don't go together smoothly. I have never experienced that, but it makes sense.

 

This thread is a disaster

 

:d

 

if you read the post that was just an initial post im going to update it once the carb has been on the car awhile. and stop trying to start a pissing match no 2 of us tune our engines the same way we all were taught different and if our cars run to our liking then so be it im not the best carb tuner but i sure as hell aint the worst i do what i can on the budget im on and when i have time i agree vacuum gauges and afr meters are the best way to tune a carb or any fuel set up but i have bills that come before my car so the tuning equip isnt in the budget

 

the teflon is optional i do it out of habit more then anything nut hey if it works use it

 

Dude you cant argue simple engine theory. carb tuning and getting it to run are two different things. Those summit carbs are an old junk *** holley design they don't even make anymore .

Further more you claim the jets be spot on .... How do you know that ? Just because it runs good does not mean its running at optimum performance which will balance both MPG and MPH for HP etc etc.

 

im not arguing engine theory . and i know the summit carbs are a holley design for me they work decent and i havent even filled up yet to test mpg and i dont have a test facility near me i'm doing what i can to keep the car olds powered but a 454 bbc is starting to look better and i agree just because it works well doesnt make it optimun but not everyone has the budget or time to nitpick

 

I usually work on a shoe string budget . On the carb end my tuning is minimal but I know there is lots to be desired. But it works. Working and working efficiently are 2 things. Again I'm not splitting hairs because I know all about working on a tight budget but then again I don try to church up anything I'm using because my holley on my 355 is box stock aside from flipping the pump cam that came with it but its a far cry from using it to its potential on both ends. I have good e/t and mph times but there is still plenty to tap into. At this point the carb I'm using just work but it does not make it good. I haven't even made a jet change on it.

 

mine gets me to work church college and home so i dont have to time to tune it like id like to