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Discussion Starter #21
OK, I pick up on the 400 engine that was all stock parts and ran 12.65 at either 108 or 109, I don't remember for sure. Now I'm tired of the car being a sleeper and I install a large cam. One that should have been way too big for what my 400 would want. I take it to the track and it runs 12.59 at 110. Since my car is no longer stock, it's time for headers. My good Pontiac friend had a spare set so I bought them from him. They were 1 3/4" tubes, truly equal length and clocked. Clocked means the exhaust at the collectors is assembled to follow the firing order. If you looked into the collector from the rear, the exhaust pulses would be going clockwise or counter clockwise. The "normal way they criss-cross, and the reason for that is easier routing of the tubes. This results in a circular motion in the collector which helps scavenge the exhaust. They have one tube over the frame on each side because of the routing required to make them "clocked". The brand is Headers By "Ed". They got so expensive I think he quit selling complete headers, and went to kits.

So I had to cut part of my fender well out by the clutch bell crank for the tube over frame. The tube bolts in separately, after the other three are in place. Although these headers work well, they were optimized for drag racing. The tubes were thin and a couple of bolts were difficult. One is almost impossible. I've spent as much as 6 hours on one of the bolts. It's the fourth bolt back at the back of the #5 and #6 cylinders. The tube wraps right around the bolt. The best way to get them on is to slot the flange, install the difficult bolt, and pull the headers over the bolt. It's still difficult, but threading the bolt with the header in is impossible.

OK, the punch line. The car ran 12.20 at 114. It's clear the RA manifolds became a restriction. Either because the cam was too big, or because they didn't like a 110 degree LSA. I drove the car this way for several years. It did sound pretty nasty. In 1978 I started building a 428. It took me three years, but the 400 was still running great. During those three years I decided I would put a nitrous system on the car. Remember, I'm street racing it, and using it for transportation. I'll pick up here next time.
 

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Discussion Starter #22
Well I don’t think I really have any issues with the tri power... I was just thinking in general with that 750 it probably has more guts... but maybe not it’s hard to compare with the first build. Definitely had more horsepower in the first build and when I put my foot in it it would throw you back in the seat with the Edelbrock 750... never had the tri-power first build.. i’m curious what horsepower this has now and someday I would like to put it on the Dino to have it tuned and horsepower rating..
Run the tri-power.
 

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Discussion Starter #23
So now I'm building a 428, but I want to put nitrous on the 400 that is still in the car. My plan was to grind out the exhaust cross over and plumb the nitrous lines underneath. I wasn't trying to hide it, I just wanted it clean. So I go about hacking and grinding to get the exhaust cross over gone. Easier said than done when you don't have the right tools. But I got it done adequately. I could have cleaned off the ribs on the sides better, but I was kind of fed up. When I'm finished I send the manifold to Marvin Miller. I think they were in Burbank at the time, which is about 100 miles away. I think I'm in good shape until I get a call from them saying they can't plumb it directly into the ports. I ask why. They say "ooooo, it's cast iron". I say yeah, all the factory tri-powers were cast iron, surprise. Why can't you do it? "Ooooo, it's cast iron". Well, if it's hard on your tooling I will replace it. "Ooooo, it's cast iron". No matter what I asked I got the same response. They never did explain it to me. But they did make me a deal on a plate system, which in hind sight I think is better. The only down side is the air cleaner on the front of the carburetor hits the cross member on the hood. So I bent the cross member. The system was advertised as a 125 HP boost. I don't think I have any pictures of the first system, but it comprised 4 solenoids. Two small one for fuel and two small ones for nitrous. I made a mounting plate to go over the heater housing so I could take it off easily. I'll show picture later. They did a nice job with the stainless steel lines. The biggest issue with removing everything is that it now requires 6 gaskets for the carb bases. I also had to mount a nitrous tank somewhere. I chose to put it basically where the spare tire would have been. I had to drop the gas tank to mount the lower rails. I did this by myself and didn't totally empty the gas tank so needless to say I couldn't balance it. It isn't very pretty, but I got it all done.

I go out for a blast and it runs better, but nothing like I thought it should. My guess was that it was closer to a 75 HP boost rather than 125. So I play with this on the street until the 428 is done. I planned on removing the engine on a Sunday, so I took it to the track on Saturday. It ran 11.85 at 119. I could barely get it into 4th gear (M-20) because the pilot bushing was toast. I forgot to mention that the crank that came out of the '68 Firebird was not machined for a pilot bearing. I didn't know it until the engine was finished and I was getting ready to install the clutch. I didn't want to take it all apart so I had a tool made to turn down some bushings that would go into the unfinished hole of the crank. I've attached a picture. When I pulled the 400 out it was clear that the input shaft was wandering all over the place. The hole in the bushing was pretty big. From that time on one, of the first things I do is check the crank to assure the 7109 pilot bearing will fit.

I did do two other things for the nitrous implementation. I was afraid the Holly blue regulator would not flow enough fuel, so I added a second one. I drilled holes in the alternator bracket and put both of them there. One was for the carbs, and the other for the nitrous solenoids. I was also afraid the fuel pump couldn't keep up, so I took off the mechanical pump and added to electrics. Down the road I put the mechanical pump back on and kept one electric as a pusher. During my "shake down runs" I put an oil pressure sending unit into the fuel line and sent the signal to the light on the dash. It turns out that sending unit activates at about 4 psi. Driving home from work with 1 pump the light had a slight glow. Hit the gas and it would go solid red. With two pumps the light stayed off. OOPS, another thing I forgot. How to activate the nitrous? I didn't want a manual switch to mess with while I was shifting gears, so I made a bracket to mount on the right rear stud of the rear carb. The carbs have to be wide open before the nitrous engages. I do not have any other controls on it, like oil pressure or water temperature.



Jim4.JPG Jim5.JPG Jim6.JPG Jim9.JPG GTO N2O Trunk.jpg IMG_20171123_094144.jpg IMG_20171208_105428.jpg Pilot Bearing.jpg
 

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Discussion Starter #24
I forgot to mention one thing. Since I had ground out the entire exhaust cross over, the center intake manifold bolts were unsupported on one side. So I made block off plates. They didn't really need to block the exhaust as the heads were welded up. But I needed to have the bolts supported as well as the factory did. You can see them in the picture. This is before I trimmed the manifold gasket.

DSCN4529 small.jpg
 

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I’m loving this story!

I’ll have to chime in with mine, after I put together a few notes. My memory sucks!

here is just a teaser...

bought my first car, a ‘69 GTO RAIII, 4 speed at the age of 18 in ‘90 off my brother, so he can buy his first house. I knew nothing of Pontiac power, as all my friends had Chevys....
135186
 

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Discussion Starter #30 (Edited)
Well, I'm back. Life got in the way, and I had to rack my brain to see if I rebuilt the 428 between 1981 and 2000. I guess I didn't. One problem I did have when I first got the new engine running was the breaking of rocker studs. Every few miles it would snap one right off. I got to where I carried spares. It turns out mine weren't strong enough for the cam I was running. It was a hydraulic flat tappet with 260/260 degrees at 0.050" lift on a 110 LSA. Net lift was about 0.600 with 1.65 Crower stainless steel rockers. B/T/W, I'm typically against running a single pattern cam on a Pontiac, but I was hoping it would actually kill a little bottom end. I was still having a bit of fun on the street, and I didn't want the tires to spin too easily (from a roll). I upgraded to 4340 steel rocker studs. They same ones are still in the engine. The only upgrade I did to the engine since 1981 was to add a larger nitrous system. All I changed were the solenoids. My updated nitrous solenoid will flow more than my bottle, although the bottle is an old gas bottle. I got it before they started making nitrous specific bottles. Anyway, the power assist is now limited by the hole sizes in the tubes that are in the plates. The best estimate of horsepower boost by the company NOS was about 150 horsepower. Now there is enough flow to keep the nitrous in liquid form up to the nozzles, then it turns to gas when it exits. This provides better distribution and more cooling of the charge. In 1989 I updated the drive line. I changed the transmission to an M-22 Rock Crusher, and I put in a new Moroso posi and new 4.33 gears. I figured if I was ever going to the track, now was the time. So I go to Carlsbad the Saturday night before Easter. It turned out they were prepping the track that day and night to prepare for a big event on Easter day. I didn't know that until I tried a few runs without nitrous. I was running 29.5" x 9" Firestone slicks. It bogged BADLY. The runs were in the low to mid 12's. I was trying to characterize the setup to my old ones, but then I figured I was just wasting runs. I'm an engineer by profession, so I always try to think things through. From my past experiences, I was expecting this combination to run about 11.25 at about 125 mph. I turned on the juice, raised my launch RPM from 3000 to 5000 and let 'er rip. The first run was 11.05 at 122. I couldn't figure out why it was quicker in ET but slower in mph than I expected. So I'm driving back up to the starting line to make another pass. All of a sudden it's like something in the engine broke. So they push me over by the ambulance, and I start working on it. I wanted to get it to TDC first, so I pulled the plugs to make it easier to turn the engine over. I got the plugs out and three of them did not have any electrodes. I'm trying to think it through, saying I know nitrous doesn't like to run lean, but I've got two fuel pumps. I looked under the dashboard and saw that I had never turned on the electric pusher pump. I didn't usually need it on the street because we didn't typically go that fast. OK, I turn on the electric pump and do another bonsai launch. It felt really good until I got to about 900-1000 feet. I was used to the back end moving around due to slick walk. When I got over about 122 the front end starting moving around. I don't have the lift limited on the front end, so it goes up pretty high. I will try to attach a short clip of it running with street tires so you can see. Now I've got both ends sashaying around, and the sensation was that the sides of the track were starting to go to a vanishing point. It scared the hell out of me, but I'm thinking I want to keep my foot in it all the way to the end, because I don't ever want to do it again. Not only did I make it passed the finish line, I was even able to stop before hitting the hill at the end of the track. I've still got drum brakes all the way around. The result? 10.80 at 129.31! OK, I'm done. It was too scary, and it was fast enough to require a roll bar. That will never happen in this car. OK, I get it home safely and take it to work on Monday. I'm in the parking lot at the plant, slow down to go over a speed bump, let the clutch out - and the car just squats. I had broken first gear and the cluster in a rock crusher. That was the last time the car would ever have slicks on it again.

So I put in a new M-22 and just enjoyed it. Typically I would take my oldest granddaughter out for breakfast or donuts on a Sunday. We were leaving in the year 2000 and I couldn't get the engine to turn over. The starter had eaten up part of the flywheel. I managed to get it going and keep it running until I got home. The flywheel is hard enough to get to, and the engine had been in for 19 glorious years, so I figured I'd take the whole thing out and freshen up the engine. The real odyssey starts after that.

PS - I hunted for the clip with street tires, but apparently I never put it on YouTube. If you can bear with the bad films, it starts at the 4:20 mark of the attached link.

. tn_PAL_9399cs_16.jpg GTO N2O Trunk.jpg tumblr_mpq8lxJEqW1sxljhto1_500-00.jpg

 

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Someone should make a movie from all this history. Love it and what a great read. Thanks for sharing Jim your a legend in the Pontiac community. Cheers sir!
 

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Discussion Starter #33
Love the story,and the video that race talking about putting a car on the trailer
Although that car I raced was a full size Chevy, it had a hopped up 454. I hate getting beat off of the line, but I had street tires. I had to slowly roll into the gas, let the clutch out moderately, and have the clutch fully engaged at about 1500-1800 RPM. I had never done that before, and I was afraid it would still fry the tires when I finally had it floored. I have to hand it to the M&H street DOT tires, they work pretty well.
 

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Great story Jim. Thoroughly enjoyed the reading. Makes me wonder what my GTO could do on the track. Someday I’d love to have a dynode and then run it down the strip for at least one run. LOL
 
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