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#21
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The OP might want to try and find a build article in HPP mag where Jim Taylor put together a 421 with ported iron 389/ 421 heads that made 478 hp, and as I recall it put out 350 HP just running on the center 2 bbl carb only!
My hats off to that man for accomplishing that and sharing the details also!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#22
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https://www.hotrod.com/articles/h-o-...-build-part-1/
https://www.hotrod.com/articles/h-o-...-build-part-2/ |
#23
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i built a 467with ported eheads aluminum tripower intake we welded top of intake do ports would line up and seal a gasket
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2008KRE Q16 Winner 2014 atco raceway doorslammer winner 86 grand am tube car 8.95 @152 455 eheads solid flat tappet cam Hoffman Racing building and racing Pontiacs for 35 years |
#24
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Hey Kenth, if you happen to read the second part of this Hot Rod article above in post 22, note the jetting changes that Jim had to make to that tripower carb set up!
Gee! I guess he just does not know enough to keep it stock does he?
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#25
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Im not sure what the difference are but we sure have never been able to run those little jets in our tri-powers in the end carbs.
Jet to what the engine wants. |
#26
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Quote:
I just realized how little I know. So as the engine heats up the intake tract dynamics change? SO, should you flow test an intake head combo with the metal heated to temp? |
#27
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What tri-power carbs would support 600 + hp?
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#28
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Keep in mind that the later heads have larger valves and the valve angles are different than the #77 heads. You may have issues with valve clearance -to- cylinder wall and pistons depending on lift. Valve notches may have to also be added to the tops of the cylinders to unshroud the valves. If rebuilding the engine, then replacement/matching parts will take care of the mismatches. Still may want to notch the tops of the cylinders. Install the cast iron RA exhaust manifolds to save some frustration, but headers will work. I would also want a minimum of a 2 1/2 dia exhaust (prefer 3" dia myself) and high flowing mufflers so as not to choke the engine. |
#29
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That is a great article from omt. I forgot about it. Super cool putting a value on the outer carbs in hp.
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#30
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Hmm. Well I was not planning to open the bottom end. As it stands it has pretty deep dish forged pistons already, having no info on the build from po, I’d guess it’s at least .30 over on a 421. Enough side to side space for 2.11/1.66 valves?
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#31
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If it where me, save the original heads and intake.
Use out of the box E-heads and aluminum intake. Enlarge intake runners all way up. 1/2" 2 hole spacers on all 3 carbs. SFT cam around 240/250. Easy 11's with 3.42-3.55 gears.
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If you cant drive from gas pump to gas pump across the map, its not a street car. http://s207.photobucket.com/albums/b...hop/?start=100 |
#32
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Intake air flow in a NA motor goes down the runners in pluses in a on and off fashion.
These pulses will curtail the flow of air once the speed of these pulses reach 55 to 60% of the speed of sound. This is because it takes energy to restart the air mass once it has stopped. The speed of sound is stated as being at standard temperature and pressure at sea level. This all means that as the intake air mass heats up on its way thru the complete intake tract that maximum velocity that it can attain before the cut off point is reached is taking place at a lower rpm. Now this does not mean that super cold air will make the most power as the air temp and the fuels make up must be enough to turn the fuel into a nice burning vapor along with some fuel mist that will later be turned into a vapor when it’s cramped up at TDC. Also interestingly enough if your thinking that having all the fuel turn into a vapor would be the way to go you would be wrong! Excess Fuel vapor takes up room that could air at a certain point and this then makes for a reduction in power output just like having not enough fuel going into a good burnable vapor !
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#33
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^Way to complicated for me^
Not sure if way I built my engines over the years, but the hotter they get(200-210 degrees), the faster they run.
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If you cant drive from gas pump to gas pump across the map, its not a street car. http://s207.photobucket.com/albums/b...hop/?start=100 |
#34
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Quote:
Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#35
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Cooler air is more dense meaning there is more of it. Probably why the cold air intakes are so beneficial.
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#36
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4,000 thrust HP and 4,785 ft pounds of torque - honest. You just gotta know all the scientific stuff because it matters, right? I can't believe anyone would just slap a 500HP engine together without knowing all the related scientific formulas and what is needed to make it all work and then take it to the track and run 11's only to have some other Pontiac guy want to know what your sound wave pulses ratio is between intake plenum and exhaust heat flange. How embarrassing in not being able to answer such a basic question - then everyone will know you are a rookie in the engine building skills. |
The Following 2 Users Say Thank You to PontiacJim1959 For This Useful Post: | ||
#37
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Don't forget AlTITUDE - dense air versus thin air, and of course don't forget about humidity. All basic knowledge found in the 1969 Chilton's handbook of the best 6-second Pontiac engine builds for street racers, and dummies. Book comes with a slide rule to generate all formula answers.
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The Following User Says Thank You to PontiacJim1959 For This Useful Post: | ||
#38
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^I'm still a rookie^
Nichols Engineering did machine work on ours. I was running low 11's at age 20 back in 79. Course my father and brother had a lot to do with it. 68 FB 400ci 256/263 SFT iron intake w/a Q-JET. TH400 3.55 gears. Got 16 mpg around street. I've helped assemble 500 to 1000hp NA plus engines at my buddies shop since 85. A lot of power adder engines too. Learned a few things along the way...
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If you cant drive from gas pump to gas pump across the map, its not a street car. http://s207.photobucket.com/albums/b...hop/?start=100 Last edited by Region Warrior; 03-06-2021 at 01:23 PM. |
#39
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#40
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