[chiphead]

OK that's interesting.

The purpose of vacuum advance is to add timing at light load (high vacuum) and reduce timing at high load (low vacuum). When the throttle is opened, vacuum drops and vacuum timing goes to 0. This reduces the chance of detonation/pinging at heavy throttle. When throttle is reduced for cruising, the vacuum advance adds timing at light load to improve MPG and light throttle response.

Typically I like Ported vacuum from a carb source, so the vacuum advance only works above idle. This results in a more stable idle, because vacuum fluctuations at idle do not impact idle timing. Having to run manifold vacuum to the vacuum advance to get the engine to idle, indicates either a lack of base mechanical timing, or too-lean idle fuel mixture, or a cam that is entirely too large for the engine size and/or compression. The cam is marginally too big at 9.3 compression. This can be mitigated by increasing compression, advancing the cam 4* and/or using Rhodes lifters. The rest of the issue is tuning, adding base timing, adding idle fuel by modifying the Q-jet's idle feed circuits..

I would not recommend throwing another carb on it, unless there is something specifically wrong with your carb. The '77-80 electric choke and APT Q-jets are easier to tune, but not required. A good Q-jet tuner could make any '70s era Q-jet work well. Q-jets are notorious for being lean in the idle circuit, so the vacuum advance could be a crutch for lean idle mixture. Going from 750 to 800 CFM isn't going to do much on a mild street motor. Be aware that if you get the TV cable adjustment wrong, the 2004R transmission can fail due to low line pressure. So pay close attention to any throttle linkage changes.

Tune, tune tune. Throwing parts at it is not a shortcut.

[petes67bird]

Here are all the specs I can locate on my motor and setup right now. This is probably all the information I currently have.

• 455 YW 485428 E174, block from 1974 bored 0.030 over, 9.3:1 CR. Block is 0.015” deck height to top of piston, compression between 159-166 on all cylinders
• 496453 Crankshaft
• Polished standard size rods and mains, resized rods with ARP bolts
• TRW Forged pistons, mahle rings
• #96 heads E171, 3 angle valve grind, milled, screw in rocker studs, new integral valve guides, new valve seals, valves ground and cut 3 angle
• Melling 26308 cam
• HT-951 Lifters
• 224-43364S oil pump
• R.A.R.E. Ram Air Manifolds, 2.5” downpipes, 2.5” exhaust, Spintech 9000 mufflers
• 1555cpa copper lead rod bearings
• Tin Indian Performance Viton rear main seal
• 160-degree thermostat
• 9799068 iron intake manifold
• 29268WF 0779 Quadrajet Carburetor
• Carter fuel pump
• GMB 13-1280 water pump
• Cold Case Radiator
• Powermaster mini high torque starter
AC Delco HEI Distributor
• Rebuilt AC Delco Alternator
• 200R4 SSR non lockup, Billet servo 2nd gear, Dual feed with new 3-2 control system, Competition Valve Body, Alto race red clutches for 3rd and 4th, 2nd reverse boost valve 0.300, line pressure boost valve 0.500, line pressure regulator spring, 10 vain rotor pump, Wide Alto red lined band, shift kit, HDS hardened stator, bearings replacing thrust washers, 4130 steel band anchor, 0.500 booster valve, triple 3rd pressure and clamping force, steel input shaft forward drum, pan spacer and 700 4R filter, long transmission cooler
• 9.5” Tri Shield performance Billet Torque Converter 2700-3000 stall
• Eaton Posi, Motive 3.73 gears

[Jay S]

Looking at the compression pumping numbers advancing the cam from straight up too 109 would help some. But I don’t know that it is actually your problem, 160 lbs should be enough, especially with a 2800 stall converter and that deep gear combo. You already have to much stall for Rhaods lifters to help with bottom end.

I have done more 96 d port head Pontiac combo’s than any there Pontiac combination, both stock and ported that flow in the 280s. That should run in the 13s pretty easy as it is, could nearly make it into the 12s with a sticky tire. The cam timing would be worth a few tenths, assuming it is correct that it is straight up now. Which judging by the pumping numbers, I don’t have any reason to question it isn’t straight up.

[petes67bird]

Originally Posted by Jay S

Looking at the compression pumping numbers advancing the cam from straight up too 109 would help some. But I don’t know that it is actually your problem, 160 lbs should be enough, especially with a 2800 stall converter and that deep gear combo. You already have to much stall for Rhaods lifters to help with bottom end.

I have done more 96 d port head Pontiac combo’s than any there Pontiac combination, both stock and ported that flow in the 280s. That should run in the 13s pretty easy as it is, could nearly make it into the 12s with a sticky tire. The cam timing would be worth a few tenths, assuming it is correct that it is straight up now. Which judging by the pumping numbers, I don’t have any reason to question it isn’t straight up.

Maybe I will tow it someplace to get tuned this winter. Couple questions.

1. Should I keep the iron intake?

2. I reached out to my carb builder and he will swap out my current quadrajet for a 800cfm carb for not too much money, he can even provide an electric choke but my manifold is setup different. Do I stay quadrajet, do I upgrade to 800cfm, or do I ditch and go edelbrock/holley?

3. Do I spend the cash to degree the cam, is the return worth it? The only benefit would be I can change the timing chain at that time as I believe its not a double roller chain.

I am just looking for the most economical way to get this engine competing with my friends. We plan on renting a drag strip this spring and they have quick street cars with a mopar 408 stroker, and some BBC builds in the mix.

[Jay S]

Originally Posted by petes67bird

Maybe I will tow it someplace to get tuned this winter. Couple questions.

1. Should I keep the iron intake?

2. I reached out to my carb builder and he will swap out my current quadrajet for a 800cfm carb for not too much money, he can even provide an electric choke but my manifold is setup different. Do I stay quadrajet, do I upgrade to 800cfm, or do I ditch and go edelbrock/holley?

3. Do I spend the cash to degree the cam, is the return worth it? The only benefit would be I can change the timing chain at that time as I believe its not a double roller chain.

I am just looking for the most economical way to get this engine competing with my friends. We plan on renting a drag strip this spring and they have quick street cars with a mopar 408 stroker, and some BBC builds in the mix.

With the pumping numbers you have, I don’t think it is worth the return unless your goal is to pick up a few tenths.

Another q jet would be worth a try to see if it wakes it up. It won’t be any quicker than a well tuned 750 though if your is working correctly. The only way I would consider switching to a holley is if you changed intakes, to a single plane. A single plan trades some low end for upper end power, it sounds like your looking for power everywhere yet. The stock intake should not be close holding it back yet. Fuel pressure gauge, AFR meter, and read the plugs are the basic tuning tools you could do without taking it to a shop. Could also try a DUI distributer if the carb doesn’t help, they are usually home runs right out of the box.

How does your car do coming up on the converter? Is it tight, and moves the car with light pedal feel?

[petes67bird]

Originally Posted by Jay S

With the pumping numbers you have, I don’t think it is worth the return unless your goal is to pick up a few tenths.

Another q jet would be worth a try to see if it wakes it up. It won’t be any quicker than a well tuned 750 though if your is working correctly. The only way I would consider switching to a holley is if you changed intakes, to a single plane. A single plan trades some low end for upper end power, it sounds like your looking for power everywhere yet. The stock intake should not be close holding it back yet. Fuel pressure gauge, AFR meter, and read the plugs are the basic tuning tools you could do without taking it to a shop. Could also try a DUI distributer if the carb doesn’t help, they are usually home runs right out of the box.

How does your car do coming up on the converter? Is it tight, and moves the car with light pedal feel?

Its a very tight converter. When Continental stopped, this is the converter Cliff recommended to me to buy. Another option is to do more head work, port the 96 heads and add roller rockers.

[Jay S]

Originally Posted by petes67bird

Its a very tight converter. When Continental stopped, this is the converter Cliff recommended to me to buy. Another option is to do more head work, port the 96 heads and add roller rockers.

A friend has that same converter in his GTO, they are nice converters.

It sounds like you’re pretty serious about making your car quicker if you have plans to go to the strip.

If you just have 1.5 rockers, you about have to take the heads off to clearance the heads for 1.65 roller rockers. Just switching to roller rockers won’t make it quicker, you have to run a larger ratio too. So at that point you may as well have someone port them and clearance the pushrods. We have 96 heads yet on our 71 T37 on a 455, started out stock and worked there way to were they are at now. They flowed in the 280s after the last time I worked on them. Which is enough flow to support 550+HP in a street engine pretty easily. Certainly easier to buy aftermarket aluminum though, but probably 3X the money if someone has already been through your heads. Around 500 HP is about the limit on a RA4 cam for a street engine no matter how good the heads are, it hard to get enough lift go much beyond that.

[petes67bird]

Originally Posted by Jay S

A friend has that same converter in his GTO, they are nice converters.

It sounds like you’re pretty serious about making your car quicker if you have plans to go to the strip.

If you just have 1.5 rockers, you about have to take the heads off to clearance the heads for 1.65 roller rockers. Just switching to roller rockers won’t make it quicker, you have to run a larger ratio too. So at that point you may as well have someone port them and clearance the pushrods. We have 96 heads yet on our 71 T37 on a 455, started out stock and worked there way to were they are at now. They flowed in the 280s after the last time I worked on them. Which is enough flow to support 550+HP in a street engine pretty easily. Certainly easier to buy aftermarket aluminum though, but probably 3X the money if someone has already been through your heads.

I will be stopping at the local racing shop in town here in about 2 hours to chat with the owner to see what he would charge for porting vs just buying new heads. Also, I do not have anyone around me that knows or will work on a quadrajet making it hard to stick with one. I want to ask him his familiarity with them and then make a decision on the intake/carb combo. Having a quadrajet is nice, but when issues arise, I do not have the expertise to troubleshoot them which makes it then a requirement to ship back and forth to the builder.

[RocktimusPryme]

I really think you could be making a mountain out of a molehill here. These threads tend to get out of hand, and Im not even saying any of it is bad advice, but I just think you should slow down and try a couple of baby steps.

Before you blow half of your fresh engine apart, I think you should just check and make sure more timing advance doesn't wake the car up some. You can get a cheap timing light for next to nothing. I know you've said you arent an expert, but I promise this is something you can do yourself. Heck you could facetime me or another member and I will walk you through it.

Alternatively I also think simply going to a chassis dyno for a tuning session is a very good idea. For one it will give you some tangible evidence of if it actually is underperforming. And those guys will easily be able to do some of the simple adjustments like timing, and seeing if your throttle is opening all the way.

[petes67bird]

Originally Posted by RocktimusPryme

I really think you could be making a mountain out of a molehill here. These threads tend to get out of hand, and Im not even saying any of it is bad advice, but I just think you should slow down and try a couple of baby steps.

Before you blow half of your fresh engine apart, I think you should just check and make sure more timing advance doesn't wake the car up some. You can get a cheap timing light for next to nothing. I know you've said you arent an expert, but I promise this is something you can do yourself. Heck you could facetime me or another member and I will walk you through it.

Alternatively I also think simply going to a chassis dyno for a tuning session is a very good idea. For one it will give you some tangible evidence of if it actually is underperforming. And those guys will easily be able to do some of the simple adjustments like timing, and seeing if your throttle is opening all the way.

I agree on that. The issue is I attempted to get someplace by me for a dyno tune last year and was turned away because of the quadrajet. They didn't have anyone familiar with them which seems to be a common scenario.

[RocktimusPryme]

Originally Posted by petes67bird

I agree on that. The issue is I attempted to get someplace by me for a dyno tune last year and was turned away because of the quadrajet. They didn't have anyone familiar with them which seems to be a common scenario.

They don't have to be able to tune it for what you need. They can just make sure its getting full throttle and the secondaries open.

If it needed different metering rods and air bleeds, they might make up a few numbers. But the kinda power loss that you feel like you are incurring wouldn't be from traditional carb tubing. It would be something dramatic like the secondaries not being open, or the choke staying closed.

You are looking for a basic troubleshooting session to make sure there arent any glaring concerns.

You could also borrow a holley from someone and bolt it on with an adapter, those adapters are known to kill some power themselves, but if you feel like the carb might be killing you, you could rule it out that way. If the qjet was that bad, even with a less than efficient adapter, the holley would wake it up.

I really think your issue is either distributor timing or cam timing. Hopefully the distributor variety.

[67Fbird]

For yur combo the iron intake is perfectly fine actually better than most alums for ALL ROUND performance in the 350-400 hp area. If you can change a starter and install a dizzy you do not need a shop to do any of the things most folks have stated!
Degreeing a cam ...time consuming PITA but when it MATTERS....well it matters. only need 3 tools total tool cost about $75 and TIME
Checking the balancer for timing mark correctness ....again easy peezy just like changing spark plugs 1 special tool ...$20
For a simple motor there are MANY folks who can walk you thru a BENCH build/check of YOUR Q-jet that will get you running VERY well. Parts choices ar a bit difficult to find NOW (I think) but still available
BTW glad to see the deck height ###'s to kinda confirm the compression ratio (note the 041 cam recommends 10.5:1 + on compression)

The RAIV cam in a 455 is almost SMALL then you are only using the 1.5 rockrs makes it SMALL with a long duration. you should have torque out the wazoo but your your hp will be a little late to the show. Consider the RAIV is .469 lift with 1.5 rockers YET the ACTUAL RAIV used 1.65's which netted ..513 lift...on a 400 cid....you can see this cam is a bit small when you add 60 cubes..BUT still a great runner!

So now I think the big question associated with the ask is

PLEASE DESCRIBE LAZINESS OFF THE LINE?

If you have a 2800 converter and 3.73 gears.....unless you are running 11.5 slicks and a 2 barrel with caltrac's......you should NOT BE getting TRACTION! if you hammer it.

I don't think you need to go nuclear with a set 310 heads single plane intake MSD ignition....%^&*( you just have some parts that are NOT tuned together

[Jay S]

Some time tuning on a wheel dyno sounds like a great idea.

[chiphead]

Originally Posted by RocktimusPryme

I really think you could be making a mountain out of a molehill here. These threads tend to get out of hand, and Im not even saying any of it is bad advice, but I just think you should slow down and try a couple of baby steps.

Before you blow half of your fresh engine apart, I think you should just check and make sure more timing advance doesn't wake the car up some. You can get a cheap timing light for next to nothing. I know you've said you arent an expert, but I promise this is something you can do yourself. Heck you could facetime me or another member and I will walk you through it.

Alternatively I also think simply going to a chassis dyno for a tuning session is a very good idea. For one it will give you some tangible evidence of if it actually is underperforming. And those guys will easily be able to do some of the simple adjustments like timing, and seeing if your throttle is opening all the way.

I agree. This motor should be 385-410 HP at about 5400 RPM easy. It may be lazy down low but should pull really hard up top. It should break the tires loose from a stop. I wouldn't just throw parts at it just yet. Even a new expensive holley is going to need tuning. Most new holleys need a lot of invasive work because of the new fangled metering blocks they use now. Find my thread here on tuning my Quickfuel 750 double pumper. Took a year of screwing with it to get it running really right. AFR wide band and a vacuum gauge mounted inside the car will show the straight facts. I have them on my '67 LeMans under the dash. With those and a tach, I can tell exactly what the motor is doing.

A RPM dual plane intake is a very good intake. I've run them on several 400s with Q-jets and Holleys, even spraying nitrous, they flat work. As long as you have the hood clearance, you can't go wrong with it. Other than that, tune it, as I've said before.

Frankly, if you're going to own a car like this you need to learn how to work on it some. Get a timing light and a vacuum gauge for Christmas LOL.

[chuckies76ta]

Originally Posted by petes67bird

Thanks, I am going to a shop today near me to discuss the cost of getting the cam degreed. Would you do anything to the heads, intake or carb? I have the opportunity to swap my quadrajet which is is 750cfm with a fully rebuilt 800cfm with electric choke. He said he can modify it to my iron intake choke system if needed. I do not know about quadrajets at all, so I am not sure. I was thinking maybe degree the cam, get a RPM manifold and a holley that I can adjust myself.

Like mentioned in one of the post. (#49) Slow down.
Focus on getting the cam degreed and do some turning and setup your timing from there.
Leave your heads and intake alone. You can try the 800 cfm Q-jet see how it works. Electric chokes work fine for what your doing. The only issue I ever had with a Q-jet was keeping the fuel bowl full at higher rpm, but that was in my fuel system delivery.

Down the road you can build yourself another engine with more H/P and performance if that's what you want. There are lots of smart folks on this forum who can help guide you in a future build.

[Bill S]

I just noticed in the first post, "quadrajet by Cliff".

[petes67bird]

Originally Posted by chuckies76ta

Like mentioned in one of the post. (#49) Slow down.
Focus on getting the cam degreed and do some turning and setup your timing from there.
Leave your heads and intake alone. You can try the 800 cfm Q-jet see how it works. Electric chokes work fine for what your doing. The only issue I ever had with a Q-jet was keeping the fuel bowl full at higher rpm, but that was in my fuel system delivery.

Down the road you can build yourself another engine with more H/P and performance if that's what you want. There are lots of smart folks on this forum who can help guide you in a future build.

Thanks. I went to my local shop yesterday and chatted about some things. His train of thought was that my compression may be lower than what I had previously thought (he thinks it may be closer to 9:1 or even upper 8's) which would adversely affect the cam I have that he feels would benefit from a higher compression above 10:1. His suggestion was that we can leave the cam where it is, I can install heads (he wants me to drop to 72cc Eheads that he will go through and change the springs on and get me near 11:1), and cleanup my intake and 750cfm carb (said it looks like my accelerator pump is leaking gas). He said this should raise my compression, add about 50-80 horsepower and he can then time and curve everything for me on his equipment. He personally did not like the #96 heads, he also said that all the Kauffmans he has flow tested have not reached advertised numbers, which is why he is wanting me to go with the Edelbrock. We ended up chatting for several hours while he showed me all of his work, great guy.

[petes67bird]

Originally Posted by Bill S

I just noticed in the first post, "quadrajet by Cliff".

It should be Cliff's rec, im not sure why my phone didnt keep the rec part(reccomendation or however you spell it which is why I abbreviate it, he recommended a great builder) I apologize for not catching that. I cant edit it but if the mods can, that would be great. He told me he wasnt rebuilding and gave me a name/ number. He did the same for my converter and advice on my Transmission. Cliff was a blast to chat with and a stand up guy. This is my first Pontiac, so I have been trying to follow the advice of Pontiac people and do things correctly. I have been fortunate enough to have some great conversations with great people willing to share their years of knowledge with someone who knows far less then them. Also some terrific stories!

[78w72]

Just my .02 but I think you are comparing the basically stock cam engine to your friends stroker & BBC engines that are probably not stock or cam'd so small. You simply arent going to be as fast as those types of engines using a basically stock cam....

If you decide to go to the trouble & expense of degreeing the cam, you are probably much better off just replacing the cam with a better/bigger one that will still be perfectly streetable but will make more power than a factory type grind. Lots of different cams suggested for big 455's or in your case a 462 being bored .030. Cliff & others like the crower 60919? cam in these types of builds.

Also there are places out there & some members on here that can build a Q-jet to your engine/car specs for not much more money than building or buying a new comparable holley. Also if you go electric choke Q-jet, it doesnt need any mod's for your iron intake choke, its electric and works independently of the hot air choke on the intake.

Basically, if you want to degree the current cam, just replace it with a better one that will make more power. Porting the heads will be expensive, probably better to look for a used set already ported or get alum heads if thats in your budget.

Lots of ways to get some more power but I doubt paying to degree the current cam will get you the power increase youre looking for. Hope you can get it sorted out without too much expense.

[John Milner]

Originally Posted by 78w72

Cliff & others like the crower 60919? cam in these types of builds.

That is basically the same cam he has in his engine. Specs on the Melling 26308 are: 231/240 .470 .470 113.

Should be a strong runner. Adding compression should help. I still feel like it should melt the tires at will with the 96 heads. I run a similar cam in a 10:1 428 with a 4 speed and 3:23 rear. I have never taken it to a race track and doubt I will but the first 2 gears are pretty useless if you crack the throttle open from a roll.