[GTOKIDRH]

Originally Posted by Sirrotica

One other question, how many miles on the original engine? That originally came with a nylon timing gear in it, and if it is still in there the cam timing may be way off of spec. Retarding cam timing kills low end, so it may be sluggish because of worn timing components. Or you may have cam lobes going away, one or two nearly flat cam lobes pretty much kill power.



For sake of comparison I had a 68, 400 4 bbl Bonneville with the same gearing, got over 17 MPG on a trip, and would burn the single wheel as long as you wanted to hold your foot into it. Stock cam, and single exhaust.



I wouldn't go with 670 heads with the closed chambers, they have a tendency to detonate when running pump gas. If it were me I'd say with the lower compression heads with small valves. You're never going to be in the RPM range to make good use of larger valves anyway. The 389s used the small valves in them for many years in GTOs and most 4bbl engines previous to 1967. Unless you're building this car to be a street racer no need to build the engine like a drag engine is built, on the street you won't have much occasion to get in the 5000 RPM range very much.



Freeing up the exhaust, optimizing the timing curve, richening the jets up a few sizes, and mostly factory parts should get you some stump pulling torque to pull that heavy barge around.



I used a 1973 400 2 bbl engine with a 067 camshaft, and swapped to a Q jet and factory intake to pull around a 5800 lb Jeep truck. Low compression and small valve heads had more than enough power. Before I put the 400 in, I had a 350 Pontiac engine in it but broke a piston, and ended up swapping to the 400, because I had it already to go. Optimizing what you already have should be plenty to move that wagon around at a satisfactory pace.



I almost forgot, I had 2 of the 71-76 clamshell tailgate wagons with 455s in them, low compression, and I wasn't ashamed of how either of those wagons ran. I just optimized the stock parts on both of them, they are much heavier than a 67 wagon is by about 800 lbs, they weighed 5300 lbs.



Pontiac engineers excelled at making low RPM torque to pull their rather heavy cars around, and still keep the RPM down to get at least decent fuel mileage. Wagons have a higher percentage of rear wheel weight by the body construction, so if it won't spin the rear wheels, that's because you have more weight over them than a coupe has, figure accordingly.

Currently it has 108K on the clock. I have quite a bit of documentation that came with the car. I'll look into the timing gear. Never crossed my mind. The cam lobe thought too. That's good info!

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[Scott Roberts]

Didn't read through it all but an 066 cam would t take a 4 barrel... it's punchy with half throttle but if u dump it it will drown.. personal experience..
At 18 I pulled a 68 2 Catalina motor dropped it in a firebird and added a 4 barrel intake and carb... total fail..

[mrmark1957]

I had a '67 wagon as my first car back in 1974 and did the same as you are doing. Q-jet, 4 barrel stock intake and dual exhaust. New timing gears and chain. Shift kit in the trans and spring kit in the distributor. Ran better but the 2.56 rear gear really held it back. It would go to 60 mph in 1st and 100 in 2nd gear. Stop watch 0-60 in 9 seconds. I was looking to swap the rear axle assembly to one with a 2.93 or 3.08 gear setup, but I was rear-ended at a traffic light and the car was totaled.

[25stevem]

Scott, I think that it was your lack of experience / knowledge at age 18 that made your 2bbl to 4 bbl adventure a flop, especially if it was Q-Jet swap over you did!

If nothing else assuming having in the ball park jetting conditions and having full throttle available the car should have had better drivability at low speed and at least 10 to 12 more hp.
I know that would have been the case for me!

[Cliff R]

Here are some dyno runs on a couple different intakes.....

https://m.youtube.com/watch?v=9AfeMtpi5pc

In one of the videos he tested a Pontiac 2bbl intake as well......

[amcmike]

Start with the gears, it'll make a huge impact.

[track73]

I used to own a 67 Catalina 2 door Sport Coupe with a 325 HP 400. It had a Carter AFB and dual exhausts with a 2.41 rear. The turbo 400 trans would shift out of 2nd gear at 90 mph. I learned 35 years after I sold it that Pontiac only made 1300 of that model.

[TCSGTO]

Originally Posted by Cliff R

Here are some dyno runs on a couple different intakes.....

https://m.youtube.com/watch?v=9AfeMtpi5pc

In one of the videos he tested a Pontiac 2bbl intake as well......

I bet at least some of the gain from the 2 bbl to 4 swap was the manifold. The 2 barrel manifold looks like the same runner design as the pre-67 4 barrel intake. The 67+ intake is superior at all Rpm’s.
The 2GC was pulling 7” vacuum at WOT!! That’s enough to start kicking in the vacuum advance.

If you already have the set up I see no reason not to throw the Q-jet and intake on. It’ll only cost $25 in gaskets and a few hours of your time. You’ll get more power AND better MPG’s when cruising.

[25stevem]

Those Holder videos are informative, and I like them, but man why do so many of these guys doing these videos have to so over animated!

Gez, it’s like he drank a 6 pack of Red Bull 20 minutes before the video shoot!

I mean I like that he talks fast enough to get a lot of detail into the video, but to use a automotive term please throttle it back a little will ya!?

[25stevem]

Track73, not only low numbers with the the AFB carb for that year, but those 400s still used the 389/421 type heads also!

[TCSGTO]

[QUOTE=25stevem;6359304]

Gez, it’s like he drank a 6 pack of Red Bull 20 minutes before the video shoot!

People that know him say that’s just his natural personality. Certainly is enthusiastic about his work.

[GTOKIDRH]

[QUOTE=TCSGTO;6359370]

Originally Posted by 25stevem

Gez, it’s like he drank a 6 pack of Red Bull 20 minutes before the video shoot!



People that know him say that’s just his natural personality. Certainly is enthusiastic about his work.

I watched the 2 videos on the Pontiac 400. Very interesting as well as entertaining lol.

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[GTOKIDRH]

Originally Posted by GTOKIDRH

Currently it has 108K on the clock. I have quite a bit of documentation that came with the car. I'll look into the timing gear. Never crossed my mind. The cam lobe thought too. That's good info!

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I run pump gas in my '67 GTO with 670 heads and a slightly dished piston (9.5 :1 c.r.) with no issues. I assume that the full point increase in c. r. will add a little more power to the combination?

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[Formulabruce]

Originally Posted by GTOKIDRH

I have a '67 Full size Safari with the base 400 2BBL auto and a 2.41 posi rear end. I have a 4BBL intake and Quadrajet that I want to install. Eventually I will do a cam swap and exhaust upgrade. I also have a 3.42 posi rear end to swap in. My question is what can I expect to gain if I start with the intake and carb first? Will it be too much for the factory U code cam? Just to be clear my goal isn't to make a hot rod out of it. I just want to wake it up a bit.

I agree with B- man, but I will add. Have you looked at what you have? A L-65 or better? That is around 400 Torque at 2400 RPM, THAT was built to get your beast rolling!! Some of the 2bbl 400' s have 428 Torque and 10:1 cr !! You have the ultimate cruiser set up now. Everything you do now will cost more money to drive it..

[Sirrotica]

Originally Posted by GTOKIDRH

I run pump gas in my '67 GTO with 670 heads and a slightly dished piston (9.5 :1 c.r.) with no issues. I assume that the full point increase in c. r. will add a little more power to the combination?

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Rough figure is 3% of power increase, per 1 point of compression, there are better ways to get that 3% IMO. For sake of discussion, 400 CU IN at 300 HP, raise it i full point of compression and gain 9 HP. You may not be able to run pump gas at that 1 point of compression increase, so then you'll be either changing cams to bleed off low RPM compression, or blending race gas.

I could gain 9 HP with a sharp tune up, bringing the timing in sooner than stock, and richening up the carb and still run pump gas.

I would guess that there is something fundamentally wrong with the OPs engine for it to be such a slug, I worked in a Pontiac dealership in 1970, those cars weren't as slow as he's describing his to be.

I have seen some Pontiacs that someone changed the timing gears, and chain, that were 1 tooth retarded, and run like he's describing. They'll run smooth, but have no low end power whatsoever. Reset the timing gears, and it runs like a different car.

Cutting dishes in pistons is pretty expensive when you can go with a larger CC combustion chamber, and run the stock short block with flat top pistons, but I tend to be practical, and try to save money, especially when it's my money.

I've used Pontiacs from 326 to 455 in daily drivers, used them in Jeep Wagoneers and Jeep tow trucks, plus raced them on oval tracks for years, they aren't slow unless there is something wrong with the internal engine components, or the tune up is way way off. Almost all of my vehicles that were driven on the road would run on pump gas, and were under 9.5 compression ratio. A few of my GTOs were factory rated at 10.5 to 1, and the race car was 12 to 1. I got a lot of work done with relatively low compression Pontiac engines over the last 50 years. All had iron heads.

[Tom Vaught]

[QUOTE=TCSGTO;6359370]

Originally Posted by 25stevem

Gez, it’s like he drank a 6 pack of Red Bull 20 minutes before the video shoot!

People that know him say that’s just his natural personality. Certainly is enthusiastic about his work.

I spent a week at the Bonneville Salt Flats with him and his wife (girlfriend then) in 2001 and he has always been that way. Get used to it.

A very smart guy with boost.

Tom V.

[GTOKIDRH]

Originally Posted by Sirrotica

Rough figure is 3% of power increase, per 1 point of compression, there are better ways to get that 3% IMO. For sake of discussion, 400 CU IN at 300 HP, raise it i full point of compression and gain 9 HP. You may not be able to run pump gas at that 1 point of compression increase, so then you'll be either changing cams to bleed off low RPM compression, or blending race gas.

I could gain 9 HP with a sharp tune up, bringing the timing in sooner than stock, and richening up the carb and still run pump gas.

I would guess that there is something fundamentally wrong with the OPs engine for it to be such a slug, I worked in a Pontiac dealership in 1970, those cars weren't as slow as he's describing his to be.

I have seen some Pontiacs that someone changed the timing gears, and chain, that were 1 tooth retarded, and run like he's describing. They'll run smooth, but have no low end power whatsoever. Reset the timing gears, and it runs like a different car.

Cutting dishes in pistons is pretty expensive when you can go with a larger CC combustion chamber, and run the stock short block with flat top pistons, but I tend to be practical, and try to save money, especially when it's my money.

I've used Pontiacs from 326 to 455 in daily drivers, used them in Jeep Wagoneers and Jeep tow trucks, plus raced them on oval tracks for years, they aren't slow unless there is something wrong with the internal engine components, or the tune up is way way off. Almost all of my vehicles that were driven on the road would run on pump gas, and were under 9.5 compression ratio. A few of my GTOs were factory rated at 10.5 to 1, and the race car was 12 to 1. I got a lot of work done with relatively low compression Pontiac engines over the last 50 years. All had iron heads.

Thanks for the intel! Again, the stock engine in my wagon has the low compression 8.6:1 pistons as well as the large chambered heads. My thought is I already own the 670 small chambered heads which will only push me into rhe mid 9s compression wise which is still pump gas friendly and I will gain 3% more power than why not? It's free. I won't change the heads until I do the cam swap. I'll be in there anyway. I admit that i know just enough about engines to get myself in to trouble. Still much to learn. Thoughts?

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[Dragncar]

I grew up with a 66 Catalina station wagon. 3 on the tree, manual brakes. It had a 10-1 389 in it and my dad went to the junkyard and put a AFB intake and carb on the old girl that got us from CA to Oklahoma twice.
It ran great, got 20 mpg on trips.
Still have the intake and carb. I have 2 AFB intakes, one is flat and one is more of a high rise.

[Formulabruce]

Originally Posted by GTOKIDRH

Thanks for the intel! Again, the stock engine in my wagon has the low compression 8.6:1 pistons as well as the large chambered heads. My thought is I already own the 670 small chambered heads which will only push me into rhe mid 9s compression wise which is still pump gas friendly and I will gain 3% more power than why not? It's free. I won't change the heads until I do the cam swap. I'll be in there anyway. I admit that i know just enough about engines to get myself in to trouble. Still much to learn. Thoughts?

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That 3% Increase in power is NOT going to be in your normal driving RPM range, IF it was, Pontiac would have done it..... ALL, and I mean ALL, Horsepower increases are at higher RPMS, and Most all are Not used in normal driving.
ALL Horsepower is calculated, even at the dyno, its Never measured.
You have a nice car, hate to see it get into "mission creep" and not enjoyed..

[amcmike]

Originally Posted by Formulabruce

That 3% Increase in power is NOT going to be in your normal driving RPM range, IF it was, Pontiac would have done it..... ALL, and I mean ALL, Horsepower increases are at higher RPMS, and Most all are Not used in normal driving.

Actually it is, and today's OEMs do.

Modern engines use much higher compression ratios, enabled by direct injection. The higher SCR increases efficiency even at part throttle, thus increasing fuel economy (in addition to increasing torque under wide open throttle). They can get away with these compression ratios due to the charge cooling as the fuel is injected directly into the combustion chamber (especially with multiple injection strategy at under medium loads and low-mid rpm). This then allows them to downsize the engine displacement (if desired) to further improve fuel economy. This is why OEMs use DI even on small economy cars, not just performance vehicles.