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#41
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This is my brother's numbers matching original 56,000 mile '69 350HO/M20/3.55 rear Firebird with mostly original paint at the 2019 TA Nat's. It came with the Décor option and has it's original full size wheel covers (not on in this picture). The original engine (w/ 48 heads) was rebuilt by the previous owner and is very strong. It has an actual 9.5 compression and 067-ish cam in it (204/214/112) very similar to the Summit 2800. The butt-o-meter says mid-13's and it drives so nice...gets 18-19 mpg too!
Dennis |
#42
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Really nice looking example; thanks for posting. I’d be dubious on the performance AND mileage claims as both being accurate together on the same car. What is the car’s typical range on the highway on a tank of fuel? I would expect ~200 miles or so with that combination.
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'69 R/A III Firebird Convertible 14.0s @ 100.8mph AMA/OEM/OER |
#43
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From the performance perspective, the previous owner to Dan brought the just-purchased all original (50k miles) Firebird up to the Pure Stock Drags (2011) and managed to a run 14.38 at 98.66 mph with the original 3.55 open rear end on new repop Firestone F70-14’s on 14x7 Rally II’s…pretty good I’d say. Before the next race (2012) he had rebuilt the engine (stock bottom end with .030 forged pistons) with a pretty big CC cam (XE268: 224/230/110 @ .477”/.480”)…way too big for the 350. It pushed to power band higher than it was designed to rev with no low end torque. The compression wasn’t maxed out and Whistled at 9.5 to 1 warm. The pistons may have a small dish, but haven’t verified. An Eaton posi unit was added and a better 2.5” exhaust system (Flowmaster) was added. With all the changes it ran 13.97 at 100.25 mph (3658 lbs. w/driver) with the poorly chosen cam. Tom Miller ran a 13.63 @ 102.58 in his ’69 Carousel Red 350HO Firebird with a TH400 and 3.73 gears (3576 lbs) back in 2006 (don’t know the engine specs). When Dan bought the car a couple years later, he hated driving it with the CC cam that was in it from the rebuild. Dan worked on the DeskTop Dyno and designed a custom cam that is in between the 067 & 068 cam specs with .425” lift. He designed it for maximum torque yet good hp, like Mac McKeller did. It’s in the 206/218/113 range. The smaller cam made a huge difference with how the car drives and makes its power in the low and mid-range now and revs to 5500 rpm easily. Tom Miller drove the car this summer and said it felt faster than his old ‘69 350HO Bird. It has to be proven on the track someday, but Dan and Tom have enough seat time to make fairly accurate predictions. This is not meant to be an argument, but clarifications. I can honestly say we have all been impressed with the performance potential of the Pontiac 350HO’s and shouldn’t be overlooked. They run just as well with the small valve heads. Sorry about the long read. Dennis |
#44
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Hey Dennis, hope you’re keeping well. Thanks for the reply and no need to apologize for the detail. As you probably know I’ve made the drive from Toronto to the PSD and then raced ‘Iron Man’ as well. My honest blueprinted combination averages about 200 miles to a tank of fuel (Dan has my car spec’s). That equates to about 11 mpg cruising around 60 - 65 mph. I’m not arguing with your claims (the 350HO is a cool package) it just seems incongruent with my own driving experience. Maybe it’s the Canadian gas!? lol
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'69 R/A III Firebird Convertible 14.0s @ 100.8mph AMA/OEM/OER |
#45
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Did Mr. Miller later drive a '69 Buick with a 350? If so, he had pretty good times with it also.
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1971 Pontiac Trans Am Cameo White 1968 Firebird 400 coupe, Verdoro Green w/black vinyl top 1968 Firebird 400 convertible, Verdoro Green w/black top 1970 Buick Skylark Custom convertible(driver) Fire Red 1972 Buick GS 455 Stage 1 Royal Blue |
#46
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Giant Killer.
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#47
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Stay Safe! Dennis |
#48
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Dennis |
#49
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Dennis |
The Following User Says Thank You to SD455DJ For This Useful Post: | ||
#50
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That would be the one!
Apparently, laid waste on a few big blocks, too....like this 440 Roadrunner! https://www.youtube.com/watch?v=O-pT4E-WziM ...love it when the "underdog" takes it to a pentastar product.
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#51
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I need to make a few corrections...the milder cam that Dan installed is actually 203/216/112 @ .422"/.438" lift, so a little milder. The cam that he removed is a Crane H-278-2 (222/234/114 @ .467"/.494" lift), which is a good cam for a 10.0 400 with big valve heads and RA manifolds. The replacement exhaust system is a Pypes crossflow w/X pipe system with the 2.5" headpipes.
The 48 heads combustion chambers measured in at 66.7 cc's average. He didn't find any marks or stampings to distinguish this head from the bigger chamber 48's used on 400's. The pistons are .030" in the hole (!) and uses .040" Cometic head gaskets (.070" quench!!...not ideal). The block is still standard bore (3.876") and has Silvolite cast pistons, not forged as I thought. Dan would have done many things different on this numbers matching 350 if he rebuilt it, but it does run good. The static compression calculates out to 9.45. If it was zero decked, it would be close to 10.0 to 1. Dennis |
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#52
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Dennis, did you ever race at St. Louis in the late 80's possibly early 90's in a 'Stock' type race? (can't remember what they called it)
I raced there and there were not many Pontiacs. Got down to 10 cars (they paid to 8 ) A friend went there with a 71 TA, can't remember how he did, went a few rounds.
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#53
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Camshaft make and model please? Ponchy
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#54
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Dennis |
#55
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Dennis |
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#56
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I am surprised no one mentioned this sooner:
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all four castings were used in engines that had the same (or similar) horsepower ratings. I believe that of late, there have been some corrections in this matter, so I am typing this in hopes of helping to set things straight: 1969 #62 heads = 77cc (aprox) 1970 #13 heads = 77cc (aprox) 1969 #48 heads = 67cc (aprox) 1970 #12 heads = 67cc (aprox) 1969 'L78' 400-4bbl 350hp WX/XH/YS/YT = #62 heads 1969 'L78' 400-4bbl 350hp WT = #48 heads 1970 'L78' 400-4bbl 350hp WX/XH/YS = #13 heads 1970 'L78' 400-4bbl 350hp WT = #12 heads All L78 engines for these years used 'regular' 750cfm carbs with pull over enrichment airhorns, standard cast iron four barrel intake manifolds, and standard "log" exhaust manifolds. For both years, these engines when installed in Firebirds carried a 330hp rating. All these engines used 067, with just two exceptions: 1) XH engines installed in full sized cars with automatics used a 066 cam. 2) early(?) 1969 WT engines used a 068 cam. For both of these years, the Tempest/Lemans/Firebird when equipped with this engine and a manual transmission, were the 'hot ticket' because they used the higher compression "Ram Air III" heads. I used to go along with the assertion that supposedly some automatic RAIII engines were purported to have 62/13 heads, but I am incline these days to believe that was bunk. Quote:
Even the 75-77 L76 350-4bbl engines seem overlooked, when they are better than I'd wager many people think they are. I just looked for the picture that I could swear I remember taking, but couldn't find it; I believe it was at the 2018 Portland Swap meet, that someone (in the far east building) was selling a whole (taken apart, less carb) 1968 Pontiac 350HO; Since I like these, it piqued my interest, especially since no one seems to pay them any attention or ever offer them for sale.
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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#57
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Thank you very much for that info. Ponchy
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#58
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The first car I bought at age 16 was a 1967 Firebird 326 HO HD 3 speed on the floor with standard 3.36 open axle.
Loved that car, in stock form it was a real ripper.
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Rich Johns Owner/Operator of Pure Stock Auto Restorations Inc. www.purestockauto.com 1969 GTO Judge Ram Air IV M21 4 speed 3:90 1970 GTO Judge Ram Air III M21 4 speed 3:90 Oshawa Built 1970 GSX Stage 1 M21 4 Speed 3.64 # 67 of 678 Original Paint 1970 GSX Stage 1 Auto 3.64 # 603 of 678 12.44@109.73 mph 2011 Buick GS Nats Pure Stock, 12.71@110.64 mph PSMCDR 2011 1970 GS Stage 1 Convertible Auto 3:64 12.71@109.15 mph PSMCDR 2009 1970 GS 455 M21 4 Speed 3.42 1987 GN Astro Roof |
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#59
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Don't think I remember that car, I remember there was an AMC (AMX maybe?) that went a lot of rounds. (about the only one there I think)
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#60
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