[gold bird]

well got to the track last night ,and did so so. my combo is a 400 block with 455 crank stock rods and std. 455 speed pro l2359f pistons , rpm intake lanati cam 230/230 490 /490 ,1.52 comp roller lifters , 6x/8 heads 40 shaved off, out box 750 holly dp. . first pass was a long wait and i let the car run so it was not to cold 140 temp seem to have a dead spot free reving it. well it fell on its face just like turning the key off. then it took off . tryed it at 170 temp and still there so must have some trash in it. what jets should i run in holly 750 dp. front and back ? has the 4 corner idle out of box jets .allso i run 93 pump gas 35 total timing. 3.73 with 28 10.5 mt drag slicks 14. psi


60 foot 1.785 60 foot 1.767
330 5.313 330 5.263
1/8 8.287 1/8 8.235
mph 82.55 mph 82.22
1000 10.881 1000 10.838
1/4 13.088 1/4 13.052
mph 101.11 mph 100.80

[Jagtec1]

I ran between 72/82, and 76/84 on my Proform main bodied 750. I ran no rear PV, and a 3.5 in the front. I had 35 squirters in both front and rear. Best time was in my Sig.

Try a bigger squirter...and you can play around with the pump cams. I had 30/50cc pumps on mine.

[gold bird]

thanks jegtec1 i will try a bigger squirter and cheak my jets.

[screamingchief]

I agree,I would try playing with the squirter size first,was going to post that but when I logged in I had a PM to answer,so jagtec beat me to that.

I almost always have to run at least a 31 squirter nozzle on most of my pontiacs,often more.

The 50cc squirter pump kit can help those cars that want a big/long shot too.

Also might be a good idea to put some secondary jet extensions (I like the screw in ones) and a notched float in the secondary side to keep those jets in the fuel on a hard launch.

And I usually set the secondary float level a little higher too.

Also make sure you have the plastic vent whistle on the primary side.

I never run a secondary PV,though I dont believe the 750's have them to begin with,so you should be good there.

What is the supply side of the fuel system consist of?

Tank/cell,pumps,filters,lines etc.?

[Jagtec1]

Oh, yeah...I did run the jet extensions! You definately need them. You may need to change out the float to a notched nitrophyl type.

[gold bird]

screamingchief ,jagtec1,thanks for the poast , and i will look at the carb sunday i just got in ,from a trip to georgia , my brother swaped his car for a dragster .rollin chasis. drove all day . thanks jesse.

[gold bird]

squirter size in front 28 back 31 . should i go 31/31? i still have to take off the carb and look at jet size. and look for any junk that may have got in it , i have a holly red pump 5 to 6 psi. one paper filter up front and a glass one befor pump in the back.stock lines and gas tank . all ruber has ben replaced . thanks jess.

[Jagtec1]

Presursor: I'm no carb expert!

I'd set pressure at a solid 6-7 psi ( I ran 7). I'd try at least 31/31 squirters...maybe bigger...you'll have to experiment and see what it likes.

If you have not torn the carb down to clean it from when it was new, it would be a good idea, as there is often junk in them out of the box.

Make sure the float level is set properly, or you may be running out of fuel.

I'm betting the squirter change will get you better response off the line!

[gold bird]

hey jagtec1 thanks never had it apart on the 400 it was a bolt on ran good but alot of changes to 455 pump is holly red box said only puts out up to 7 no reg needed most i have had was 6.5 all new and not alot of time on it . so time to go blue ? this is a steert car allso i just like to go and have fun at the track alot . 3640 with me in it 1.7s 60 foot was cool but was falling on its face so maby 1.6s. The mph was 82 1/8 100. to 101 1/4 on the street it is hard to get the dead spot it spins bad and you canot punch it hard unless you want to hit the revlimit 5400 . shift at 4900/ 5000? thanks

[Jagtec1]

I'd keep the R's down with the stock rods. I use a Holley black pump with a big port regulator, and have no experience with the red or blue. I think it may be a bit small for your setup. I'm sure others can add more info/ experience on that!

[gold bird]

yes i will i have the msd set at 5400 it is a dial box not the chip ,5200 /5400. just called my brother and he has a 31 with the brass tubes . going to take it off and look at it . nice day out ,thanks for your help.

[Pat 79 T/A]

Also check your acc. pumps for proper linkage adj. Did you look in carb. to see if all acc. are shooting equally smooth? Is flat spot coming from idle to wot. or are you loading engine then wot? Did you try 37deg. timing or any other to see if it changed free load bog?

[screamingchief]

Loose the glass filter before the pump in the back immediately !

Those are enough of a restriction on the pressure side,cant think how bad that must be on the suction side of an electric pump...

Try to get a high flow filter back there,something with a stainless mesh element,or possibly a sintered bronze element.

Use a filter with very little resistance to flow,electric pumps are good pushers,but are terrible at "sucking".

This is especially important if you drawing fuel thru the stock pick-up...

JMO/FWIW.

[Jagtec1]

I use a BG5000 filter before the pump.

[gold bird]

thanks to all and i will get rid of the glass filters and still have to take the carb off . got the 31 squarter and gong to try it on the street. bog with mor timeing and less worm cold off idle on converter. had 5 passes and all night in staging it was not a good thursday night . but it was first time back and new combo so any day to me at the track is fun so can be to upset . i think a mid 12 will be all it has . that is fine with me low buck you know. i go to have a good time with my kids and family and friends. thank for good info .glass filter a no no . thats why im here to learn i will tell ya when i find the problem. thanks jesse.

[gold bird]

my front jets are 71 6.5 power valve and the back are 80 ,block off power valve that is the way it came out of the box. ? had some junk in it allso going to carb clean it and try 73/ 84 ,is that to much? 31 squirter did not help.

[Jagtec1]

Try a 35 squirter. I'd jet it at 72-74 in front and 82-84 in rear. The jets won't really solve your stumble, I don't think. Check the acc. pump adjustment and check the pump cams...you may need to change them...but I'd try a bigger squirter first. Are you having a problem from a dead stop? How are you launching the car? What gear and converter?

[gold bird]

jagtec1 i am launching the car off idle then wot. also bring it up on converter 1200 rpm. same thing but when i took it apart it had some trash in it so i will clean it good and up the jets. 2800/3000 stall and 3.73 gears 28 tall m/t drags. got a bag of jets off my brother so i will see what he has.

[gold bird]

well as i said this 750 d/p had 71/ 80 jets and a 28 squirter , so i put 73/ 84 and a 31 squirter , cleaned the carb had some trash in it .so it is not doing the dead spot off idle or while driveing at a slow speed and nailing it . can not get on it to much as the neighbors will hate me. lol. have to go to the track and see if it is good . thanks jesse

[Jagtec1]

Looks like ya got it figured out! Have fun!