Headers choking me off?

[Fasterthansome]

The 1/2 inch fuel line is a mechanical pump thing. Or with a big pump.

3/8 with a blue works great.

What kind of total timing you running? Is this a flat top combo?


Holley 4150 needle and seat seems good to about 7 psi max and after that is a crap shoot as far as staying seated.
I like to run 6-6.5 at idle.

[Sirshredalot]

Id say that the fuel line is adequate, 3/8 in my experience can support a car well into the 11's with a small block and single carb...Id say enough for 500hp....unless you have unruly volume demands like multiple carbs or large nitrous system.

Gearing sounds to be ok if youre at your peak through the traps.
generally youd like to be about 200rpm over peak through the lights but close is close enough.

Does it just nose over or just not have the performance youd expect?
I always recommend the larger tubes....especially in a light car.
2129's all the way....

Where does your converter stall?
What fuel pump are you running?...You should be able to run upwards of 7.5 psi. Maybe try switch your needle and seats to a higher volume set...titanium or stainless...theyre not that expensive and if it is a volume problem at the carb itself that could cure it.

How are you jetted now? Rich, lean, right on? Timing?

I think you could be in the 11's with a tune up....but thats just me.

God bless
-Shred

[Fasterthansome]

I have 2 cars I work on running blues with 3/8 line and running mid 10's the other running high 10's.
Both are set up 3/8 to reg and one line from reg to carb other to fuel solenoid. Idle pressure set at 6.5 and drops a tad when spraying ( to where I want it)but stays constant.

[mldeolde]

just a thought Josh but if you are only reving it to 5800 rpm in the traps i think that the size of the 2129's is way more than you need to get your engine to breath as much as it needs. it still may need gears. i would think that you should be turning at least 6500 rpm in the traps to get it done with that small of a combination. i think you have another compatability issue still hideing in there preventing the times you should be able to get out of that car with that engine.

[cjbiagi]

Josh, I wouldn't do anything to cut up your car, it is way too nice to do that too. I have seen countless number of header tests of different size header tubes and unless they are on a pretty radical engine I was never impressed that much with the change. Yeah, you might pick up 20 hp on the top, but making one change probably isn't going to drop the ET that much. I'd look elsewhere first like the fuel delivery, timing, jetting etc and overall tuning. Just my opinion, I guess it all depends upon how fast you want to go.

[spyder_xlch]

If he picks up 20 HP on top and it takes away some off the bottom he may get better traction off the line dropping his ET.

[Fasterthansome]

I think my gears are pretty good. I've got my shift light set at about 5800 rpm... which is exactly where my max power is at (I've dyno'd it). Running through the traps, I've revving high, just right before my shift light comes on.

I don't think fuel is the issue, I've got a holley blue pump, and actually I'm regulated at about 5 psi... it seems anything more and I've had trouble with fuel blowing through the needle/seat with much more than that. We'll see... I've got a memory fuel gauge... I've just never remembered to set it before I run! I'll try and do that this Friday.

And that's my biggest concern with the Hooker's... I love the Sandersons in that they go in without modification, and ground clearance is wonderful... I'm reluctant to butcher my fenderwell, but I might have to. I do have a mini-starter already though.

Thanks for the offer Bruce, I'd like to take you up on that but that's too much to ask. And if they worked, I wouldn't want to have to take them off to put my set on! I'll just have to keep my eyes out for a good used set.

What kind of fuel gauge are you using?
Why are you shifting as soon as you hit peak power? What are your cam specs?? What do you run your total timing at? What total timing have you tried up or down and what was the effect on mph?

[mldeolde]

my recomendation- as if you haven't gotten enough already - is to fid a deal on an edelbrock performer RPM manifold and a little more cam like the 480/280 comp cam i had in the Nova. any morre cam than that and you may have to run a vaccume canister to get enough suck to get that th350 to shiftout of first gear

[heinz057]

josh why don't you run this buy the guys at speed talk

[chevyart]

seems all of us guys are preety close to each other with our suggestions. one more thought. is it possible that your converter is slipping on top end. this will kill your time and speed on top end. Also you say you are coming through at 5800rpms. that is nothing for a small block, especially with those nice aluminum heads you have. you need to cam up brother. best dam hydraulic cam I ever saw, and it was trully streetable was a
crower hydraulic around 530 lift and a comfortable duration around 230 @ .050 and get that RPM air gap that one of the guys recommended with a 700-750 CFM holley and you will be screaming through the traps. I disagree with the 3/8 fuel line. 1/2 or 5/8 is better. again as i said volume and pressure are two different things. smaller line will give you pressure, but not the same volume at trap speed. call any of the carb or fuel pump companies and I bet my life they will tell you to definitely go with bigger lines(Boy thats is a bold statement, to be betting my life. good luck Chevy Art

[76Nomad]

my recomendation- as if you haven't gotten enough already - is to fid a deal on an edelbrock performer RPM manifold and a little more cam like the 480/280 comp cam i had in the Nova. any morre cam than that and you may have to run a vaccume canister to get enough suck to get that th350 to shiftout of first gear

I've got a friend wanting to sell a Wiend Team-G aluminum dual plane high rise intake manifold off his 350. Not sure how much he is asking but I can find out if anyone is interested.

I doubt your headers are slowing you down up top. My friend has 1-3/4 primaries on his Cobalt and he was able to walk away from a 298whp SRT-4...before he broke a ringland.

[v8astregt]

Wow, many responses! I'm beat, don't think I'll get to all of them tonight. But I'll do what I can.


The cam is only a 268HXE, peak power is at 5800, and I do have the shift light set for that but that gives me a couple hundred rpm before it actually shifts (human/mechanical delay), I've actually hit the 6200 rpm rev-limiter before. I don't want to run higher than that because I have stock-type valvesprings, and I throw belts higher than that.

I do have a Performer RPM intake. If I do anything with that, I'd actually look to a single-plane intake... from what I hear I can go either way with this cam.

As far as whether or not I'm getting fuel... come to think of it, there was an A/F reading on the dyno chart from a few months back. Looking at it, I was running 13-13.5:1, so I'm not far off. It was a hair lean, but I've jetted it up two sizes since then. Should be good, but haven't dynoed it since.

As far as my fuel gauge... first I had a crappy little Jegs mechanical that worked for an hour. Now I have a $300 Autometer Sport Comp with memory... which I'll probably try to remember to actually use tonight!

I've got some of the parts to make a revving motor, but with the valvesprings and cam I have, I don't imagine anything higher than 6200 would benefit me. That's part of the issue I'm debating with the Hooker's. After emissions next January, I'm thinking of going up a couple cam sizes, upgrading valvesprings, changing the intake, so forth. I'm thinking THEN I might have too small of a header.

I don't know the specs on my converter, only that "it's a couple hundred rpm higher than stock", that's all I know. That would be something "in line" for an upgrade, but not high on the list.

Also, speaking of changing things, I don't want to get rid of my 3.73's. I'm running about 5800 through the traps, I know 4.11's would help me there, but that would kill any streetability I have now! I can barely drive the freeway as it is!

-76Nomad... your buddy's Cobalt is running 1 3/4" primaries? That bigger than I've got! I'm only running 1.5" with the Sandersons!

Thanks for the ideas so far. At the track tomorrow, I'll remember to record the fuel readings, and I'll play around with that. Also, I have not timed my car in literally two years. I can't even remember what it's at. Is there a good way, or maybe a site that can explain it better, on the best way to time at the track? I haven't played with timing at all. Another thing on my "list", lol!

[Fasterthansome]

I disagree with the 3/8 fuel line. 1/2 or 5/8 is better. again as i said volume and pressure are two different things. smaller line will give you pressure, but not the same volume at trap speed. call any of the carb or fuel pump companies and I bet my life they will tell you to definitely go with bigger lines(Boy thats is a bold statement, to be betting my life. good luck Chevy Art

In his application a Blue with a 3/8" line isenough to supply his combo.
There is no need to spend the time or $ upgrading the line size at this point.

I have no idea what a fuel pump manufacturer would say I only know what I have seen in actual flow testing of fuel systems.

[Fasterthansome]

Also, I have not timed my car in literally two years. I can't even remember what it's at. Is there a good way, or maybe a site that can explain it better, on the best way to time at the track? I haven't played with timing at all. Another thing on my "list", lol!

I would check wide open throttle, fuel pressure, float level.

This is where I would start before I spent a nickle on anything else. I would check total timing.


I would then check to see what springs are in the distributor(color)might help.
Do you have a curve kit or some light springs?
Do you have an HEI distributor?

[gerbsinmd]

Josh, when I run the quarter we unplug the vac advance and jump the timing up from 10 btdc to 24 btdc, it wakes my dads 383 up quite a bit.