spread bore carb to square bore intake
 

what the phuck should i use to adapt my qjet to my edelbrock performer rpm intake? all i can find is stuff for single plane intakes

You shouldn't. You should get square bore carb. The adapters hurt performance a lot.

I agree...dump the q-jet

how do the carb adapters hurt performance? I found this one and it looks to be ok.

http://www.summitracing.com/parts/SUM-G1401/

or any suggestions on a 650 cfm squarebore marine carb would be helpful, something that doesnt require a lot of mods to make it work correctly, i have heard horror stories about stuff not fitting right

That one may be ok. A lot of the ones I have seen have a funky offset.

would not worry about the adapter as much as the q-jet hurting performance ...and if it does not have a elec choke as most do not..GFL there...

I just ordered 2 Barry Grant marine carbs off e-bay they're pricey but totally worth it and they look awesome

We have the adapter also if you end up needing it......

http://www.cpperformance.com/p-13329...r-adapter.aspx

Fixx
 

i dont know it you have thease http://compare.ebay.com/future/39024...=263602_304672 But if it is the one in the pic shown you dont need a adaptor, the intake is drilled for both a 4150 and a q-jet..

that is the intake i have but mine is the 7116 vortec version which is only square bore

fixx
 

so you have small blocks?

i have a pair of holley's 650's..

decided to go with a 650 cfm speed marine demon w/vacuum secondaries. dont really wanna cough up the coins but i guess we all know what boat stands for

Bust Out Another Thousand

should of done mechanical secondaries. you may play hell getting them to work right.

havent ordered it yet, whats the issue with the vac 2nd's?

Fixx
 

good luck with that carb.........

is the demon a bad choice?? its really my only choice without jumping to a 750 or using an adapter plate

Fix,

i know you said a 750 is what i need but im still leery of it being to much. im at 3300 ft above sea level and im just thinking its gonna load up unless im wide open all the time

Your Q-jet will work fine with the edelbrock 4 hole adapter, but I would probably just buy a new carb. There's no problem running a vac secondary but I wouldn't get that one. The edelbrock marine carb is cheap and will work great for your app. You could make the 600 work or the 750..

whats the problem with the demons?? what if i went with a mech secondary instead

No problem with the Sea Deamons at all. They are a good carb. I would also go with mechanical secondaries though. Its easier to control when the secondaries open and is based on where you push the throttle and not on the amount of vacuum.

Fixx
 

what griff said, i also like the control my secondarys,,i didnt know you were @ 3300 ft so like suggested 650 cfm with mechanical secondary's with the easy idle circuit..

call 706-864-8544 ask for scott,tell him Bill from team midnite told you to call him...tell him your engines specs and he will build you a carb and mabe give you racers net on the carb..

we use their king demon series on one of the race cars..

I guess everyone's entitled to their opinion.. Either of you guys do any back to back dyno testing with a demon or tune one in a boat with an O2 sensor?.. Before you spend any money you should call Patrick at Prosytems. He can build you a custom carb specifically for your combination and altitude for close to the same price as an off the shelf one. Also, vac secondary carbs are very easy to tune and give you the ability to really broaden the range of your primary circuit for better fuel economy at cruise. Vac or mechanical really depends on how you run your boat. If you're really gettin after it all the time or throtlling lot's through waves I'd go mechanical. My .02

ok im really confused now, lol!! let me explain the boat, the engine, where it is run, and how it is run before we go any further.

Boat is 1987 Concord Magnum II
http://www.concordboats.com/Magnum-II.html

The engine that I am building can be seen here
http://www.offshoreonly.com/forums/d...under-way.html

(Im shooting for 5200 or so rpms from this thing, cam profile is maxed at 5400)

the lake we are on 99.9% of the time here
http://www.flattoplake.org

and the usage is as follows:

I am married with two kids (girl is 3, boy is 2) so when kids are in the boat i dont like to run fast just for safety sake, same goes for wife but only cause she *****es when I open it up

60% of the time we cruising around between 35 and 40 enjoying the breeze

20% of the time we are just idling around or parked at the swimming hole.

10% its just the wife and I and no kids and I can wind it up a little bit but not much

10% I kick her ass out and run it for all its worth and race with my buddies for a few laps

100% of the time I am drinking Bud Light :drink::drink::drink:

so with all that said, what carb would be best? I want something that will be reliable for family time, but dont want to sacrifice a lot of top end performance either.

by the way, I thank everybody for their input to this thread, couldnt do it without you guys

I think you'll be fine with any of the carbs mentioned.. If you wanna go budget the edelbrock is hard to beat and won't let you down. I don't think you'll see any appreciable gains between any of them so use the one that is the easiest to retrofit and works with your budget.. :drink: