[tremo]

Hey all,

Wanted to gather some user experience before contacting Holley for advice.

Have a fresh RA-IV-spec 400ci with the goodies listed in my sig. I've changed the factory jets from #70's to #67's (one jet size down for every 2000' in elevation, per Holley), adjusted the float levels properly, and after much testing I changed the secondary spring to "Purple" (from "Plain", although mine had a "Black" spring installed from the factory). The spring change helped at the top end (above ~2500 rpm), but...

I reek like exhaust, can smell gas with the hood closed (engine off) after returning from a 15-20 minute drive, and it's hard to start afterwards. Once started again, the engine runs "well", but I can't help but feel I have some horsepower left on the table since the carb seems out of whack.

It's sitting on a factory cast iron spreadbore manifold with a Holley adaptor plate (yuk).

What else do I need to change for this altitude so gas isn't pooling (?) after shutting her off and perhaps gain some more power? Change the primary squitters? Accelerator pump adjustments?

I'd rather not have to buy a new manifold (Edelbrock Performer #2156) if I can avoid it by adjusting the carb.

Any help would be appreciated!

Jim.

[BVR421]

carefully readjust the float level to just below the sight plug

what is the fuel pressure? adjust for 6psi

[tremo]

Originally Posted by BVR421

carefully readjust the float level to just below the sight plug

what is the fuel pressure? adjust for 6psi

OK, thanks! Since it's been awhile I'll re-check the floats to ensure they are below the sight plug (they were the last time I did it).

Now, the fuel pressure is interesting. The first fuel pressure gauge I got from Summit (SUM-800215) was erractic and would sometimes show 3lbs, other times 6lbs and sometimes 0lbs.

Summit replaced it and the new one does the same thing! i.e. Engine running 3lbs, turn it off, start it, 6lbs. Turn if off, start it, 0lbs. It's inconsistant. I installed a Holley Fuel Pressure regulator and using the questionable (?) gauge that looked to be reading accurately at the time, I adjusted it to 6lbs. Awhile ago my mechanic verified it with another gauge and it looked good.

However, I did make some adjustsments afterwards using my gauge since it was reading like 12lbs (I figured the higher pressure may be the problem?) and the pressure regulator set screw was adjusted in pretty far. I backed it off to 6lbs and have since left it alone. Even before I installed the regulator though, it's always had a residual fuel smell after sitting for 15-20 minutes.

Any other ideas?

Thanks,

Jim.

[RAIV55]

Originally Posted by tremo

Awhile ago my mechanic verified it with another gauge and it looked good. Even before I installed the regulator though, it's always had a residual fuel smell after sitting for 15-20 minutes. Any other ideas? Thanks,
Jim.

Previously was going to suggest you check the pressure guage, guess you covered that. Regulators that are deadheadded tend to creep on the pressure setting during times of low fuel consumption. Adjusting don't usually cure this, make sure you have the required pressure under high load conditions. To cure the pressure creep I'd install a return line with a .060 orfice. This will help you in two ways, first it will remove pressure from the carb while the engine isn't running and secondly it will supply some flow through the regulator to stablize fuel pressure.

If the carb itself is causing the pooling problem... check the needles to see if they are sealing (float levels aren't rising while sitting). Check the power valve, if it's blown it will cause an over rich condition thru the entire operating range plus could empty the bowls while sitting. If seen bad metering block gaskets give grief and also seen pourus castings give similar symptoms.

Good luck in your search.

[tremo]

Thanks RAIV! A few things:

- I'll check the needles to ensure they are seating properly. Good tip.

- I replaced the Power Valve over the summer to try and eliminate a bog off the line. No change there, but fiddling with the secondary vacuum spring seems to have resolved the issue. I replaced the PV with a #65, same as the one from the factory. Would a different Power Valve help at my altitude???

- Where would a return line go from/to? I'm using the stock (new) mechanical fuel pump and I don't believe it has a provision for a return line?

- As I mentioned, the carb is new so I haven't touched the metering block. (Not even sure where it is on this carb and the included manual doesn't show it?) I did however replace the bowl gaskets after replacing the power valve as I had a small leak. Afterwards I found a washer that had slipped off the long bolt, but I left the new gaskets in anyway.

- I'm using an adaptor plate (HLY-17-6) to mate to the stock cast iron manifold. Could this be causing some issues, either with the fuel "pooling" or perhaps my lack of performance? I mean, this is a fresh motor and I can not get the tires to break lose from a dead stop. Something is amiss and I think the problem lies in the carb.

Thanks!

Jim.

[tremo]

A few thoughts/questions...

Depsite Holley selling the square-bore to spread-bore adaptor plate I referenced below, their included manual states:

"These carburetors have been designed and calibrated as a universal replacement carburetor for passenger cars and light truck applications equipped with V-6 and V-8 engines. It is designed for use on “square” flange intake manifolds. Carburetor adapters are not recommended to adapt to “spread” bore intake manifolds, since adapters may have an adverse affect on cylinder-to-cylinder distribution and ultimately, total engine performance. However, some manifolds may be universal (such as Weiand 8004). Please check with Holley’s Technical Service Department if you have any questions."

Q1: If I remove the adaptor plate, will the Holley bolt up to my factory spread-bore manifold? (I can't recall checking to see if it would line up when I put the carb on last spring. I just used the adaptor plate from the get-go as I ASSumed I had to).

Q2: If it does bolt up, will it cause any problems going from the Holley's square-bore to those huge secondaries on the factory manifold? (Perhaps leakage out of the sides of the carb gasket?)

Q3: Has anyone bolted on a Holley 750 square-bore to a factory manifold w/o an adaptor plate? Any problems?

I sure would like to ditch the adaptor plate without having to get a new Edelbrock (2156) manifold.

Thanks!

Jim.

[tremo]

Originally Posted by tremo

...
Q3: Has anyone bolted on a Holley 750 square-bore to a factory manifold w/o an adaptor plate? Any problems?
...

Well, after further digging, I found the answer re the adaptor plate:

Adaptor for Holley to stock 67 manifold?

Cliff's reply pretty much sums it up:

"The factory intake is an EXCELLENT performance part. There's a pretty big missmatch using a square flange carburetor on a spread bore intake with an adapter. I remember back in the 70's we used to install Holley carbs/adapters on our factory iron intakes, put the stickers in the window, use twice as much fuel and go SLOWER!......Cliff"

I believe the adaptor plate could be the primary cause of my lack of performance and I have two options:

1) Rebuild a '70 Q-Jet (Chevy version) in storage and use it on my existing stock manifold. (Less work).

2) Get an Edelbrock Performer or RPM and continue to use the Holley. (More work - drain the cooling system, pull the old manifold, etc., etc).

I think I'll see what it'll take for my mechanic to rebuild the Q-Jet...

Jim.

[RAIV55]

Tremo, if you are going to stick with the existing manifold I'd definately chose the Q-jet. My experiences trying to adapt a 4150 series Holley to a spreadbore manifold has left much to be desired in the performance dept.

The fuel pooling is another issue in my opinion.

Concerning the return line it runs from the carb. side of the regulator back to the fuel tank.

I've used 6.5 power valves at altitudes similar to yours.

[tremo]

Thanks RAIV, sound advice. I'm heading over to my mechanics (boy, I love "working" from home!) and we'll see if this is a big-block Chevy Q-Jet with the larger metering rods, etc. If not, I have a handle on one at a local salvage yard.

I agree, the fuel pooling is another issue entirely. But if I'm gonna go w/ the Q-Jet, I won't pursue it. If the Q-Jet doesn't work out, I'll revisit it with Holley Tech. Support to gather their input and then look at a new manifold.

BTW, for my motor (the car sees 80% street / 20% strip during the season), would you recommend the Performer (which to me seems like a "direct replacement" for the factory manifold? i.e. No real gain in performance) or the RPM, which could provide some nice gains with the Holley?

Thanks for update on the return line and it's good to know you've had success with the 6.5 PV at altitudes similar to mine.

Thanks again!

Jim.

[RAIV55]

If changing the manifold I'd pick the RPM.

[Johnny406]

I see you're in Colorado as am I. I have a Holey Street Dominator (low profile single plane) if you're interested. It worked great on my old 455. I raced it a lot in Pueblo with both a 750 vac and 700 DP.

[tremo]

Thanks Johnny! Hmmm...which model is your Street Dominator? Is it the HLY-300-14? Summit shows this as the only single-plane Dominator, but it fits Dodge, Chyrsler and Plymouth only??? Let me know what you want for it. Please feel free to e-mail me at info@ramairperformance.com.

Update
Adjusted the float levels last night and while the primary side was fine (just under the site hole), the secondary side was too high (middle of site hole). I adjusted it down, took my 7yr old daughter for a test drive/out to dinner and it seems a bit better. After ~15 minutes, I went back out to the parking lot to test my fuel "pooling" issue and while it started hard, it wasn't as bad. (2 times cranking vs. 3+ before). I was also able to get some rubber from a stand-still and power braking (although the vacuum secondaries should not have an affect off the line). I don't know..seems better crusing and stomping on it at 2000-3000rpm.

Brought my Q-Jet in to my mechanic and it's junk; missing parts, bent metering rods, etc. He gave me a Holley small spread-bore list #4668 as a test (#4668 is not shown in any current Holley book or on their web site).

Got a new base gasket at Napa and they said nearest they could tell it goes to a '71 Chrysler 383ci and it's probably not more than 600cfm. My mechanic believes it's a 650cfm. At any rate, from some measurements before pulling my old carb it looks like I'll still need the adaptor plate. The plan is to swap the carb only to see how well she performs. (I want some serious rubber, man!) Perhaps my current 750cfm is simply too big for my motor (not sure if I believe that yet)? TBD.

More later and Happy Thanksgiving all!

Thanks,

Jim.

[BILTIT]

I have my 3310 holley bolted on to a spreadbore e-rpm intake (no adapter)and it works fine, just be sure you have a good gasket.

[tremo]

Originally Posted by BILTIT

I have my 3310 holley bolted on to a spreadbore e-rpm intake (no adapter)and it works fine, just be sure you have a good gasket.

Thanks Biltit! Good to know the 3310 and the RPM are a good combo.

Despite having to run the adaptor plate, I ain't quite ready to give up the stock manifold just yet. We'll see if a different (smaller) carb shows better results. If so, I'll probably look for a suitable Q-Jet to rebuild. I figured it out and it's roughly the same cost if I rebuild a Q-Jet or change the manifold, but the former is less involved.

I'm off to the garage to swap carbs...

Jim.

[shaker455]

Jim,
Let me know how you make out with you Holley as I'm sure it can perform the way you would like it to.

It may need to be tweeked.
Jeff

[tremo]

Cool, thanks Jeff! Yeah, I'd like to keep the 750cfm on and feel there are some things left to tune, but using the smaller carb is a good first test.

Update
Slapped on the ol' Chrysler 383ci 600cfm Holley (with adaptor plate) and she wouldn't start and leaked like a sieve out the primary bowl. Pulled it and cleaned the needle valve, slapped it together and it started but leaked out the secondary bowl! Did the same and she finally started. Had to bump the curb idle screw all the way to keep it running when I dropped it into gear. After some idle mixture adjustments, I took it for a test drive and she's a lot more snappier (better throttle response) and seems to run smoother, but still no rubber off the line.

Talked to my mechanic and I had noticed it had #64 jets in it so I'm gonna bump these up to #68's (could fix the idle in gear problem?), replace the primary bowl gasket (still have a leak out the top of bowl but it's not near the gasket so I'll check the float level) and give it a go. I'll then adjust the timing once I see what the jet change does.

Oh, and the car starts easier too. After 15-20 minutes I went back out to the garage, reached in, turned the key and she fired right up. No fuel pooling!

Glad she's running and we'll see what tomorrow's fine tuning brings...

Thanks for all the help!

Jim.

[tremo]

Update
Changed over to #68 jets on the smaller 600cfm Holley and didn't notice much of an improvement. So, I moved on to checking the timing.

I only have a basic timing light (no dial to indicate initial and total timing) so as a baseline I marked the distributor and made some eye-ball measurements of where the current timing mark was (which was way past the numbers on the water pump housing). I then retarded the distributor (CCW) about ~1/4" and took her for a test drive. Nice improvement! Could get the tires to break loose a bit while power braking and the temp dropped 5 degrees from 210 to 205. (I plan to drop the thermostat from my 190 to a 180 next).

Test #2: I moved it ~1/8" and now things really improved. Power breaking laid a patch twice as long.

Test #3: Moved it another ~1/8" and the crankshaft mark is now much closer to 15 degrees, which is the initial timing for the RAIV per my '69 shop manual.

Found a nice back road, spooled her up to ~1500 RPM and the tires started breaking lose. Let go of the brake and laid a ~40' patch of rubber! She does REAL WELL stabbing the throttle on right hand turns too! First time I've been sideways in this car with the new motor. Felt great!

Next step is to retard the timing to 15 degrees (the last hash mark) and see how she does. Then I'll swap back to my 750cfm and see how it does now that the timing is in order.

shaker455, if it doesn't perform as well as the smaller carb, I'll drop you a line for some pointers on what to do to get the 750cfm working better. I know it can perform well on this motor (even if I have to "dial it down"), I'm just not sure what to tweak next. Also want to get rid of the "fuel pooling" issue so she starts easier.

Thanks!

Jim.

[shaker455]

Jim,
You have a PM

I'm watching your results and so far with your timming experment it looks like things are getting better!...very good!

I'd say invest in a good light that also has a tach besides a timming dial as your seeing now the dist and carb work together...I think Autozone has Actron brand with all those features for $100.

Touching on a few other subject you discussed eariler I would advise you to upgrade to the RPM intake.

I have it on my car and besides the performance improvement you have the ability to go from spreadbore to squarebore configured carbs to see for yourself what type you like best.

I realize it's time and money but the gains are worth the effort.

[Tom Vaught]

I would be very careful about doing a lot of power runs with not actually knowing where the timing really is. Good way have to replace pistons.

JMO

Tom V.

[tremo]

Thanks Tom, very good advice. I'm gonna look for a good timing light, something I've wanted to get for a quite awhile.

Ever since my engine build the timing has always been whacky. The initial reading has never lined up with the numbers on the water pump housing no matter how many times we pulled, slightly moved, and reseated the distributor.

I can't seem to find my notes, but when using my friends timing light I recall the total timing ended up being like 76 degrees @ 2500 RPM. Which I beleive is approx. +30 degrees higher than norm for this engine?? I don't know, perhaps the #1 cylinder wasn't at TDC when my mechanic lined things up? Not sure.

Anyway, along with not having a good timing light, this issue compounds the problem. However, let's say I get a new light and the total timing is at ~60 degrees after my recent adjustments. Is this OK? Since I can't use the original Pontiac specs as a baseline, how do I know which timing for my engine is good/bad? Do a vacuum test perhaps? Use the seat of my pants like I've been doing, etc?

Thanks all! The input is much appreciated...

Jim.

P.S. I'm working with shaker455 offline on my HEI weights, springs, etc.