What does everyone seem to be running for a carb on their SB stroker?


I have a bigs stage 5 750 on there now
I ran the car at the track this weekend and it ran 7.17 at 94 mph in the 1/8 off the trailer. got worse as the day went on track went away and air got worse. lost 2 10ths in just the 60 after the 1st run

When I got back to the pits pulled some plugs these things had no color on them at all. I started jeeting it up throughout the day. I went up 13 jets from where I was at the start of the day and it just started getting some color on the plugs.

Was just trying to get an idea of what everyone else is running for a carb on thier strokers.

Mine is a 416 with eddy heads 600 lift solid cam m1 intake 727 8 inch conveter 3.91s in the 8 3/4 275 drag radial

Thanks

Im NO expert but it could be the air-bleeds. I have the same problem with my 750dp with a pro-form body. My plugs were WHITE and I mean WHITE!!!! Called Jesse at BIGS and he sent me some air-bleeds and it fixed my problem. I had too much air and not enough fuel.

Call Jesse!!!!

I called jesse he said nothing about air bleeds

He thinks I have an intake leak or something

oh..ok....he would know.

On my 414 cid the bigger the carb the faster we went, 1050 works good

I was gonna say at least a 950.

I run a 1050 dom on my 405ci... I turn it to 8200

I must be undercarbed with my Demon 750 on a 408??

my 416 takes every bit of my 950 might like more.

13 jets ?
that's not tuning.........that's an overhaul.
If you need to go that many jets in either direction , you have done something horribly wrong with your life.
Did it keep getting quicker with each change ?
I am no Holley guru by any stretch , but I do think a 408 would want more carb and I do think that more than 4 or 5 jets change means your baseline is off by a good bit or you have other issues at work.
I'd be looking for a friend with a bigger carb to try on there first.
But if there is a problem outside the carb like an air leak.......it won't matter what you put on there.

We run a 650 DP from Bo Laws on this 427 inch stroker. Works great.

You have something really messed up if you had to change jets by 13 sizes. That sounds like you have an intake manifold leak or some other major issue.

I'm gonna look into a air leak this weekend.

If it's not a intake leak what else could it be?
besides to small of a carb.


I have ohmed all the wires none of them are over a 100 ohms. I have done a compression check 155 across the board.


My buddy has a 850 demon we are gonna put on it this weekend and see what gives


Thanks

A 750 is not too small of a carb for that engine. Lots of race engines make a lot more power with carbs that are even smaller that what you're running. You have some other problem than carb size.

what fuel line you runnin? you should have -8 line feeding that. you may be starting to run the bowls dry. i had the same problem and found it on the dyno. the other issue is using the correct heat range spark plug. a rc12yc works good in my 408. i was using a 7 ngk and it was way too hot.

I have 10 an from the tank to my aeromotive a2000 fuel pump goes 10 an up to a y that goes to a big port holley reg and 8 an to the carb

I took the 10 an that goes to the y off and let it flow into a fuel jug. I had a gallon and a half in 20 seconds which should be more then enuff fuel

I run a ngk - 7 for the motor I didn't have any -7s left new So I put a - 8 ngk in there

that sounds like plenty of fuel. whats your compression?

compression should be right around 10 to 1

i had the same problem as you with my 408 using a 1000hp. no matter how much jet i put in it i would gain less than 1 mph or less and had no color on plugs. took it to the dyno and seen first hand what was going on. the air/fuel reading looked like the spiked lines on a heart scope,not even close to being a smooth line. i had a ngk7 in it and the dyno operator thought it was too hot and even an 8 to be too hot,so he put a champion 12 in it and the air/fuel reading had a nice smooth line. i'd try a colder plug just to see. my compression is 10.5:1.